JP2000138419A - Semiconductor laser element and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize a waveguide structure and a current constricting structure together by constituting at least the layered part of a semiconductor laminate having a light guiding function of a compound semiconductor layer containing phosphorus. SOLUTION: A ZnO film 111 is deposited on a semiconductor substrate by the sputtering method. Then zinc is diffused from the film 111 by heating a wafer on which the semiconductor laminate is formed to a temperature between 500 deg.C and 600 deg.C in a nitrogen atmosphere. Of the zinc-diffused area, a compound semiconductor area 105 containing phosphorus as a main group V element can secure a high resistance value together with the refractive index change of the material, because the resistance value of the zinc-diffused area 112 of the second clad layer 105 composed of n-type (Al0.7Ga0.3)0.5In0.5P containing phosphorus as a main group V element increases. Namely, the zinc-diffused area 112 constitutes a waveguide and, at the same time, a current constricting layer. Therefore, no additional current constricting structure is required.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a highly reliable semiconductor optical device, particularly a semiconductor laser device and a method for manufacturing the same.

[0002]

2. Description of the Related Art AlG which is a typical example of a compound semiconductor
In a quantum well structure semiconductor laser device using an aAs system, attempts have been made to realize a refractive index waveguide structure without providing a step or the like in a semiconductor crystal. A transparent region is provided in which the target quantum well structure is mixed and crystallized while maintaining a flat crystal face. The alloying of the quantum well structure is performed by performing zinc diffusion (Zn diffusion) in a desired region outside the laser waveguide.

[0003] As a conventional technique, for example, H. Nak
ajima, Jpn. J. Appn. Phys.
24, L647P (1985). According to this document, in an AlGaAs-based semiconductor laser having a quantum well structure, a transparent region in which a zinc well is mixed to crystallize the quantum well structure and a refractive index with respect to laser light is changed is provided in a region outside the laser waveguide. FIG. 1 shows a cross-sectional view of the configuration of the document. In the figure, 1 is a p-type GaAs substrate and 2 is a p-type GaAs substrate.
Cladding layer made of p-type AlGaAs, 3 is p-type AlGa
4 is a light guide layer of As, 4 is a region of a multiple quantum well structure, 5 is a silicon dioxide layer for passivation, 6 is a light guide layer of n-type AlGaAs, and 7 is n-type AlGaAs.
Reference numeral 8 denotes a cap layer made of n-type GaAs, 9 denotes an n-side electrode made of Au-Ge-Ni / Au, and 10 denotes a p-side electrode made of Cr / Au. An impurity region 11 for zinc diffusion is formed in these semiconductor laminates. The region of the quantum well structure in the impurity region is a mixed crystal region.

[0004] When the quantum well structure is mixed, the bandgap of the active layer is increased. Therefore, the quantum well structure becomes transparent to the emission wavelength of the original quantum well structure that is not mixed and has a small refractive index. This makes it possible to realize a refractive index waveguide structure without providing a step or the like in the semiconductor crystal.

[0005] Disordering of constituent elements of adjacent compound semiconductor layers by zinc diffusion has been performed for a long time. For example, it is found in Japanese Patent Publication No. 51557/1988.

[0006]

In the above prior art, the impurity diffusion for changing the refractive index and forming the transparent structure greatly increases the impurity concentration of the semiconductor layer. The introduction of such a high concentration of impurities has caused unnecessary light loss in the waveguide. Further, there is a problem that a leakage current is generated outside the waveguide.

[0007]

SUMMARY OF THE INVENTION The present invention relates to a compound semiconductor material containing phosphorus as an element of the group V element or a compound semiconductor material containing nitrogen as an element of the group V element. It is based on the finding that the introduction of impurities causes a change in the refractive index and a higher resistance value than conventional compound semiconductors. The present invention utilizes the characteristics of the change in the refractive index and the securing of a high resistance value to realize the waveguide structure and the current confinement structure of the semiconductor optical device together.
INDUSTRIAL APPLICABILITY The present invention is extremely useful when applied to a semiconductor optical device, particularly to a waveguide structure and a current confinement structure of a semiconductor laser element.

[0008] A typical example of a compound semiconductor material containing phosphorus as a main element of the group V elements is AlGaInP. Further, GaInP or the like can be given as an example of such a material. A typical example of a compound semiconductor material containing nitrogen as a main element of the group V elements is Al.
GaInN. Further, Ga is an example of such a material.
N, AlGaN, GaInN and the like can be mentioned.

In applying the present invention, the forbidden band width of the semiconductor layer is preferably 2 eV or more.

The impurity to be introduced is typically zinc (Zn). Further, another example is magnesium (Mg).

In order to make the effect of the present invention effective,
The activation rate of the impurities is desirably 1% or less. The reason will be described later.

According to the present invention, even when a plurality of light emitting portions are provided on a single substrate, a semiconductor laser array in which crosstalk between stripes constituting each light emitting portion does not substantially cause a problem is realized with good reproducibility. I can do it.

Next, the main modes of the semiconductor optical device of the present invention are listed as follows.

(1) In a first embodiment of the present invention, a semiconductor laminate having a plurality of semiconductor layers has a stripe-like portion serving as an optical waveguide, and an impurity is introduced into at least a side portion of the stripe-like portion. By doing so, the stripe portion has a function of guiding light, and at least a part of the layered structure of the semiconductor laminate having the function of guiding light is formed of a compound semiconductor layer containing phosphorus and nitrogen. A semiconductor laser device.

According to the present invention, the region into which impurities are introduced on the side of the stripe-shaped portion has the function of guiding the light and the function of confining current. The present invention is very useful because it has two functions.

(2) A second embodiment of the present invention is directed to a first cladding layer having a first conductivity type, an active layer, and a second cladding having a second conductivity type, which are commonly formed on a semiconductor substrate. A semiconductor optical device having at least a layer and the following features.

(A) An impurity introduction region is provided in contact with a stripe region for guiding light.

(B) The impurity introduction region has the function of guiding the light.

(C) The impurity-doped region has a layer made of a compound semiconductor material containing at least one of phosphorus and nitrogen as a main group V element.

(D) The impurity-introduced region of the layer composed of the compound semiconductor material containing at least one of phosphorus and nitrogen as a main group V element is compared with the region into which the impurity is not introduced. As a result, a high resistance region is obtained. This high resistance region also functions as a current constriction.

As described above, the present invention can provide a high-performance semiconductor optical device at low cost without using a semiconductor region having both a light guiding function and a current confinement function, and without causing light loss in the optical waveguide region. .

(3) A third embodiment of the present invention is the first embodiment.
And the second conductivity type is an n-type. As a result, it has been difficult to manufacture a semiconductor laser device having a low operating current characteristic. However, according to the present invention, this type of semiconductor laser device can be provided. This is because current confinement can be performed in the n-type conductivity type semiconductor layer located on the opposite side of the active layer from the crystal growth substrate.

(5) The basics of the method for manufacturing a semiconductor laser device of the present invention are as follows.

That is, it comprises a plurality of semiconductor layers configured to have a compound semiconductor layer containing at least one of phosphorus and nitrogen in at least a part of a layered semiconductor laminate having a function of guiding light. Forming a semiconductor laminate having a compound semiconductor layer including a stripe-shaped portion serving as an optical waveguide in the semiconductor laminate, and an impurity on at least a side portion of the stripe-shaped portion, and at least the phosphorus and nitrogen. And a step of introducing until reaching.

The impurity introducing layer is made of the above-mentioned predetermined compound semiconductor material. It is important that the impurity is introduced from the outside after forming the semiconductor layer. Furthermore, after the introduction of the impurities, it is important not to use a process in which the process temperature is higher than a predetermined temperature.

The reason why the impurity introduction amount can be suppressed is that the solid solubility limit of a phosphorus-based or nitrogen-based semiconductor material for p-type impurities such as zinc and magnesium is small.
The increase in the resistance of the semiconductor layer is realized by a deep level formed by the self-compensation effect of the p-type impurity in these semiconductor materials. The carrier is hardly activated by the deep level.

Such a deep level is formed by steps such as impurity diffusion and ion implantation. However, this deep level disappears by heat treatment at a certain temperature or higher. Therefore, after introducing the impurities, it is necessary to keep the sample temperature within a range not exceeding the certain temperature.

On the other hand, in order to obtain the effect of mixing the superlattice, heat treatment at a certain temperature or higher is required. As a specific heat treatment temperature, when zinc is diffused into AlGaInP, the temperature is 450 to 500 degrees Celsius, when magnesium (Mg) is implanted into AlGaInP, 700 degrees from 500 degrees Celsius, and when Mg is implanted into AlGaN. Each range from 600 to 800 degrees Celsius was an appropriate heat treatment temperature.

(5) The semiconductor laser device of the present invention can easily realize an array-type semiconductor optical device or an array-type semiconductor laser device having a plurality of light-emitting portions or laser light-emitting portions in a single device. Enables voltage drive. Negative voltage driving is a driving method capable of higher-speed modulation.

(6) In the case of forming an array type semiconductor optical device, a step is provided on a substrate on which each light emitting section is mounted, and each light emitting section can be mounted on each plane defined by each step. . In this case, it is also possible to mount a plurality of light emitting units, for example, two light emitting units, provided on each stage.

Incidentally, as the means for returning light of the semiconductor laser device described so far, those used in the conventional semiconductor laser device can be used. That is, Fabry
Perot structure (Fabry-Perot resonance)
r), distributed feedback structure (DFB: distributed)
feedback), Bragg reflector structure (DBR: d
istributed Bragg reflecto
r) can be used.

Further, various means used in other semiconductor laser devices, such as a protective film or a reflective film for protecting a crystal end face, or a buffer means for good crystal growth, may be used. Use is optional.

[0033]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Before describing the embodiments of the present invention, the facts that led to the present invention will be described.

In the aforementioned semiconductor laser device using the compound semiconductor layer according to the present invention, for example, a compound semiconductor material containing phosphorus as a constituent such as AlGaInP or a compound semiconductor material containing nitrogen as a constituent such as AlGaInN. After the formation of the semiconductor multilayer structure, the impurity concentration is 5 × 1 even if impurities are introduced from the outside.
It remained below 0 ¹⁸ cm ^-3 . Moreover, the activation rate of such externally introduced impurities is very low,
It has been found that the carrier concentration in this region is generally less than 1 × 10 ¹⁶ cm ⁻³ . The present invention applies such a phenomenon to the formation of a waveguide structure and the formation of a current confinement structure by introducing impurities when a semiconductor laser device is manufactured.

FIG. 2 is a diagram showing the impurity concentration, the hole concentration, and the distribution from the surface of the substrate to the depth. The semiconductor material is AlGaInP. The impurity concentration was measured by secondary ion mass spectrometry, while the hole concentration was calculated from the capacity-voltage characteristics of the material layer. In FIG. 2, the horizontal axis represents the depth from the substrate surface, and the vertical axis represents the concentration of each element and carrier. The secondary ion intensity is graduated on the vertical axis on the right side. The impurity concentration and the like were calculated based on the intensity.

In the example of FIG. 2, the impurity region is formed to a depth of about 2.3 microns from the surface of the base. From this figure, the impurity concentration of zinc in this impurity region is 5 × 1
^{Despite being} from 0 ¹⁷ cm ^-3 to 2 × 10 ¹⁸ cm ^-3 , the hole concentration generated by the activation of this impurity (FIG. 2 shows h
(denoted as ole) is found to be kept at 1 × 10 ¹⁶ cm ⁻³ or less. A similar situation occurs in the semiconductor material according to the present invention. The relationship between the impurity concentration and the carrier concentration has the same tendency as in the example of FIG. 2 in the compound semiconductor material according to the present invention.

As described above, the increase in the resistance of the impurity region of the compound semiconductor material according to the present invention is realized by a deep level formed by the self-compensation effect of the p-type impurity in these semiconductor materials.

<First Embodiment> A first embodiment of the present invention will be described with reference to FIGS. This example is an example of a semiconductor laser device. FIG. 3 is a cross-sectional view showing a state in which zinc is diffused into a predetermined semiconductor laminate. FIG. 4 is a cross-sectional view of a semiconductor laser device manufactured using the semiconductor laminate shown in FIG. FIG.

The first embodiment is a semiconductor laser device having the following configuration. That is, a cladding layer formed on a substrate crystal of the first conductivity type and made of a semiconductor of the first conductivity type and a semiconductor of a direct transition type having a narrower forbidden band width than the first cladding layer. And a stripe-shaped portion formed of a layered semiconductor crystal including at least a cladding layer formed of a semiconductor of the second conductivity type having a wider band gap than the active layer, and serving as an optical waveguide having the layered structure. Is a semiconductor laser having a function of guiding light to a stripe portion by introducing an impurity into a region except for the semiconductor laser.

First, a double heterostructure, which is the basis of a semiconductor laser device, is manufactured by using a well-known metal organic chemical vapor deposition method. 3 and 4, the same reference numerals indicate the same members. In these figures, reference numeral 101 denotes a p-type GaAs substrate, and the plane orientation of the surface is a (100) plane. This Ga
The following layers are sequentially formed on the As substrate 101. They include (1) a p-type cladding layer 102 (Zn-doped, impurity concentration: p = 7 × 10 ¹⁷ cm) made of Al _0.5 Ga _0.5 As.
^-3 , thickness: 1.8 μm), (2) multiple quantum well active layer 1
03, (3) a first n-type clad layer 104 made of Al _0.5 Ga _0.5 As (Se-doped, impurity concentration: n = 1 × 1
0 ¹⁸ cm ⁻³ , thickness: 0.2 μm), (4) (Al _0.7 G
a _0.3 ) Second n-type cladding layer 1 made of _0.5 In _0.5 P
05 (Se-doped, impurity concentration: n = 1 × 10 ¹⁸ c
m ⁻³ , thickness: 1.5 μm), (5) n-type Ga _0.5 In _0.5
P layer 106 (Se-doped, impurity concentration: n = 1 × 10 ¹⁸
cm ⁻³ , thickness: 20 nm) and (6) n-type GaAs cap layer 107 (Se-doped, impurity concentration: n = 1 × 1)
0 ¹⁹ cm ^-3 , thickness: 20 nm). The multiple quantum well active layer is composed of four Al _0.1 Ga _0.9 As well layers 108.
(Thickness: 7 nm) and five layers of Al _0.3 Ga _0.7 As sandwiching it.
It is composed of a barrier layer 109 (thickness: 4 nm).

Diffusion of zinc (Zn) is performed on a part of the semiconductor laminate thus prepared. First, a silicon dioxide (SiO ₂ ) film 110 is formed on the n-type GaAs cap layer 107 using a normal chemical vapor deposition method. Then, the SiO ₂ film 110 is processed into a stripe shape having a width of about 5 μm by using photolithography technology. The longitudinal direction of the stripe is the optical axis direction of the optical resonator. In the present embodiment, a case is shown in which a cross-sectional structure has two stripes in order to form an array-type semiconductor laser device having a plurality of semiconductor lasers on the same semiconductor chip. The interval is 20 μm. Using this SiO ₂ film 110 as a mask, the n-type GaAs cap layer 107 is etched (etched). It should be noted that reference numerals 107 and 110 in the drawings are cross-sectional views of the layers after the processing, the cap layer, and the SiO ₂ layer.

A ZnO film 111 is deposited on the thus prepared semiconductor substrate by sputtering. This Z
The nO film 111 is a diffusion source of zinc.

The wafer on which the semiconductor laminate was formed was heated in a nitrogen atmosphere from 500 ° C. to 600 ° C. to diffuse zinc from the ZnO film 111. Further, after removing the diffusion source, a heat treatment was performed at about 500 degrees Celsius in order to progress the mixed crystal formation by the diffused impurities.

FIG. 3 shows a sectional structure of the wafer in this state. It should be noted that FIG. 2 also shows a partially enlarged view of the multiple quantum well layer. The shaded area indicated by reference numeral 112 in FIG. 3 is a zinc diffusion region. The depth of this zinc diffusion region is preferably such that it extends over the cladding layer on the side closer to the substrate constituting the semiconductor laser.

In conventional AlGaAs-based semiconductors, the impurity diffusion region subjected to such zinc diffusion is generally a low-resistance layer having a high hole concentration. Therefore, in the conventional material system and element structure, it is necessary to separately form an additional current confinement structure so that no current flows in this region.

However, by applying the present invention, the compound semiconductor layer region 116 containing phosphorus as a main group V element in the region in which zinc is diffused can secure a high resistance value together with the change in the refractive index of the material. I can do it. Therefore, it is not necessary to provide an additional current confinement structure. The zinc diffusion region constitutes a waveguide and a current confinement layer.

That is, the region of the first cladding layer 105 made of n-type (Al _0.7 Ga _0.3 ) _0.5 In _0.5 P containing phosphorus as a main group V element is diffused with zinc, thereby increasing the resistance. Such a high resistance (Al _0.7 G
The a _0.3 ) _0.5 In _0.5 P layer recovers the carrier concentration when subjected to a heat treatment at a temperature of 550 ° C. or more after the diffusion of zinc. Therefore, in the process after the diffusion of zinc for the purpose of forming the impurity region according to the present invention, the process temperature needs to be 550 ° C. or less.

Moreover, in a semiconductor material containing phosphorus as a main V element, the amount of zinc introduced by diffusion can be suppressed to about one tenth as compared with a semiconductor material containing arsenic as a main V element. Therefore, the amount of zinc introduced into the active layer is significantly reduced as compared with the case where zinc is directly diffused. In this manner, both the loss and the problem due to free carrier absorption of the zinc diffusion layer, which are problems in the conventional structure, are solved. Furthermore, in this structure, the diffusion rate of zinc in the phosphorus-based semiconductor is about four times faster than that of the arsenic-based semiconductor, so that the position of the diffusion front can be controlled with good reproducibility even from the wafer surface. there were.

After removing the ZnO film 111 as an impurity diffusion source, an n-side electrode 113 made of an Au.Ge alloy is provided by an electron beam evaporation method in vacuum.
The p-side electrode 114 made of an Au—Zn alloy is
Was provided. In order to allow current to be independently injected into the two stripes, a groove 115 removed from the n-side electrode 113 to the multiple quantum well active layer 103 is formed over a width of about 10 μm between the stripes to electrically connect both stripes. separated. FIG. 4 is a view showing a state in which the groove is formed. Cleave a wafer of such a structure to a length of about 250 μm,
The end face was covered with a multilayer film of SiO ₂ and a-Si having a reflectance of about 64% to form a laser chip.

When such a semiconductor laser chip was bonded to a Cu stem with its bonding surface facing upward and energized, both laser stripes oscillated continuously at room temperature at a wavelength of 780 nm and a threshold current of about 10 mA. Since the operating current is small, the bonding surface is assembled upward, and the stripe interval is 20μ.
Despite being close to m, the fluctuation of the light output of the other stripe due to the blinking of one stripe was 5% or less. Further, in the semiconductor optical device of this example, a so-called minus drive in which the p-type substrate is shared can be performed. Therefore, this embodiment also has an advantage that a high-speed and inexpensive driving power supply can be used.

<Second Embodiment> A second embodiment is an example in which a plurality of light emitting units of the first embodiment are mounted on a single substrate. Since the details of each light emitting unit are the same as in the first embodiment,
Here, the details are omitted.

In this example, each light-emitting portion is provided on each flat portion divided by a step. However, it is of course possible to provide a plurality of light-emitting portions on a single plane substrate.

FIG. 5 is a cross-sectional view of a principal part of the semiconductor laser device of the present embodiment taken along a plane intersecting the optical axis, and the relationship between the track and the laser spot is illustrated below. The semiconductor substrate 101 has two steps 209, and three planes 2 having different heights.
10, 211, and 212. One plane 210
, Two light emitting portions are formed as a laser array 213. On the other two planes 211 and 212, 214 and 215 light emitting portions are formed, respectively.

The semiconductor layer 102 is a first cladding layer,
The semiconductor layer 103 is an active layer, and the semiconductor layer 104 is a second clad layer. As described above, the specific configurations of these laser emitting units are the same as those in the first embodiment.

The semiconductor optical device having such a configuration is most suitable as a light source for an optical information processing device, for example, a high-speed optical disk. This is an example in which four semiconductor laser element units are integrated for this purpose. In this apparatus, the spot of the semiconductor laser light is configured so that the substrate surface of the semiconductor laser is inclined by about 1 to 3 degrees with respect to the optical disk.

The relationship between the tracks on the optical disc and each light emitting section is as follows. In this figure, two tracks 216, 2
17 are illustrated. Then, two irradiation spots 218 and 219 and a light emitting unit 214 are output from the laser light emitting unit 213.
Corresponds to the irradiation spot 220, and from the light emitting unit 214 corresponds to the irradiation spot 221.

Two laser sections 213 for reading information are formed, for example, at an interval of about 10 μm. The average output of these light emissions is both driven at, for example, 5 mW. However, these are driven at different frequencies, and the optical signal of each laser unit can be distinguished by the frequency filter circuit. On the other hand, the two laser portions 214 and 215 for writing information are formed on planes (211 and 212) which are higher by 1 μm and 2 μm, respectively, than the laser portions for reading. The distance is about 100 μm and about 2 μm from the reading laser unit.
It is 00 μm.

Since the substrate surface that is far from the read laser unit is formed oblique to the track, the same track is scanned before the read laser unit. Since the two reading laser units are used in this manner, the reading speed of the present device is twice as high as that of a normal device. Further, since a confirmation scan at the time of writing is not required, the writing speed is quadrupled.

Further, in the present apparatus, the problem of thermal mutual interference of the semiconductor laser elements can be solved by the following method. That is, in the present apparatus, the problem of thermal mutual interference between the semiconductor laser element portions does not occur, and the read laser portion driven with a constant average output is arranged at a short distance. This is because the semiconductor laser portions for use can be formed at a large distance.

Next, an example of the configuration of an optical information processing system applied with the present semiconductor laser device will be described.

As an example of the optical information processing apparatus of the present invention, there can be mentioned an optical recording apparatus such as an optical disk apparatus such as a compact disk (CD) and a digital video disk (DVD). An optical disc device is an optical recording device having at least a light source for irradiating a recording medium with light and a detector for detecting reflected light from the recording medium. Needless to say, there is an optical information processing apparatus that performs recording by changing the state of a part of a recording medium by light.

FIG. 6 is a basic configuration diagram showing an example of an optical disk device. 21 is a disk provided with an optical recording medium for optical recording, 22 is a motor for rotating the disk,
23 is an optical pickup, and 27 is a control unit for controlling these. The optical pickup 23 includes a lens system 24, a light source 25 such as a semiconductor laser device, and a photodetector 26.

Various reports have been made on general matters of such optical disk devices, but they will be briefly described. Depending on the type of recording material, optical disc devices are roughly classified into read-only type (R
OM type), write-once type, and rewritable type. The reproduction of information in the example of FIG. 6 is performed by optically reading a change in the reflected light from the minute holes (the state change portion of the recording medium) recorded on the disk 21 with the photodetector 26. Incidentally, an ordinary optical recording medium can be used.

In the case of the read-only type, the recording information is recorded on the recording medium in advance, and examples of the read-only type recording medium include aluminum and plastic.

In the case of recording, the laser light is focused on a recording medium on the disk to a fine light spot, and the laser light is modulated according to the information to be recorded, thereby thermally changing the state of the recording material. Record in rows. This recording is performed while the disk is rotated (moved) by a motor. The light source of the present invention can be used for such a light source.

It is convenient to apply the above-described semiconductor laser device to the light source of such an optical disk device.

<Embodiment 3> A second embodiment of the present invention will be described with reference to FIGS. The schematic configuration is the same as that of the first embodiment. FIG. 7 is a cross-sectional view showing a state where zinc is diffused into a predetermined semiconductor laminate. FIG. 8 is a cross-sectional view of a semiconductor laser device manufactured using the semiconductor laminate shown in FIG. FIG. In this example,
This is an example in which a current confinement region is formed in both the p-type and n-type semiconductor layer regions by using the phenomenon of high resistance due to diffusion of zinc or the like of the present invention. Due to the two current constrictions, an effect of further reducing the operation can be obtained as compared with one of the current constrictions.

First, a double heterostructure, which is the basis of a semiconductor laser device, is manufactured by using a well-known metal organic chemical vapor deposition method. 7 and 8, the same reference numerals indicate the same members. In the figure, 101 is a p-type GaAs substrate,
The plane orientation of the p-type GaAs substrate 101 is the (100) plane. The following layers are sequentially crystal-grown on the substrate 101. They include (1) a first Al _0.5 Ga _0.5 As
P-type cladding layer 201 (Zn-doped, impurity concentration: p
= 7 × 10 ¹⁷ cm ⁻³ , thickness: 1.5 μm) (2) p-type (Al _0.7 Ga _0.3 ) _0.5 In _0.5 P layer 202 (Zn-doped, impurity concentration: p = 7 × 10 ¹⁷ cm ⁻³⁾ , Thickness: 0.1
μm), (3) a second p-type cladding layer 203 made of Al _0.5 Ga _0.5 As (Zn-doped, impurity concentration: p = 7 ×
(10 ¹⁷ cm ⁻³ , thickness: 0.3 μm), (4) multiple quantum well active layer 103, (5) first n-type cladding layer 104 of Al _0.5 Ga _0.5 As having a thickness of 0.2 μm, ( 6)
(Al _0.7 Ga _0.3 ) _0.5 In _0.5 P
μm second n-type cladding layer 105, (7) n-type Ga _0.5
An In _0.5 P layer 106 and (8) a cap layer 107 made of n-type GaAs having a thickness of about 0.2 μm. The multiple quantum well active layer is composed of four Al _0.1 Ga _0.9 As well layers 108.
(Thickness: 7 nm) and five layers of Al _0.3 Ga _0.7 As1 sandwiching it.
09 (4 nm thick).

Diffusion of zinc (Zn) is performed on a part of the semiconductor laminate thus prepared. First, SiO _{2 is formed} on the n-GaAs cap layer 107 by using a normal chemical vapor deposition method.
A film 110 is formed, and this S
The iO ₂ film 110 is processed into a stripe having a width of about 5 μm.
The longitudinal direction of the stripe is the optical axis direction of the optical resonator. 7 and 8 are cross-sectional views of each layer after the processing.

Using this SiO ₂ film 110 as a mask, n
The cap layer 107 made of type GaAs is etched. Next, after the ZnO film 111 is deposited by a sputtering method, zinc is diffused from the ZnO film 111. This zinc diffusion causes the semiconductor wafer to be exposed to 50 degrees Celsius in a nitrogen atmosphere.
This was performed by heating from 0 to 600 degrees. FIG. 3 shows a sectional structure of the wafer in this state. It should be noted that FIG. 2 also shows a partially enlarged view of the multiple quantum well layer.

In FIG. 7, a hatched portion indicated by reference numeral 112 is a zinc diffusion region. The depth of this zinc diffusion region is preferably such that it extends over the cladding layer on the side closer to the substrate constituting the semiconductor laser.

In this example, (Al _0.7 Ga _0.3 ) _0.5 In _0.5
P-type second n-type cladding layer 105 and p-type (A
The above-mentioned zinc diffusion region is provided in the l _0.7 Ga _0.3 ) _0.5 In _0.5 P layer 202. This zinc diffusion region plays a role of current confinement. Hereinafter, this point will be described.

In an AlGaAs-based semiconductor material, a region where such zinc diffusion is performed becomes a low-resistance layer having a high hole concentration. Conventionally, it has been necessary to separately form a current confinement structure so that current does not flow in this region. However, in the structure of the present invention, phosphorus is mainly V
The second n-type cladding layer 105 made of (Al _0.7 Ga _0.3 ) _0.5 In _0.5 P containing as a group element has a higher resistance rather than zinc diffusion. Therefore, the structure of the present invention eliminates the need to provide an additional current confinement structure. In addition, in a semiconductor material containing phosphorus as a main V element, the amount of zinc introduced by diffusion is reduced to about one tenth as compared with a semiconductor material containing arsenic as a main V element, so that it is introduced into the active layer. The amount of zinc is also significantly less than when zinc is directly diffused. Therefore, both the loss and the problem due to the free carrier absorption of the zinc diffusion layer, which are problems in the conventional structure, are solved. Furthermore, since the diffusion rate of zinc in the phosphorus-based semiconductor material in this structure is about four times faster than that of the arsenic-based material, it is possible to control the position of the diffusion front with good reproducibility even from the wafer surface. there were.

In the present embodiment, the p-type AlGaInP layer (the specific example is (Al _0.7 Ga _0.3 ) _0.5 In _0.5 P layer) 202 provided on the p-type cladding layer side is similarly formed by zinc diffusion. In order to increase the resistance, current confinement is possible in both the p-type and n-type cladding layers. Therefore, a further effect of reducing the operating current was obtained. Such a high-resistance AlGaInP layer (this specific example is (Al _0.7 Ga
_0.3 ) _0.5 In _0.5 P layer) is 550 ° C. after diffusion.
If the heat treatment step is performed at a temperature equal to or higher than the temperature, the carrier concentration is recovered. Therefore, in the steps after the formation of the AlGaInP layer with increased resistance, the process temperature is set to 5 degrees Celsius.
It was necessary to set it to 50 degrees or less.

After the ZnO film 111 is removed, the n-side electrode 1 made of an Au.Ge alloy is deposited by electron beam evaporation in vacuum.
13 on the back surface of the GaAs substrate 101,
A p-side electrode 114 made of Au / Zn alloy was provided. A groove 115 was formed at the center of the two stripes over a width of about 10 μm to electrically separate the two stripes from each other so that currents could be independently injected into the two stripes. This groove was formed by removing from the n-side electrode 113 to the multiple quantum well active layer 103. FIG. 8 is a sectional view showing this state.

A wafer having such a structure is about 250 μm long.
c to form a laser chip. The end face of the semiconductor laser device is covered with a multilayer film of SiO ₂ and a-Si (amorphous silicon), and the reflectance of the multilayer film is about 64%.

The semiconductor laser chip was mounted on a Cu stem by bonding the bonding surface of the semiconductor laser chip upward.

When this semiconductor laser device was energized,
Both laser stripes oscillated continuously at room temperature at a wavelength of 780 nm and a threshold current of about 8 mA. Since the operating current was small, the bonding surface was assembled upward, and the flash output of one stripe affected the light output of the other stripe by 5% or less even though the stripe interval was close to 20 μm. .

In addition, the present semiconductor laser device has an advantage that a minus drive using a common p-type substrate can be performed, and a high-speed and inexpensive drive power supply can be used.

<Fourth Embodiment> A fourth embodiment of the present invention will be described with reference to FIGS. This example is an example of a semiconductor laser device. 9 is a cross-sectional view showing a state in which zinc is diffused into a predetermined semiconductor laminate, FIG. 10 is a plan view showing an arrangement of stripes, and FIG. 11 is a semiconductor laser device manufactured using the semiconductor laminate shown in FIG. FIG. 3 is a cross-sectional view taken along a plane crossing the optical axis of the laser light.

First, a double heterostructure, which is the basis of a semiconductor laser device, is manufactured using metal organic chemical vapor deposition.
9 and 10 indicate the same members.
In the figure, reference numeral 301 denotes an n-type GaAs substrate.
The plane orientation of the surface of the type GaAs substrate 301 is the (100) plane. The following layers are sequentially laminated on this substrate. They are (1) n-type Al _0.5 Ga _0.5 As clad layer 302
(Se doping, impurity concentration: n = 1 × 10 ¹⁸ cm ⁻³ , thickness: 1.5 μm), (2) multiple quantum well active layer 103,
(3) p-type Al _0.5 Ga _0.5 As clad layer 303 (Zn
Doping, impurity concentration: p = 7 × 10 ¹⁷ cm ⁻³ , thickness:
1.6 μm), and (4) p-type GaAs cap layer 3
04 (Zn-doped, impurity concentration: p = 1 × 10 ¹⁹ c
m ^-3 , thickness: 0.2 μm). The multiple quantum well active layer is composed of four Al _0.1 Ga _0.9 As well layers 108 (thickness: 7 n).
m) and five layers of Al _0.3 Ga _{0.7 As} 109 (thickness: 4 nm) sandwiching it.

A stripe is formed on the semiconductor wafer thus prepared for forming a light emitting portion in the same manner as in the previous embodiments. That is, a silicon dioxide film 305 is provided using a vapor phase chemical deposition method, and a stripe in which two stripes are arranged in parallel is formed on the silicon dioxide film 305 using a photolithographic technique. FIG. 6 shows a planar arrangement of silicon dioxide stripes. In FIG. 10, the semiconductor substrate is 30.
0, the silicon dioxide stripe is 305. Note that FIG.
2 shows a partially enlarged view of the multiple quantum well layer in a circle.

Further, the silicon dioxide film 3 of such a wafer
A part of the p-type GaAs cap layer 304 and a part of the p-type cladding layer 303 in a region not covered with 05 were etched using a sulfuric acid-based etchant. Next, using the silicon dioxide film 305 as a selective growth mask, the n-type Ga _0.5 In _0.5 P current block layer 306 was selectively grown by metal organic chemical vapor deposition.

After removing the silicon dioxide film 109 used as the mask, the ZnO film 1 serving as a zinc diffusion source is
Eleven deposits were made. The zinc was diffused from the ZnO film 111 by heating the sample from 500 ° C. to 600 ° C. in a nitrogen atmosphere. The zinc was diffused so as to penetrate the active layer in a region outside the stripe. FIG. 9 shows a sectional structure of the wafer in this state.

In this structure, the n-type Ga _0.5 In _0.5 P current block layer 306 containing phosphorus as a main group V element has a high resistance due to zinc diffusion, so that there is no need to provide an additional current confinement structure. Moreover, in a semiconductor containing phosphorus as a main V element, the amount of zinc introduced by diffusion is reduced to about one tenth as compared with a semiconductor containing arsenic as a main V element. Is significantly reduced as compared with the case where zinc is directly diffused. For this reason, both the loss and the problem due to the free carrier absorption of the zinc diffusion layer, which are problems in the conventional structure, are solved.

In the present structure, the diffusion rate of zinc in the arsenic-based semiconductor is slower than that of the phosphorus-based semiconductor by about 1/4, so that G
In the stripe portion where the a _0.5 In _0.5 P current block layer 306 does not exist, the diffusion stops in the p-type cladding layer 303, which has the effect of reducing the series resistance of the device. p
It was possible to control the position of the diffusion front with good reproducibility even from the diffusion from the wafer surface.

After removing the ZnO film 111 serving as an impurity diffusion source, an n-side electrode 114 made of an Au.Ge alloy is provided by an electron beam evaporation method in a vacuum, and the Au. P-side electrode 1 made of Zn alloy
13 were provided. A width of about 10 at the center of the two stripes so that current injection can be performed independently on the two stripes.
Grooves 115 were removed from the p-side electrode 114 to the multiple quantum well active layer 103 over a length of μm to electrically separate both stripes. FIG. 11 shows a sectional structure of the semiconductor laser wafer formed by the above steps.

A wafer having such a structure is about 250 μm long.
c to form a laser chip. The end face of the semiconductor laser is covered with a multilayer film of SiO ₂ and a-Si having a reflectance of about 64%.

When the semiconductor laser chip of this example was bonded to a Cu stem with the bonding surface facing upward and energized, both laser stripes oscillated continuously at room temperature at a wavelength of 780 nm and a threshold current of about 10 mA. Because the operating current is small,
The light output of the other stripe was fluctuated by 5% or less due to the blinking of one stripe, although the bonding surface was assembled upward and the stripe interval was close to 20 μm.

<Embodiment 5> A fourth embodiment of the present invention will be described with reference to FIGS. This example is an example of a semiconductor laser device. FIG. 8 is a cross-sectional view showing a state in which zinc is diffused into a predetermined semiconductor laminate. FIG. 13 is a plane intersecting the optical axis of laser light of a semiconductor laser device manufactured using the semiconductor laminate shown in FIG. FIG.

A double heterostructure, which is the basis of a semiconductor laser device, is manufactured by using a metal organic chemical vapor deposition method. FIG.
In FIG. 13 and FIG. 13, the same symbols indicate the same members. In the figure, 101 is a p-type GaAs substrate,
The plane orientation of the surface of the As substrate 101 is the (100) plane.
The following layers are sequentially formed on the GaAs substrate. These are (1) p-type In _0.5 (Ga _0.3 Al _0.7 ) _0.5 P cladding layer 401 (Mg doped, impurity concentration: p = 1 × 10 ¹⁸⁾
cm ⁻³ , thickness: 1.8 μm), (2) undoped In
Optical guide layer 402 made of _0.5 (Ga _0.7 Al _0.3 ) _0.5 P
In _0.55 Ga _0.45 P active layer 403 sandwiched by
(3) n-type In _0.5 (Ga _0.3 Al _0.7 ) _0.5 P clad layer 404 (Si-doped, impurity concentration: p = 1 × 10 ¹⁸ cm)
^-3 , thickness: 1.5 μm), (4) (Ga _0.7 Al _0.3 )
An optical waveguide layer 4041 in which five layers of _0.5 In _0.5 P (thickness: 3 nm) and Ga _0.5 In _0.5 P (thickness: 3 nm) are stacked;
(5) n-type In _0.5 (Ga _0.3 Al _0.7 ) _0.5 P cladding layer 404 (Si-doped, impurity concentration: p = 1 × 10 ¹⁸ cm)
^-3 , thickness: 1.5 μm) (6) n-type In _0.5 Ga _0.5 P layer 405 (Si-doped, impurity concentration: p = 1 × 10 ¹⁸ cm)
^-3 , thickness: 20 nm), and (7) n-type GaAs cap layer 107.

The active layer may have a constant composition such as a double hetero structure, or may have a structure having energy modulation such as a multiple quantum well structure. In the case of a constant composition, it must be formed so as to produce a periodic composition fluctuation of In and Ga during crystal growth, that is, a so-called natural superlattice. In this embodiment, In _0.55 Ga _0.45 crystal was grown under the condition that a natural superlattice was formed.
P was used as the active layer.

Next, Zn is diffused into a part of the wafer. In this example, a zinc ion implantation method was used.

An SiO ₂ film 110 is formed on the wafer prepared by the above steps by a usual thermal chemical deposition method for about 200 hours.
nm deposited. This SiO ₂ film 110 and n-GaAs
The cap layer 107 has a width of 5 using photolithographic technology.
It is removed leaving a stripe shape of μm to 10 μm. Next, zinc ions are implanted at about 0.3 μm using the SiO ₂ film 110 and the n-GaAs cap layer 107 as a mask. Such a wafer is placed in nitrogen at 500 degrees Celsius to 60 degrees Celsius.
By heating to 0 degrees, light zinc was diffused from the zinc-implanted layer 406.

In this structure, n- (Al _0.7 Ga _0.3 ) _0.5 containing phosphorus as a main group V element as in the first embodiment.
The resistance of the In _0.5 P cladding layer 404 is rather increased by zinc diffusion. Therefore, there is no need to provide an additional current confinement structure as conventionally used.

After removing the ZnO film 111 as an impurity diffusion source, an n-side electrode 113 made of an Au.Ge alloy is provided by an electron beam evaporation method in a vacuum, and the Au. A p-side electrode 114 made of a Zn alloy was provided. The width of the central part of the two stripes is about 1 so that the current can be independently injected into the two stripes.
Grooves 115 were formed over 0 μm from the n-side electrode 113 to the multiple quantum well active layer 103 to electrically separate both stripes. FIG. 13 shows a sectional structure of the semiconductor laser device formed as described above. This cross section is a cross-sectional view of a plane crossing the optical axis of the laser. A wafer having such a structure was cleaved to a length of about 250 μm to form a laser chip. The end face of the semiconductor laser device is covered with a multilayer film of SiO ₂ and a-Si having a reflectivity of about 64%.

When such a semiconductor laser chip was bonded to a Cu stem with its bonding surface facing upward and energized, continuous oscillation at room temperature was performed at a wavelength of 680 nm and a threshold current of about 50 mA. The maximum light output is about 300 mW, and the light output is 100 mW.
A continuous operation of 5000 hours or more at mW was possible.

<Sixth Embodiment> The structure of a semiconductor laser device according to a sixth embodiment will be described with reference to FIGS. In this example, there is no need to provide a groove for electrical isolation between the stripes of the two laser oscillation units.

FIG. 14 is a plan view showing the plane arrangement of the stripes of the optical resonator and the impurity diffusion source, FIG. 15 is a sectional view showing a state where zinc is diffused into a predetermined semiconductor laminate, and FIG. 16 is shown in FIG. It is sectional drawing in the surface which intersects with the optical axis of the laser beam of the semiconductor laser device manufactured using the semiconductor laminated body.

A double heterostructure is manufactured by using a metal organic chemical vapor deposition method which is a basic semiconductor laser device. FIG.
16 and FIG. 16 indicate the same members. In the figure, reference numeral 501 denotes an n-type GaAs substrate.
The plane orientation of the aAs substrate 501 is from (100) plane to (11).
It is shifted about 7 degrees in the 0) direction. The following layers were sequentially crystal-grown on this substrate. These are (1) n-type (Al _0.7 G
a _0.3 ) _0.5 In _0.5 P cladding layer 502 (Se-doped, impurity concentration: p = 1 × 10 ¹⁸ cm ⁻³ , thickness: 1.8 μm)
m), (2) Multiple quantum well active layer 503, p-type (Al _0.7
Ga _0.3 ) _0.5 In _0.5 P cladding layer 504 (Zn doped, impurity concentration: p = 7 × 10 ¹⁷ cm ⁻³ , thickness: 1.6)
μm), and (3) p-type GaAs cap layer 505
(Zn doping, impurity concentration: p = 1 × 10 ¹⁹ cm ⁻³ , thickness: 0.2 μm). The multiple quantum well active layer is composed of four Ga _0.5 In _0.5 P well layers 506 (thickness: 7 nm) and five (Al _0.7 Ga _0.3 ) _0.5 In _0.5 P barrier layers 5 sandwiching the Ga _0.5 In _0.5 P well layer 506.
07 (4 nm thick).

Next, Zn is diffused into a part of the wafer. First, the p-type GaAs cap layer 505 is processed into a stripe shape having a width of 25 μm as shown in FIG. 10 by using photolithography. These stripes have a slit region 509 at the center where the p-type GaAs cap layer 505 is removed. A semiconductor laser stripe is formed in this portion. The slit region 509 from which the p-type GaAs cap layer 505 has been removed is set to 5 μm, which is 2 μm wider than the stripe width of 3 μm of the semiconductor laser oscillation portion, in consideration of a slight spread of the diffusion region. The spacing between the unpaired stripes is determined by the necessary spacing between the stripes of the semiconductor laser oscillating portion. It is desirable that the spacing be at least 5 μm or more in order to perform zinc diffusion in this portion in a later step.

Next, Z of the impurity diffusion source is
An nO film 111 is deposited. After this deposition, the ZnO film 111 is processed by photolithography so as to remain only on both sides of the stripe of the p-type GaAs cap layer 505 as shown in FIG.

The wafer was heated from 500 ° C. to 600 ° C. in nitrogen to diffuse zinc from the ZnO film 111.

In the region where the ZnO film 111 remains, zinc is directly diffused from the ZnO film 111 and the zinc concentration is about 5 × 10 ¹⁸
A zinc diffusion region 112 of cm ⁻³ is formed. In this region, crystal defects occur due to the high concentration of impurity diffusion, and the light emission intensity of the photoexcitation light emission is reduced to about 1/100.

On the other hand, in the region where the n-type GaAs cap layer 505 exists, direct diffusion of zinc from the diffusion source does not occur. However, in the region adjacent to the zinc diffusion region, re-diffusion of the impurity induced by the high-concentration doped region occurs, causing the superlattice to be mixed and a short wavelength region to be formed. Such re-diffusion of impurities spreads laterally at a speed of about 5 μm per minute along a certain region of the n-type GaAs cap layer 505, so that about 1 μm after zinc diffusion in the diffusion region reaches the active layer. The wavelength shortening region 508 is n-type Ga
It extends all over the bottom of the As cap layer 505.

Such a wavelength shortening region is caused not by an impurity introduced from the outside but by a mixed crystal of a superlattice due to re-diffusion of an impurity originally doped in the cladding layer. Therefore, unnecessary increase of the impurity concentration does not occur. Therefore, the loss due to the impurity absorption in the window region and the decrease in the light emission intensity of the photoexcitation light emission do not occur.

Through the above-described steps, the superlattice structure of the active layer in the region where the ZnO film 111 serving as the impurity diffusion source is provided and in the region where the n-type GaAs cap layer 505 is left are mixed crystal, and the band gap is widened. . Therefore, an optical waveguide is formed in a gap portion of the n-type GaAs cap layer 505 where the forbidden band width does not change.

In the present embodiment, the region in which zinc is directly diffused has a high resistance, so that there is no need to provide a groove for electrical isolation between the two stripes. As a result, the number of manufacturing steps of the semiconductor laser element is reduced, and the defect of cleavage caused by the groove generated in the element separated by the conventional groove is reduced. Further, the structure of this example has an advantage that the shape of the insulating region can be easily controlled as compared with the case where the groove is formed, and the interval between the laser light emitting portions can be reduced.

Further, near the end face of the semiconductor laser device, the slit region 50 of the n-type GaAs cap layer 505 is formed.
Since 9 is interrupted, in this region, a mixed crystal occurs also in a portion to be a laser stripe, and the forbidden band width is widened. As a result, a so-called window structure in which the forbidden band width of the active layer at the end face is larger than the energy of photons of the laser beam can be formed at the same time, and there is also an effect of preventing the end face from being destroyed.

After the impurity diffusion source ZnO film 111 is removed, p-side electrodes 114 electrically connected to the respective stripes are formed. Further, on the back surface of the GaAs substrate 101, an Au—Zn alloy is formed. N-side electrode 113 was provided.

The semiconductor laser device of this example has a wavelength of 630 nm.
m, continuous oscillation at room temperature with a threshold current of about 50 mA, a maximum optical output of about 200 mW, and 500
Continuous operation for 0 hours or more was possible.

<Seventh Embodiment> The structure of a semiconductor laser device according to a seventh embodiment will be described with reference to FIGS. In this example, there is no need to provide a groove for electrical isolation between the stripes of the two laser oscillation units.

FIG. 17 is a sectional view showing a state where zinc is diffused into a predetermined semiconductor laminate. FIG. 18 intersects the optical axis of laser light of a semiconductor laser device manufactured using the semiconductor laminate shown in FIG. It is sectional drawing in the surface which performs.

A double hetero structure is manufactured by using a metal organic chemical vapor deposition method which is a basic of a semiconductor laser device. FIG.
18 and FIG. 18, the same reference numerals indicate the same members. In the figure, reference numeral 601 denotes a p-type GaN substrate. The plane orientation of the GaN substrate 601 is the (1100) plane. The following layers were sequentially crystal-grown on this substrate. They are,
(1) p-type Ga _0.7 Al _0.3 N cladding layer 602 (Mg doped, p = 1 × 10 ¹⁸ cm ⁻³ , thickness: 1.8 μm),
(2) a light guide layer 603 made of undoped GaN;
(3) In _0.55 Ga _0.45 N active layer 604, (4) light guide layer 605 made of undoped GaN, (5) n-type Ga
_0.7 Al _0.3 N cladding layer 605 (Si-doped, p = 1
× 10 ¹⁸ cm ⁻³ , thickness: 20 nm), (6) n-type Ga
An N cap layer 606. The In _0.55 Ga _0.45 N active layer 604 is a light guide layer 60 made of undoped GaN.
The active layer sandwiched between 3 and 605 can be of either a constant composition such as a double heterostructure or a structure having a energetically modulated structure such as a multiple quantum structure. However, when a material having a constant composition is used, it must be formed so as to cause fluctuation of the periodic composition of In and Ga during crystal growth, that is, a so-called natural superlattice. In this example, In _0.55 Ga _0.45 N crystal-grown under the condition that a natural superlattice is formed was used as the active layer.

Next, mammanesium (Mg) is introduced into a part of the wafer thus prepared. First, silicon dioxide (SiO ₂ ) was formed on the prepared wafer by a usual thermochemical deposition method.
A film was deposited about 200 nm. The SiO ₂ film 110, the n-type GaN cap layer 606, and a part of the n-type AlGaN cladding layer 605 are removed using a photolithographic technique, leaving a stripe shape having a width of 5 μm to 10 μm.
Next, magnesium ions are implanted at an acceleration voltage of about 600 kV using the SiO ₂ film 607 and the n-type GaN cap layer 606 as a mask. Magnesium ions implanted at this accelerating voltage have a thickness of about 0.5 μm in the n-type AlGaN layer.
Penetrates and distributes to a position of about 0.3 μm from the active layer.
Such a wafer is placed in nitrogen at 1000 degrees Celsius to 11 degrees Celsius.
By heating to 00 degrees, the driving layer 6
Diffusion of magnesium was performed to reach 04.

In this structure, the n-type Ga _0.7 Al _0.3 N cladding layer 605 containing nitrogen as a main group V element has a high resistance by implanting magnesium, so that there is no need to provide an additional current confinement structure.

After removing the SiO ₂ film 111, an n-side electrode 113 made of an Au—Ge alloy is provided by an electron beam evaporation method in vacuum.
From the n-side electrode 113 to the active layer 604 over the width of about 10 μm at the center of the two stripes so that current can be independently injected into the two stripes provided with the p-type electrode 114 made of an Au—Zn alloy. The removed groove 610 was formed, and both stripes were electrically separated. FIG. 18 is a sectional view of the semiconductor laser device formed as described above. The figure is a cross-sectional view at a plane crossing the optical axis of the laser.

The wafer prepared in this way is about 250 μm long.
c to form a laser chip. The end face of the semiconductor laser device is covered with a multilayer reflective film having a reflectance of 64%. An example of this reflection film is composed of a multilayer film of a SiO2 film and an amorphous silicon film.

The above-described semiconductor laser chip was bonded to a Cu-made stem with its bonding surface facing upward, and electricity was supplied. The semiconductor laser device of this example has a wavelength of 410 nm and a threshold current of about 50.
It oscillates continuously at room temperature with mA, the maximum light output is about 300mW,
A continuous operation for 5000 hours or more was possible at an optical output of 100 mW.

[0120]

According to the present invention, the waveguide structure and the current confinement structure of the semiconductor optical device can be realized by a simple method. Therefore, according to the present invention, the output of the semiconductor laser device can be greatly improved without deteriorating characteristics other than the output.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an example of a semiconductor laser device according to the related art.

FIG. 2 is a diagram showing each element distribution, impurity concentration, and hole concentration in a compound semiconductor material according to the present invention.

FIG. 3 is a cross-sectional view of a wafer showing a state in which impurities are diffused into the semiconductor laminate according to the first embodiment.

FIG. 4 is a cross-sectional view of the semiconductor laser device according to the first embodiment of the present invention.

FIG. 5 is a cross-sectional view showing the arrangement of a plurality of light-emitting portions of a semiconductor laser device according to a second embodiment and the relationship with tracks.

FIG. 6 is an explanatory diagram showing a basic configuration of an optical disk device.

FIG. 7 is a cross-sectional view of a wafer showing a state where impurities are diffused into a semiconductor laminate according to a third embodiment.

FIG. 8 is a cross-sectional view of a semiconductor laser device according to a third embodiment of the present invention.

FIG. 9 is a wafer cross section showing a state in which impurities are diffused into a semiconductor laminate according to a fourth embodiment.

FIG. 10 is a plan view showing an arrangement of stripes according to a fourth embodiment.

FIG. 11 is a sectional view of a semiconductor laser device according to a fourth embodiment of the present invention.

FIG. 12 is a cross-sectional view of a wafer showing a state in which impurities are diffused into a semiconductor multilayer body according to a fifth embodiment.

FIG. 13 is a sectional view of a semiconductor laser device according to a fifth embodiment of the present invention.

FIG. 14 is a plan view showing an arrangement of stripes according to a sixth embodiment.

FIG. 15 is a wafer cross section showing a state in which impurities are diffused into a semiconductor laminate according to a sixth embodiment.

FIG. 16 is a sectional view of a semiconductor laser device according to a sixth embodiment of the present invention.

FIG. 17 is a wafer cross section showing a state in which impurities are diffused into a semiconductor laminate according to a seventh embodiment.

FIG. 18 is a sectional view of a semiconductor laser device according to a seventh embodiment of the present invention.

[Explanation of symbols]

1: substrate crystal, 2: first cladding layer, 3: light guide layer, 4: multiple quantum well structure region, 5: passivation film, 6: light guide layer, 7: second cladding layer, 8: cap Layer, 9: n-side electrode, 10: p-side electrode, 11: impurity diffusion region, 12: mixed crystal region, 21: disk, 2
2: motor, 23: optical pickup, 24: lens system,
25: semiconductor laser element, 26: photodetector, 27: control circuit, 101: p-type GaAs substrate, 102: p-type Al
GaAs cladding layer, 103: multiple quantum well active layer, 1
04: n-type AlGaAs first cladding layer, 105: n
AlGaInP second cladding layer, 106: n-type In
GaP layer, 107: n-type GaAs cap layer, 108:
AlGaAs well layer, 109: AlGaAs barrier layer, 110: SiO ₂ film, 111: ZnO film, 21
1: zinc diffusion region, 113: n-side electrode, 114: p-side electrode, 115: groove, 201: first p-type cladding layer of AlGaAs, 202: p-type InGaP layer, 203: Al
GaInP second p-type cladding layer, 301: n-type GaAs
s substrate, 302: n-type AlGaAs cladding layer, 30
3: p-type AlGaAs cladding layer, 304: p-type Ga
As cap layer, 305: SiO ₂ film, 306: p-type A
lGaInP current block layer, 401: p-type AlGa
InP clad layer, 402: AlGaInP light guide layer, 403: GaInP active layer, 404: n-type AlG
aInP cladding layer, 405: n-type GaInP layer, 5
01: n-type GaAs substrate, 502: n-type AlGaIn
P cladding layer, 503: GaInP active layer, 504:
p-type AlGaInP cladding layer, 201: substrate crystal, 2
02: first cladding layer, 203: active layer, 204: second cladding layer, 209: step, 210, 211, 2
12: Planar part, 213, 214, 215: Laser emitting part, 216, 217: Track, 218, 219, 22
0, 221: irradiation spot, 503: multiple quantum well active layer, 504: p- (Al _0.7 Ga _0.3 ) _0.5 In _0.5 P
Cladding layer 505: n-type GaAs cap layer, 506: GaIn
P well layer, 507: AlGaInP barrier layer, 508
: Extended wavelength shortening region, 509: Slit region, 51
0: stripe-shaped residual portion of ZnO film, 601: GaN
Substrate, 602: p-type cladding layer, 603: light guide layer,
604: active layer, 605: light guide layer, 606: n-type cladding layer, 607: cap layer, 608: silicon dioxide film, 609: impurity diffusion region, 610: trench, 611: n
Side electrode, 612: p-side electrode

 ──────────────────────────────────────────────────の Continuing on the front page (72) Kenichi Uejima Inventor, Semiconductor Company Headquarters, Hitachi, Ltd. 5-2-1, Kamizuhoncho, Kodaira City, Tokyo (72) Inventor Keiichi Miyauchi Kamimizuhoncho, Kodaira City, Tokyo 5-20-1, Hitachi Semiconductor Co., Ltd. Semiconductor Business Headquarters (72) Inventor Yoshiaki Kato 5-20-1, Kamisumihonmachi, Kodaira-shi, Tokyo F-term, Hitachi Semiconductor Co., Ltd. Semiconductor Business Headquarters 5F073 AA07 AA13 AB04 BA06 CA06 CA07 CA14 CB19 DA13 DA14 DA15

Claims (9)

[Claims] A first conductive type substrate crystal and a first conductive type semiconductor layer formed on the substrate crystal.
An active layer composed of a direct transition type semiconductor layer having a narrower band gap than the first cladding layer, and a second conductive type semiconductor layer having a wider band gap than the active layer. And a second clad layer constituted by the above, and light is guided to the stripe portion by introducing an impurity into at least a side portion of a stripe-shaped portion serving as an optical waveguide of the semiconductor laminate. Has a function, at least a part of the layered structure of the semiconductor laminate,
A semiconductor laser device comprising a compound semiconductor layer containing phosphorus and nitrogen. 2. The method according to claim 1, wherein the impurity is at least one of zinc and magnesium.
13. The semiconductor laser device according to claim 1. 3. The semiconductor laser device according to claim 1, wherein said compound semiconductor layer containing phosphorus and nitrogen is one selected from the group consisting of AlInP, GaInP, and AlGaInP. 4. The semiconductor laser device according to claim 1, wherein the compound semiconductor layer containing phosphorus and nitrogen is one selected from the group consisting of AlInN, GaInN, and AlGaInN. 5. The semiconductor device according to claim 1, wherein the first conductivity type is a p-type conductivity, and the second conductivity type is an n-type conductivity. The semiconductor laser device according to claim 1, wherein the semiconductor laser device is located on a side opposite to the side. 6. A semiconductor laminate having a plurality of semiconductor layers has a stripe-shaped portion serving as an optical waveguide, and a current is confined in the stripe portion by introducing an impurity into at least a side portion of the stripe-shaped portion. Wherein at least a part of the layered structure of the semiconductor laminate having the function of narrowing the current is formed of a compound semiconductor layer containing at least one of phosphorus and nitrogen. element. 7. The device according to claim 1, wherein a plurality of the stripe portions are provided substantially in parallel.
The semiconductor laser device according to any one of the above. 8. A semiconductor laminate having a plurality of semiconductor layers has a stripe-shaped portion serving as an optical waveguide, and light is guided to the stripe portion by introducing an impurity into at least a side portion of the stripe-shaped portion. At least part of the layered structure of the semiconductor laminate having a function of wave-guiding and having the function of guiding light is formed of a compound semiconductor layer containing at least one of phosphorus and nitrogen. Semiconductor optical device. 9. A semiconductor having a plurality of semiconductor layers configured to have a compound semiconductor layer containing at least one of phosphorus and nitrogen in at least a part of a layered semiconductor laminate having a function of guiding light. A step of forming a stacked body, wherein the semiconductor stacked body has a stripe-shaped portion serving as an optical waveguide, and an impurity reaches at least a side portion of the striped portion and reaches the compound semiconductor layer containing at least the phosphorus and nitrogen. A method of manufacturing a semiconductor laser device, comprising: