JP2006005000A - Semiconductor light emitting element, its manufacturing method, and optical module - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a semiconductor light emitting element capable of preventing the increase of a threshold current density and capable of elongating the life of element while being improved in reliability, and to provide its manufacturing method. <P>SOLUTION: An activated layer 16 having the multilayer quantum well structure of a well layer and a barrier layer is provided on a substrate 11 consisting of GaAs. The well layer is constituted of GaInNAs mixed crystal and the lattice inconsistency with respect to the substrate 11 of activated layer 16 is increased so as to be not less than 2%. The activated layer 16 contains carbon (C) as an impurity and the segregation of indium is suppressed in the well layer by the carbon as an impurity whereby the local variability of density in the well layer is suppressed even when the lattice inconsistency with respective to the substrate 11 of activated layer 16 is large. Accordingly, the density of states in the well layer is equalized whereby a gain and a current density are equalized. According to this method, the threshold current density is lowered and the life of element is elongated whereby reliability is improved. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a semiconductor light-emitting element suitable as a long-wavelength light-emitting element, a manufacturing method thereof, and an optical module using the semiconductor light-emitting element.

  Semiconductor light emitting devices that emit light with a long wavelength of 1.2 μm or more have various application fields such as optical communication systems and biosensing. In particular, a semiconductor light emitting device having an oscillation wavelength of 1.3 μm or 1.55 μm is mainly used for optical communication applications and will be the core of future communication technology. Various materials are currently used for the active layer of such a long-wavelength light emitting device for communication. Among them, GaInNAs mixed crystal is an active material that can be produced on a GaAs substrate that can be manufactured at a low cost and with a large diameter. In recent years, it has been regarded as promising as a layer material (for example, see Non-Patent Document 1).

In order to obtain light emission with an oscillation wavelength of 1.2 μm or more using a GaInNAs active layer on a GaAs substrate, it is necessary to increase the indium (In) composition or the nitrogen (N) composition. However, since nitrogen has a greatly different atomic radius than other constituent elements and has a different electronegativity, it is considered desirable to prevent the nitrogen composition from becoming too large. Therefore, it is necessary to increase the indium composition to some extent, for example, 20% or more.
K. Nakahara, 4 others, 1.3um continuous-wave lasing operation in GaInNAs quantum-well lasers, "Photonics Technology Letters", (USA), IEEE (The Institute of Electrical and Electronic Engineers, Inc.), April 1998, Vol. 10, No. 4, p. 487-488

  However, in the quantum well laser using the GaInNAs active layer on the GaAs substrate as described above, when the indium composition is increased, the lattice mismatch of the active layer with respect to the substrate increases to 2% or more, and depending on the growth conditions. Since indium tends to aggregate, indium concentration distribution (segregation) may occur in the well layer. This concentration distribution of indium leads to a distribution of density of states in the active layer, so that the gain is not uniform in the active layer, the threshold current density is increased, and the device life is shortened. Will arise.

  The present invention has been made in view of such a problem, and an object thereof is to prevent an increase in threshold current density and to increase the lifetime of the element, and to improve the reliability of the semiconductor light-emitting element, its manufacturing method, and optical To provide a module.

A first semiconductor light emitting device according to the present invention has an active layer having a lattice mismatch with respect to the substrate of 2% or more on the substrate, and the active layer contains carbon (C) as an impurity. It is. The concentration of carbon is preferably in the range of 5 × 10 ¹⁶ (cm ⁻³ ) to 2 × 10 ¹⁸ (cm ⁻³ ).

A second semiconductor light emitting device according to the present invention is provided with an active layer made of a GaInNAs mixed crystal on a substrate, and the active layer contains carbon (C) as an impurity. The concentration of carbon is preferably in the range of 5 × 10 ¹⁶ (cm ⁻³ ) to 2 × 10 ¹⁸ (cm ⁻³ ).

  A first method for manufacturing a semiconductor light emitting device according to the present invention is a method for manufacturing a semiconductor light emitting device having an active layer having a lattice mismatch with respect to the substrate of 2% or more on the substrate. Carbon (C) is added.

  A second method for manufacturing a semiconductor light emitting device according to the present invention is to manufacture a semiconductor light emitting device having an active layer made of a GaInNAs mixed crystal on a substrate, and adding carbon (C) as an impurity to the active layer It is what you want to do.

  The first optical module according to the present invention includes the first semiconductor light emitting element, and the second optical module according to the present invention includes the second semiconductor light emitting element.

  According to the first semiconductor light emitting device of the present invention or the method for manufacturing the same, carbon (C) is contained as an impurity in the active layer. Therefore, the lattice mismatching with respect to the substrate of the active layer is caused by the carbon as the impurity. Even if it becomes 2% or more, it can suppress that the density | concentration varies locally in the active layer. Therefore, it is possible to suppress the occurrence of the state density distribution in the active layer, obtain a uniform gain, and make the current density uniform. As a result, the threshold current density can be reduced, the device life can be extended, and the reliability can be improved. Especially, when the substrate is made of GaAs and the active layer is made of GaInNAs, the long wavelength light emitting device with improved reliability. Can be realized.

  According to the second semiconductor light emitting device of the present invention or the method for manufacturing the same, since the active layer made of GaInNAs mixed crystal contains carbon (C) as an impurity, the carbon as the impurity causes indium in the active layer. Segregation of (In) can be suppressed. Therefore, it is possible to suppress the occurrence of the state density distribution in the active layer, obtain a uniform gain, and make the current density uniform. Thereby, the threshold current density is lowered, the element lifetime is extended, and a highly reliable long wavelength light emitting element can be obtained.

  According to the first or second optical module of the present invention, since the first or second semiconductor light emitting device according to the present invention is provided, the reliability is improved.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

(Semiconductor laser)
FIG. 1 shows a cross-sectional configuration of a semiconductor laser according to an embodiment of the present invention. The semiconductor laser 10 is a long wavelength laser having an oscillation wavelength of 1.2 μm or more used for communication or the like. For example, on the front side of the substrate 11, a first cladding layer 12, a second cladding layer 13, and a third cladding layer 14. The first light guide layer 15, the active layer 16, the second light guide layer 17, the fourth cladding layer 18, the fifth cladding layer 19, the sixth cladding layer 20, and the contact layer 21 are laminated in this order from the substrate 11 side. It has a configuration. The fifth clad layer 19, the sixth clad layer 20, and the contact layer 21 are thin strip-shaped ridges, and insulating layers 22 made of silicon dioxide (SiO ₂ ) or the like are formed on both sides thereof. Yes.

  For example, the substrate 11 has a thickness in the stacking direction (hereinafter simply referred to as a thickness) of about 450 μm and is made of n-type GaAs to which an n-type impurity such as silicon (Si) or selenium (Se) is added.

The first cladding layer 12 has a sufficient thickness of, for example, 1 μm or more and is composed of an n-type Al _0.3 Ga _0.7 As mixed crystal to which an n-type impurity such as silicon (Si) or selenium (Se) is added. . The second cladding layer 13 has a thickness of, for example, about 100 nm and is made of n-type GaAs to which an n-type impurity such as silicon (Si) or selenium (Se) is added. The third cladding layer 14 has, for example, a thickness of about 200 nm and is composed of an n-type Al _0.47 Ga _0.53 As mixed crystal to which an n-type impurity such as silicon (Si) or selenium (Se) is added.

The first light guide layer 15 has, for example, a thickness of about 100 nm and is made of Al _x Ga _1-x As mixed crystal (0 ≦ x <1) that does not contain impurities, specifically, for example, GaAs.

FIG. 2A schematically shows the band structure of the active layer 16. The active layer 16 has, for example, a multi quantum well (MQW) structure of a well layer 16A and a barrier layer 16B, and the total thickness thereof is, for example, about 60 nm. The well layer 16A includes, for example, at least one of gallium (Ga) and indium (In) among group 3B elements, and at least one of nitrogen (N) and arsenic (As) among group 5B elements. In this embodiment, for example, a Ga _1-y1 In _y1 N _z1 As _1-z1 mixed crystal (0 <y1 ≦ 1, 0 <z1 ≦ 1) is used. It is configured. Barrier layer 16B, for _{example, Ga 1-y2 In y2 N} z2 As 1-z2 mixed crystal (y1> y2 or z1> z2,0 ≦ y2 <1,0 ≦ z2 <1), specifically, for example a GaAs It is configured.

In the present embodiment, the indium composition y1 in the Ga _{1 -y1} In _y1 N _z1 As _{1 -z1} mixed crystal (0 <y1 ≦ 1, 0 <z1 ≦ 1) constituting the well layer 16A is somewhat high (for example, y1 Therefore, the lattice mismatch between the well layer 16A of the active layer 16 and GaAs constituting the substrate 11 is increased to 2% or more. The lattice mismatch of the well layer 16A with respect to the substrate 11 is obtained by subtracting the lattice constant of the substrate 11 from the lattice constant of the well layer 16A, dividing the difference by the lattice constant of the substrate 11, and multiplying the obtained value by 100. It is calculated by.

  The well layer 16A and the barrier layer 16B of the active layer 16 contain carbon (C) as an impurity. As described above, when indium segregates in the well layer 16A of the active layer 16, the lattice mismatch of the well layer 16A with respect to the substrate 11 varies locally in the well layer 16A, which is indicated by a dotted line in FIG. As described above, the state density fluctuates in the well layer 16A, and as a result, the threshold current density increases and the device lifetime decreases. In the present embodiment, carbon is added as an impurity to the active layer 16 to suppress the segregation of indium, and the fluctuation of the state density is suppressed as shown by the solid line in FIG. By making the density uniform, the threshold current density is lowered, the device life is extended, and the reliability is increased.

The concentration of carbon as an impurity is preferably 5 × 10 ¹⁶ (cm ⁻³ ) or more and 2 × 10 ¹⁸ (cm ⁻³ ) or less, for example. This is because if it is lower than 5 × 10 ¹⁶ (cm ⁻³ ), it is difficult to sufficiently suppress the variation in lattice mismatch in the well layer 16A. Further, if it is larger than 2 × 10 ¹⁸ (cm ⁻³ ), the carbon content is too high, and the disorder of crystallinity may increase. Further, since the position of the pn junction is separated from the position of the active layer 16, efficient carrier injection may be hindered, so that the threshold current amount necessary for stimulated emission may increase. It is. Furthermore, it is more preferable that the concentration of carbon as an impurity is, for example, 1 × 10 ¹⁷ (cm ⁻³ ) or more and 1 × 10 ¹⁸ (cm ⁻³ ) or less.

Carbon is conventionally used as a p-type impurity in the active layer for the purpose of improving high-frequency characteristics. However, in the case of an active layer made of a GaInNAs mixed crystal, carbon is not included as a p-type impurity. Neither is it disclosed, nor is a document containing such a description disclosed by the inventor. Rather, in general, when GaInNAs mixed crystals are formed, the MOCVD (Metal Organic Chemical Vapor Deposition) method does not prevent carbon contamination from the methyl group (CH ₃ ). The MBE (Molecular Beam Epitaxy) method that can be grown in a carbon-free system is widely adopted. Further, in the present embodiment, the lattice mismatch of the active layer 16 with respect to the substrate 11 is extremely large as 2% or more. However, the material system in which the lattice mismatch is increased is very limited. Even in the case of an InGaAs mixed crystal generally considered to have a large lattice mismatch, for example, for YAG excitation, the indium composition is about 10% and the lattice mismatch is about 0.712%. In the case of ZnCdSe, the lattice mismatch does not reach 2%. In addition, lattice mismatch such as AlGaAs mixed crystal, GaInP mixed crystal, or AlGaInP mixed crystal is less than 1%, and there is almost no lattice distortion.

  The well layer 16A preferably does not substantially contain aluminum (Al). This is because if the well layer 16A made of GaInNAs mixed crystal contains aluminum, there is a risk of deterioration.

The second light guide layer 17 has, for example, a thickness of about 100 nm and is made of Al _x Ga _1-x As mixed crystal (0 ≦ x <1) that does not contain impurities, specifically, for example, GaAs.

For example, the fourth cladding layer 18 has a thickness of about 200 nm and is made of a p-type Al _0.47 Ga _0.53 As mixed crystal to which a p-type impurity such as zinc (Zn) is added. For example, the fifth cladding layer 19 has a thickness of about 100 nm and is made of p-type GaAs to which a p-type impurity such as zinc (Zn) is added. The sixth cladding layer 20 has a sufficient thickness of, for example, 1 μm or more and is made of a p-type Al _0.3 Ga _0.7 As mixed crystal to which a p-type impurity such as zinc (Zn) is added.

  The first cladding layer 12 and the sixth cladding layer 20 have the same refractive index n1, the second cladding layer 13 and the fifth cladding layer 19 have the same refractive index n2, and the third cladding layer 14 and the fourth cladding layer 19 The clad layer 18 has the same refractive index n3. The refractive indexes n1, n2, and n3 preferably satisfy the relationship of n1, n3 <n2.

  The contact layer 21 is for forming an ohmic junction with a p-side electrode to be described later. For example, the contact layer 21 has a thickness of about 100 nm and is made of p-type GaAs to which a p-type impurity such as zinc (Zn) is added at a high concentration. It is configured.

  The semiconductor laser 10 has an n-side electrode 31 on the back side of the substrate 11. The n-side electrode 31 has a structure in which, for example, a gold (Au) layer, an alloy layer of gold (Au) and germanium (Ge), and a gold (Au) layer are sequentially laminated from the substrate 11 side and alloyed by heat treatment. And is electrically connected to the first cladding layer 12 through the substrate 11. On the other hand, a p-side electrode 32 is provided on the contact layer 21. The p-side electrode 32 has, for example, a structure in which a titanium (Ti) layer, a platinum (Pt) layer, and a gold (Au) layer are sequentially laminated from the contact layer 21 side and alloyed by heat treatment. 21 is electrically connected.

  In the semiconductor laser 10, for example, a pair of side surfaces opposed in the length direction of the contact layer 21 are resonator end surfaces, and a pair of reflecting mirror films (not shown) are formed on the pair of resonator end surfaces, respectively. Yes. Of the pair of reflecting mirror films, the reflectance of one reflecting mirror film is adjusted to be low, and the reflectance of the other reflecting mirror film is adjusted to be high. Thereby, the light generated in the active layer 16 is amplified by reciprocating between the pair of reflecting mirror films, and is emitted as a laser beam from one of the reflecting mirror films.

  This semiconductor laser 10 can be manufactured, for example, as follows.

  First, for example, the first clad layer 12, the first guide layer 13, the third clad layer 14 and the first clad layer made of the above-described thickness and material are formed on the front side of the substrate 11 made of the above-described thickness and material, for example, by MOCVD. The light guide layer 15 is laminated in order.

Next, the active layer 16 having the multiple quantum well structure of the well layer 16A and the barrier layer 16B is formed on the first light guide layer 15 by the MOCVD method. At this time, carbon (C) is added as an impurity to the well layer 16 </ b> A of the active layer 16. As the method, for example, there is a method of using auto-doping by a methyl group (CH ₃ ) generated along with decomposition of an organic metal raw material in the course of crystal growth by MOCVD. In that case, the concentration of carbon contained in the well layer 16A can be changed by increasing the growth temperature or adjusting the V / III ratio. Alternatively, carbon may be intentionally added by supplying carbon tetrabromide (CBr ₄ ) or carbon tetrachloride (CCl ₄ ) into the furnace of the MOCVD apparatus. In particular, CBr ₄ is preferable because it is less likely to damage the piping than CCl ₄ . Moreover, you may use these methods together.

  Subsequently, the second optical guide layer 17, the fourth cladding layer 18, the fifth cladding layer 19, the sixth cladding layer 20, and the contact layer made of the above-described thicknesses and materials are formed on the active layer 16 by the same MOCVD method. 21 are laminated in order.

  After that, a part of the fifth cladding layer 19, the sixth cladding layer 20, and the contact layer 21 is selectively removed by etching, for example, to form a thin strip-shaped protrusion (ridge). After the fifth clad layer 19, the sixth clad layer 20 and the contact layer 21 are formed into thin strip-shaped ridges, both sides thereof are made of the above-described material by, for example, a CVD (Chemical Vapor Deposition) method. An insulating layer 22 is formed.

  After forming the insulating layer 22, for example, the back side of the substrate 11 is ground to a thickness of the substrate 11 of about 100 μm, and the n-side electrode 31 is formed on the back side of the substrate 11. Further, an opening is provided in the insulating layer 22 corresponding to the contact layer 21 by, for example, etching, and the p-side electrode 32 is formed on the contact layer 21 and the insulating layer 22. After the n-side electrode 31 and the p-side electrode 32 are formed, the substrate 11 is adjusted to a predetermined size, and a reflecting mirror film (not shown) is formed on a pair of resonator end faces facing in the length direction of the contact layer 21. Thereby, the semiconductor laser 10 shown in FIG. 1 is formed.

  In the semiconductor laser 10, when a predetermined voltage is applied between the n-side electrode 31 and the p-side electrode 32, the current confined by the contact layer 21, the sixth cladding layer 20, and the fifth cladding layer 19 The light is injected into the active layer 16 to emit light by electron-hole recombination. Here, since the active layer 16 contains carbon as an impurity, segregation of indium is suppressed in the well layer 16A, and even if the lattice mismatch of the active layer 16 with respect to the substrate 11 increases to 2% or more, the well Local variations in indium concentration in the layer 16A are suppressed. Therefore, the state density in the well layer 16A is made uniform, and the gain and the current density are made uniform. Thereby, the threshold current density is lowered, the device life is extended, and the reliability is improved.

(Optical module)
FIG. 3 schematically shows the configuration of an optical module including such a semiconductor laser 10. The optical module 100 is used as an FEM (front end module) that converts an optical signal and an electric signal in a high-speed optical communication system, and includes a transmission unit 110 and a reception unit 120 on a base 101. Yes. Fibers 130 and 140 are connected to the transmission unit 110 and the reception unit 120 via connectors (not shown), respectively.

  The transmission unit 110 includes, for example, the semiconductor laser 10 described above and a driver 112 that drives the semiconductor laser 10. As the driver 112, a known driver IC (Integrated Circuit) can be used.

  The receiving unit 120 is a general unit including, for example, a photoelectric conversion element (photodiode) 121 and an amplifier 122 such as a TIA (transimpedance amplifier) or LIA (limiting impedance amplifier).

  In the optical module 100, in the transmission unit 110, the semiconductor laser 10 is driven by the driver 112 based on the electric signal S1 supplied from the outside, and the optical signal P1 is transmitted through the fiber 130. In the receiving unit 120, the optical signal P2 supplied via the fiber 140 is incident on the photoelectric conversion element 121 and converted into an electric signal. The electric signal is amplified by the amplifier 122, and necessary conversion processing is applied. And output to the outside as an electrical signal S2. Here, since the optical module 100 includes the semiconductor laser 10 according to the present embodiment, by transmitting a signal by transmitting and receiving light, high-speed transmission of Gbps (gigabit per second) or more is possible, and the semiconductor laser 10 Therefore, the reliability of the optical module 100 is also improved.

  As described above, in the semiconductor laser 10 of the present embodiment, since carbon is added as an impurity to the active layer 16, it is possible to suppress indium from segregating in the well layer 16A due to the carbon as the impurity. Even if the lattice mismatch between the 16 well layers 16A and the substrate 11 is as large as 2% or more, it is possible to suppress the local concentration variation in the well layer 16A. Therefore, it is possible to suppress the occurrence of the state density distribution in the well layer 16A, obtain a uniform gain, and make the current density uniform. As a result, the threshold current density is reduced, the device life is extended, and the reliability is improved. Therefore, also in the optical module 100 using this semiconductor laser 10, the reliability is improved.

  In the present embodiment, the case where the well layer 16A and the barrier layer 16B of the active layer 16 contain carbon as an impurity has been described. However, at least one of the well layer 16A and the barrier layer 16B contains carbon as an impurity. It should just contain. For example, even if only the barrier layer 16B contains carbon as an impurity, the above-described effects can be obtained by diffusion or the like. It is more preferable that both the well layer 16A and the barrier layer 16B contain carbon as an impurity, and it is most preferred that only the well layer 16A contains carbon as an impurity. This is because a higher effect can be obtained.

  In the present embodiment, the case where the well layer 16A of the active layer 16 of the semiconductor laser 10 is made of GaInNAs mixed crystal has been described. However, the well layer 16A is made of a material other than the GaInNAs mixed crystal. May be. Other constituent materials of the well layer 16A include, for example, a GaInNAsSb mixed crystal, a GaNAs mixed crystal, or a GaNAsSb mixed crystal.

  Furthermore, specific examples of the present invention will be described.

(Examples 1-6)
The semiconductor laser 10 shown in FIG. 1 was fabricated in the same manner as in the above embodiment. At that time, carbon was added as an impurity to the well layer A and the barrier layer 16B of the active layer 16 by supplying CBr ₄ as a carbon source in the growth process of the well layer 16A and the barrier layer 16B of the active layer 16. The concentration of carbon is 2.5 × 10 ¹⁶ (cm ⁻³ ) in Example 1, 6.0 × 10 ¹⁶ (cm ⁻³ ) in Example 2, and Example ³ by controlling the flow rate of CBr _4. 1.3 × 10 ¹⁷ (cm ⁻³ ) in Example 4, 3.0 × 10 ¹⁷ (cm ⁻³ ) in Example 4, 8.5 × 10 ¹⁷ (cm ⁻³ ) in Example 5, and 1 in Example 6 .6 × 10 ¹⁸ (cm ⁻³ ). In addition, the carbon concentration in each of Examples 1 to 6 was measured by a SIMS (Secondary Ion Mass Spectrometry) method.

  An aging test was performed on the obtained semiconductor lasers 10 of Examples 1 to 6. Among them, the results of Examples 1, 2, 4, and 6 are shown in FIG. FIG. 5 shows the relationship between the carbon concentration and the lifetime of the semiconductor lasers 10 of Examples 1 to 6.

As can be seen from FIG. 4, in Examples 1, 2, and 4, the higher the concentration of carbon, the lower the operating current amount. In Example 4, the operating current amount is 30 mA or less and the lifetime is about 10 ³ h or more, which is extremely good. Results were obtained. However, in Example 6 in which the carbon concentration was higher than in Example 4, only a value substantially equivalent to that in Example 2 was obtained. Further, as can be seen from FIG. 5, the device lifetime becomes longer as the carbon concentration is increased, and after reaching the maximum value in the vicinity of 3.0 × 10 ¹⁷ (cm ⁻³ ) corresponding to Example 4, it tends to become shorter again. Was seen. When the carbon concentration is in the range of 5 × 10 ¹⁶ (cm ⁻³ ) or more and 2 × 10 ¹⁸ (cm ⁻³ ) or less, a long life of about 10 ² h or more is obtained, and further, 1 × 10 ¹⁷ (cm ⁻³ ). In the range of 1 × 10 ¹⁸ (cm ⁻³ ) or less, the length could be made longer than about 6 × 10 ² h.

  By optimizing the concentration of carbon as an impurity as described above, the amount of operating current and the lifetime can be improved because segregation of indium is suppressed in the well layer 16A and the lattice defect of the well layer 16A with respect to the substrate 11 is suppressed. It is presumed that even if the consistency is large, the concentration variation in the well layer 16A can be suppressed. Thus, it is considered that a uniform gain can be obtained by suppressing the distribution of the state density in the well layer 16A, and the current density can be made uniform. The reason why the segregation of indium is suppressed by carbon as an impurity is that lattice hardening, that is, the addition of carbon hardens the crystal lattice and makes dislocations difficult to grow, or the surfactant effect, that is, the indium It is conceivable that aggregation is prevented and the crystallinity of the active layer 16 is improved.

That is, if the concentration of carbon as an impurity is within an optimal range of 5 × 10 ¹⁶ (cm ⁻³ ) to 2 × 10 ¹⁸ (cm ⁻³ ), the amount of operating current can be reduced, and the element It was found that the lifetime can be extended and the reliability can be further improved.

  The present invention has been described with reference to the embodiments and examples. However, the present invention is not limited to the above embodiments and examples, and various modifications can be made. For example, the material and thickness of each layer described in the above embodiments and examples, or the film formation method and film formation conditions are not limited, and other materials and thicknesses may be used, or other film formation methods. Alternatively, film forming conditions may be used.

  For example, in the above-described embodiments and examples, the case where the first cladding layer 12 or the contact layer 21 is formed by the MOCVD method has been described, but a vacuum growth method such as the MBE method may be used. When the MBE method is used in this way, as a method for adding carbon as an impurity to the active layer 16, for example, carbon disposed in the K-cell may be heated.

  In the above-described embodiments and examples, the configuration of the semiconductor laser is specifically described. However, it is not necessary to provide all layers, and other layers may be further provided.

  Further, in the above-described embodiments and examples, the first cladding layer 12 having the n-type conductivity to the first light guide layer 15, the active layer 16, and the first having the p-type conductivity are formed on the n-type substrate 11. Although the case where the two light guide layers 17 to the contact layer 21 are laminated in order from the substrate 11 side has been described, the first cladding layer to the first light guide having p-type conductivity on the p-type or insulating substrate. A layer, an active layer, and a second light guide layer or contact layer having p-type conductivity may be stacked in order from the substrate side.

  In addition, although the case of the edge emitting semiconductor laser has been described in the above embodiments and examples, the present invention does not depend on the laser form and can be applied to, for example, a surface emitting laser.

  Furthermore, in the above-described embodiments and examples, the semiconductor laser has been described as an example. However, in addition to the semiconductor laser, the present invention is not limited to the light receiving element, HEMT (High Electron Mobility Transistor), FET (Field The present invention can also be applied to other semiconductor elements such as Effect Transisitor (field effect transistor).

  The semiconductor light emitting device and the manufacturing method thereof according to the present invention are suitable for, for example, a communication laser used as a light source for optical fiber communication or optical wiring and the manufacture thereof. The optical module according to the present invention can be used in a system for transferring image information in a baseband or a system such as a LAN (Local Area Network) / SAN (Storage Area Network).

It is sectional drawing showing the structure of the semiconductor laser which concerns on one embodiment of this invention. It is a figure which represents roughly the band structure of the active layer shown in FIG. It is a figure which represents typically the structure of the optical module provided with the semiconductor laser shown in FIG. It is a characteristic view showing the result of the Example of this invention. It is a characteristic view showing the result of the Example of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 11 ... Board | substrate, 12 ... 1st clad layer, 13 ... 2nd clad layer, 14 ... 3rd clad layer, 15 ... 1st light guide layer, 16 ... Active layer, 16A ... Well layer, 16B ... Barrier layer, 17 ... 2nd light guide layer, 18 ... 4th cladding layer, 19 ... 5th cladding layer, 20 ... 6th cladding layer, 21 ... contact layer, 22 ... insulating layer, 31 ... p-side electrode, 32 ... n-side electrode

Claims (36)

A semiconductor light emitting device comprising an active layer having a lattice mismatch with respect to the substrate of 2% or more on the substrate,
The active layer contains carbon (C) as an impurity. The active layer has a multiple quantum well structure including a well layer and a barrier layer, the lattice mismatch of the well layer with respect to the substrate is 2% or more, and at least one of the well layer and the barrier layer Carbon (C) is contained in one side, The semiconductor light-emitting device of Claim 1 characterized by the above-mentioned. The semiconductor light emitting element according to claim 1, wherein the oscillation wavelength is 1.2 μm or more. 2. The semiconductor light emitting element according to claim 1, wherein the concentration of carbon as the impurity is 5 × 10 ¹⁶ (cm ⁻³ ) or more and 2 × 10 ¹⁸ (cm ⁻³ ) or less. The well layer includes at least one of gallium (Ga) and indium (In) among group 3B elements and at least one of nitrogen (N) and arsenic (As) among group 5B elements. The semiconductor light-emitting device according to claim 2, comprising a compound semiconductor. The semiconductor light emitting element according to claim 5, wherein the well layer is made of a GaInNAs mixed crystal. The semiconductor light emitting element according to claim 1, wherein the substrate is made of gallium arsenide (GaAs). A semiconductor light emitting device comprising an active layer made of a GaInNAs mixed crystal on a substrate,
The active layer contains carbon (C) as an impurity. The active layer has a multiple quantum well structure including a well layer and a barrier layer, and carbon (C) is contained in at least one of the well layer and the barrier layer. Semiconductor light emitting device. The concentration of carbon as the impurity is 5 × 10 ¹⁶ (cm ⁻³ ) or more and 2 × 10 ¹⁸ (cm ⁻³ ) or less. The semiconductor light-emitting element according to claim 8. The semiconductor light emitting element according to claim 9, wherein the well layer is made of a GaInNAs mixed crystal. The semiconductor light emitting element according to claim 8, wherein the substrate is made of gallium arsenide (GaAs). A method of manufacturing a semiconductor light emitting device comprising an active layer having a lattice mismatch with respect to the substrate of 2% or more on the substrate,
Carbon (C) is added as an impurity to the active layer. A method for manufacturing a semiconductor light emitting device. The active layer has a multiple quantum well structure including a well layer and a barrier layer, the lattice mismatch of the well layer to the substrate is 2% or more, and at least one of the well layer and the barrier layer Carbon (C) is added. The manufacturing method of the semiconductor light-emitting device according to claim 13. The method for manufacturing a semiconductor light-emitting element according to claim 13, wherein the oscillation wavelength is 1.2 μm or more. The method of manufacturing a semiconductor light emitting element according to claim 13, wherein a concentration of carbon as the impurity is 5 × 10 ¹⁶ (cm ⁻³ ) or more and 2 × 10 ¹⁸ (cm ⁻³ ) or less. The well layer includes at least one of gallium (Ga) and indium (In) among group 3B elements and at least one of nitrogen (N) and arsenic (As) among group 5B elements. It comprises a compound semiconductor. The manufacturing method of the semiconductor light-emitting device of Claim 14 characterized by the above-mentioned. The method of manufacturing a semiconductor light emitting element according to claim 17, wherein the well layer is made of a GaInNAs mixed crystal. The method for manufacturing a semiconductor light-emitting element according to claim 13, wherein the substrate is made of gallium arsenide (GaAs). A method for manufacturing a semiconductor light emitting device comprising an active layer made of GaInNAs on a substrate,
Carbon (C) is added as an impurity to the active layer. A method for manufacturing a semiconductor light emitting device. 21. The semiconductor light emitting device according to claim 20, wherein the active layer has a multiple quantum well structure including a well layer and a barrier layer, and carbon (C) is added to at least one of the well layer and the barrier layer. Device manufacturing method. 21. The method of manufacturing a semiconductor light emitting element according to claim 20, wherein the concentration of carbon as the impurity is 5 × 10 ¹⁶ (cm ⁻³ ) or more and 2 × 10 ¹⁸ (cm ⁻³ ) or less. The method for manufacturing a semiconductor light emitting element according to claim 21, wherein the well layer is made of a GaInNAs mixed crystal. The method for manufacturing a semiconductor light emitting element according to claim 20, wherein the substrate is made of gallium arsenide (GaAs). An optical module comprising a semiconductor light emitting element on a substrate,
The semiconductor light-emitting element has an active layer having a lattice mismatch with respect to the substrate of 2% or more, and contains carbon (C) as an impurity in the active layer. The active layer has a multiple quantum well structure including a well layer and a barrier layer, the lattice mismatch of the well layer with respect to the substrate is 2% or more, and at least one of the well layer and the barrier layer 26. The optical module according to claim 25, wherein one side contains carbon (C). The optical module according to claim 25, wherein an oscillation wavelength of the semiconductor light emitting element is 1.2 µm or more. 26. The optical module according to claim 25, wherein the concentration of carbon as the impurity is 5 × 10 ¹⁶ (cm ⁻³ ) or more and 2 × 10 ¹⁸ (cm ⁻³ ) or less. The well layer includes at least one of gallium (Ga) and indium (In) among group 3B elements and at least one of nitrogen (N) and arsenic (As) among group 5B elements. 27. The optical module according to claim 26, comprising a compound semiconductor. 30. The optical module according to claim 29, wherein the well layer is made of a GaInNAs mixed crystal. The optical module according to claim 25, wherein the substrate is made of gallium arsenide (GaAs). An optical module comprising a semiconductor light emitting element on a substrate,
The semiconductor light emitting element has an active layer made of GaInNAs on a substrate, and contains carbon (C) as an impurity in the active layer. The active layer has a multiple quantum well structure including a well layer and a barrier layer, and contains carbon (C) in at least one of the well layer and the barrier layer. Optical module. The optical module according to claim 32, wherein the concentration of carbon as the impurity is 5 × 10 ¹⁶ (cm ⁻³ ) or more and 2 × 10 ¹⁸ (cm ⁻³ ) or less. The optical module according to claim 33, wherein the well layer is made of a GaInNAs mixed crystal. The optical module according to claim 32, wherein the substrate is made of gallium arsenide (GaAs).

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