JPH01204487A - Semiconductor laser - Google Patents

Abstract

PURPOSE:To enhance the performance and reliability of a head for an optical disk by forming first and second double hetero structure semiconductor lasers on the same substrate. CONSTITUTION:First and second double hetero structure semiconductor lasers are formed on the same GaAs substrate 101, the first double hetero structure semiconductor laser is formed of Ga0.5In0.5P, or (AlxGa1-x)0.5In0.5P (0<x<1) as an active layer 104 and of (AlyGa1-y)0.5In0.5P (0<=x<=y<=1), or Al0.5In0.5P as clad layers 103, 105. The second double hetero structure semiconductor laser is preferably formed of Alx'Ga1-x'As (0<x'<1) as an active layer 110, and Aly' Ga1-y'As (0<x'<y'<1), (Aly''Ga1-y'')0.5P (0<y''<=1), or Al0.5In0.5P as a clad layer 109. Thus, the performance and reliability of the lasers when mounted on a head are enhanced.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a semiconductor laser device, and particularly to a two-wavelength integrated half-door laser device.

[Prior art and problems to be solved by the invention] A short wavelength semiconductor laser device with a wavelength of 0.78 μm and a wavelength of 0.58 to 0.6 are used as a light source for optical information processing of optical discs etc.
8 μm visible semiconductor laser devices are gaining in importance.

As a light source for optical discs, a dual semiconductor laser device that can record signals and simultaneously detect signals independently with one head is attracting attention. A conventional example of a dual semiconductor laser device is shown in FIG. This dual semiconductor laser device is an n-type G
On the aAs substrate 201, n-type A lo, 49
G ao, s+ A 5 layers 202. n-type A1...
, Ga, 0. , As guide layer 203. Undoped Ajr
, , Ga, , As layer 204 . p-type An@, 5G
ao, sAs layer 205. p-type A 1 o, ssG a
o, bzA s layer 206゜n-type GaAsjg2Q7
, Zn diffusion regions 208 are sequentially formed, and then the space between the two laser devices is removed by etching to form a semiconductor laser device in which two semiconductor lasers are integrated.

An integrated semiconductor laser device that has two light emitting parts and can drive each independently is described in the Japan Society of Applied Physics Preliminary Lectures (28p-Z H-6, partll).

p, 714. (1987, Spring)).

However, when recording on an optical disk and detecting it at the same time using a dual semiconductor laser device in which the two lasers have the same oscillation wavelength, noise is likely to be introduced during recording or detection, making it difficult to improve the performance and reliability of the optical disk head. The disadvantage was that it was not possible to convert.

SUMMARY OF THE INVENTION An object of the present invention is to provide a semiconductor laser device that eliminates such conventional drawbacks and can improve the performance and reliability of an optical disk head.

[Means to solve the problem]

The semiconductor laser device of the present invention is characterized in that a first double heterostructure semiconductor laser device and a second double heterostructure semiconductor laser device, which have different oscillation wavelengths, are formed on the same substrate.

Further, according to the present invention, the substrate is a GaAs substrate, and the first double heterostructure semiconductor laser device is made of GaAs.
a o, 51 n0.5P or (A J xG a
I-X)@, 5In0.5P (0<x<1) is used as the active layer, and (Aff.

Ga+-y) o, sl n0.5P (0≦x<y≦1
) or Aj2. ,,In0.5P as a cladding layer, the second double heterostructure semiconductor laser device is made of A
lX-Ga,-,'As (Q<x'<1) is the active layer, Aj2y+Ga+-y, As (0<x'<y
'<1) or (Aj!,,Ga,-,,)o,5ln
0.5P (0<y″≦1) or Aj'6.5Ino
It is preferable to use zsP as the cladding layer.

[For production]

As mentioned in the section on the prior art and problems to be solved by the invention, if the oscillation wavelengths of the dual semiconductor laser devices that integrate two lasers are equal to each other, it is possible to simultaneously record and detect on an optical disk using one head. Recording or detection errors are likely to occur when performed independently. For example, in the dual semiconductor laser device shown in Figure 2, the two light emitting parts are separated by about 100 μm, but the two laser beams cannot be distinguished on the head side, and the laser beam for recording is reflected or scattered. This is because the laser light enters the detection section within the same head and is introduced as noise, and the laser light for detection enters the recording section within the same head.

In order to distinguish the two laser beams on the head side, the oscillation wavelengths of the two lasers are selected to be different from each other, and a filter for selecting the wavelength is installed in the head, that is, one of the two laser beams is targeted. It can be seen that it is sufficient to allow only the laser beam with the wavelength of 2 to pass through, and not to allow the other laser beam to pass through.

Therefore, on the same n-type GaAs substrate,
G a o, s I n0.5P or (A It ,
A semiconductor laser having an active layer of Ga t-x)o, 5In0.5P (0<x<1) and Alx-Ga, -x'A
By integrating a semiconductor laser with s (0 <x'< 1) as its active layer, it achieves higher performance and reliability when mounted on a head without compromising the functionality of conventional dual semiconductor laser devices. can be converted into

〔Example〕

The present invention will be explained in detail below.

Figure 1 shows an undoped Qao, 51n0.5P layer as the active layer of one laser, and another layer of n0.5P on an n-type GaAs substrate.
Undoped Al1o, oqcao in the active layer of two lasers
An embodiment in which the present invention is applied to a dual wavelength, dual semiconductor laser device using , 9+AS will be described.

The structure of this semiconductor laser device will be explained based on its manufacturing method.

First, by MOVPE method, a Se-doped GaAs buffer layer 102 with a thickness of 1 μm and Se
Doped CAlo, aGao, b) o, sl n0.5P
The cladding layer 103 is 1pmSGao, sI n0.5P
The active layer 104 is 1 μm thick and Zn-doped (A 1 o, aG
a o, h) o, 5In0. lcrm the sp layer 105
After growing and forming the double heterostructure for the first semiconductor laser, the double heterostructure is chemically etched away in stripes to form the second semiconductor laser.

Then, the double heterostructure for the second semiconductor laser is Se-doped A j! o, sGa 6.5A
The S cladding layer 109 is 1 μm thick and undoped A j2 o
, oqGa o, qIAs activity 1110 to 0.1
/' ms Z n-doped Al! O,5Gao,sAs
A cladding layer 111 is sequentially grown to a thickness of 1 μm.

At this time, selective growth is performed and no crystal growth is performed on the double heterostructure for the first semiconductor laser.

Thereafter, a Zn-doped GaAs layer 108. Se-doped Ga
In order to narrow the current, the As layer 107 is formed so that the two light emitting parts are separated by about 100 μm, the p electrodes 112 are provided independently in the two lasers, and the n electrodes 113 are formed.

According to this embodiment, a dual semiconductor laser device having two wavelengths having oscillation wavelengths of 0.78 μm and 0.68 μm can be fabricated on the same substrate.

Although one embodiment of the present invention has been described above, the present invention is not limited to the composition of this embodiment, and it goes without saying that other compositions can also be applied.

〔Effect of the invention〕

As described above, according to the present invention, the oscillation wavelengths of two lasers can be changed without impairing all the functions of conventional dual semiconductor lasers.

Thereby, performance for simultaneous recording and detection on the same head can be improved and reliability can be improved.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a semiconductor laser device according to an embodiment of the present invention, and FIG. 2 is a sectional view of a conventional semiconductor laser device. 101.201 ・n-GaAs substrate 102
... n-GaAs buffer layer 103 ... n
(Aj!o1Gao, 6) o, sI n0.5P cladding layer 104 ... Gao, sI no, s P active layer 105 ・'' p(AIo, 4G30.6) 0.5
1 n0.5P cladding layer 107...n-GaAs layer 108...p-GaAs layer 109...n Alo, s Gao, 5 As cladding layer 110...n Aj2o, owGao, glA
S active layer 111 ・ ・ ・ p AI! o,s
Gao,s AsJ! 112...p electrode 113...n electrode 202...n Alo, noGao, 31A3 layer 203...n-A lo,, lsG ao, 63A
3rd layer 204 --- Undoped Aj! o, o9Gao
, +nAS layer 205...pAn! o, 5 Gao, sAs layer 206
... p Aj! o, 5eGao, 62As layer 20
7-...n-GaAs layer 208...Zn diffusion region agent Patent attorney Yoshiyuki Iwasa

Claims (2)

[Claims] (1) A dual-wavelength integrated semiconductor, characterized in that a first double-hetero structure semiconductor laser device and a second double-hetero structure semiconductor laser device, which have different oscillation wavelengths, are formed on the same substrate. laser equipment. (2) The substrate is a GaAs substrate, and the first double heterostructure semiconductor laser device is made of GaAs.
＿0＿． _5In_0_. _5P or (Al_xGa
_1_-_x)_0_. _5In_0_. _5P(0<
x<1) as the active layer, (Al_yGa_1_-_y)
＿0＿． _5In_0_. _5P (0≦x<y≦1) or Al_0_. _5In_0_. _5P is used as a cladding layer, and the second double heterostructure semiconductor laser device is made of Al_x'Ga_1_-_x'As (0<x'<1)
is the active layer, Al_y'Ga_1_-_y'As(0
<x'<y'<1) or (Al_y"Ga_1_-_
y”)_0_._5In_0_._5P(0<y”≦1
) or Al_0_. _5In_0_. 2. The two-wavelength integrated semiconductor laser device according to claim 1, wherein the cladding layer is made of _5P.