JPS59175181A - Semiconductor laser device and manufacture thereof - Google Patents

Abstract

PURPOSE:To decrease the threshold current value by enhancing the effect of transverse mode and that of current striction by a method wherein the light absorption layer and the current striction layer of the titled device are successively provided independently. CONSTITUTION:A clad layer 12 is formed on an N type GaAs substrate 11. Next, an active layer 13 is formed, and then a clad layer 14 which shows the reverse conductivity is formed. The current striction layer 16 which shows the same conductivity as the layer 14 is formed. A stripe groove 5 is formed by etching from the layer 16 to a part of the layer 14. The sixth semiconductor layer 17 is formed on the groove 5 and the layer 16. A P type semiconductor layer 18 is formed, and a P-side electrode 19 and an N-side electrode 20 are formed on the layer 18 and the substrate 11. Here, the active layer can be also composed of the superlattice consisting of the super thin film of two or more kind of substances.

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to a semiconductor laser device particularly suitable for manufacturing a transverse mode controlled semiconductor laser device by metal organic vapor phase epitaxy, and its manufacture. Regarding the method.

It is something to do.

[Background of the invention]

A typical transverse mode semiconductor laser device manufactured by conventional metal organic vapor phase epitaxy (MOOVD method).

The control structure was as shown in Figure 1. (J.

,T,C! o71eman et aA, APL,
37 267 (1,980)) In Fig. 1, an n-type GaAs substrate 1, an n-type Ga1-xAs layer 2, a flat GaAs active layer 3, and a double-layered 10-telestructure structure formed in sequence are shown. It becomes a light absorption and current confinement layer.

The n-type GaAs layer 4 is replaced by the p-type GaAs layer 4, leaving a stripe region 5.
a, -x formed in the A7IxAs layer 6 and above p
p-type Ga formed on the 1-x'11xAs layer 6
a Surface of the As layer 7.

and p-type 1 on the back surface of the n-type GaAs substrate 1, respectively.
' An electrode 8 and an n-type electrode 9 are provided. In the structure shown in FIG. 1 above, the light generated in the GaAs active layer 3 is absorbed by the n-type GaAs layer 4 outside the stripe region 5, so the effective refractive index is different between the inside and outside of the stripe region 5. A difference occurs and transverse mode control is performed. 2°・3・However, polarity reversal occurs in the n-type GaA, s layer 4 due to the above light absorption, so it works effectively as a current confinement layer.

[Objective of the Invention] The present invention provides a transverse mode control laser device with a low threshold current value and a method for manufacturing the same, which is manufactured by an organometallic vapor phase epitaxy method. The purpose is to

[Summary of the invention]

In order to achieve the above object, the present invention sequentially forms 1st to 51'' semiconductor layers each having a predetermined forbidden band width and conductivity on a semiconductor substrate, and processes and etches the semiconductor layers described above. A stripe-shaped trench is formed from the surface of the semiconductor layer No. 5 to the surface or inside of the third semiconductor layer, and after filling the upper trench by metal organic vapor phase epitaxy, a sixth semiconductor layer is formed. By 1-., the light absorption layer of the fourth semiconductor layer and the current confinement layer of the fifth semiconductor layer are provided independently and sequentially, thereby achieving a low threshold that has sufficient current confinement and effect as well as transverse mode control effect. This is to obtain a semiconductor laser device with a current value and its manufacturing method.”
・14・ [Embodiments of the invention] Next, embodiments of the present invention will be described with reference to the drawings. .

FIG. 2 is a sectional view showing the structure of an embodiment of a semiconductor laser according to the present invention. An n-type Ga1-x AJ, A is a first semiconductor layer on an n-type GaAs substrate 11, which has a larger forbidden band width than the substrate 11 and has the same conductivity 5 as the substrate.
s' cladding layer 1.2 (x = 0.45, thickness 1
μm), and the second semiconductor layer has a smaller forbidden band width than the first semiconductor.

Ga1-y A, 1yAs active layer 1.3 (y =
The third semiconductor layer is p-type Ga, which has a forbidden band width of 0.14 μm and a thickness of 0.06 to 0.08 μm, which is larger than that of the second semiconductor layer, and has conductivity opposite to that of the substrate. , -z A7
17As cladding layer 14 (z = 0.3 to 0.44
, -thickness of 0.4 to 06 μm) and Ga, which is the second semiconductor layer and the fourth semiconductor layer with a smaller forbidden band width, -u
AluAs light/absorption layer 15 (u = O ~ 0.1,
The fifth semiconductor layer has a thickness of 0.3 ttm) and a forbidden band width 1) which is larger than that of the second semiconductor layer and has the same conductivity as the substrate.Current confinement Layer 16 (v = 0.45, thickness 0.5-11
tm) and a Ga-As layer (thickness 0.5 μm),
They are formed sequentially by liquid phase epitaxy or organic/metallic vapor phase epitaxy. After forming the 8102 film on the surface of the 50th semiconductor layer 16, photoresist is applied.

Through the etching process and the etching process, striped windows with a width of 3° to 5 μm are formed in the 5102 film. Next time.

Etch the crystals in the window area with a phosphoric acid-based etching solution.

At this time, the etching depth is n-type Ga, -
vA, l A, 0 sequence to advance halfway through the s layer 16.

■ Remove n-type Ga from the above window using HF-based etching solution.
1- Selective etching of yAlyA, 8 layer 16 and its removal.

The 8102 film on the surface is also removed at the same time. Next is phosphoric acid.

1°1 exposed in stripes using etching solution
Ga1-uA71uAS light absorption layer 15 and Ga1. A, a part of the 17As cladding layer 14 was etched, and the Ga A was formed on the crystal surface at the same time.
, remove the S layer by metal-organic chemical vapor deposition into the etched grooves.

p-type Ga1. -wA7! wAS layer (w = 0
．． 3-045) into 1) embedding, p-type Ga1. -WA～A
The sixth semiconductor layer 17 consisting of the s-layer is replaced with the fifth semiconductor layer 1.
After forming the p-type Ga Ass layer 1 on the p-type Ga Ass layer 1, the surface of the p-type Ga Ass layer 1 and the n-type GaA
P-side electrode (・Or −Au) on the lower surface of the s-substrate 11
1.9 and n-side electrode (Au-Ge-Ni-Au)
Form 20 pieces. Next, a resonator is produced through a cleavage process.

0 manufactured a semiconductor laser device with a length of 300 μm.

The semiconductor laser device has an oscillation wavelength of 780 nm.

Then, continuous oscillation is performed at room temperature with an oscillation threshold current value of 30 to 40 mA.

Ta. In addition, the laser transverse mode is stable up to an optical output of 30mW.
It turned out to be basic mode. Furthermore, the environmental temperature is ゛70
The optical output of the above semiconductor laser device at ℃ is 20 mW.
As a result of constant light output operation with ``, it was found that ``has high reliability with no noticeable deterioration after 3000 hours of operation.'' 10 In the above example, the Ga A, l As laser device was described. However, it goes without saying that the semiconductor/solid state laser device according to the present invention can be realized using other material systems as well.Although this embodiment describes a single semiconductor laser device, multiple semiconductor laser devices can be used in the same chip. Laser arrays in which 1) elements are arranged 1) and phased arrays in which nonlinear interaction of light is created between a plurality of adjacent elements can also be realized with the structure according to the present invention. Furthermore, in the above embodiments, the case where the active layer is composed of a single layer has been described, but in the case where the active layer is composed of a superlattice made of ultra-thin films of two or more substances.

Also, a semiconductor laser device according to the present invention can be realized.

I can do that.

〔Effect of the invention〕

In the present invention, as described above, the first to fifth semiconductor layers each having a predetermined forbidden band width and conductivity 5 are sequentially formed on a semiconductor substrate, and the fifth semiconductor layer is etched. of the third semiconductor layer from the surface.

Striped grooves that reach the surface or its interior.

By forming the above-mentioned groove 10 and forming the sixth semiconductor layer by organometallic vapor phase epitaxy, the light absorption layer and the current confinement layer were independently provided one after another. Since complete current confinement can be achieved along with the transverse mode effect, a semiconductor laser/device with a low threshold current value can be obtained. 1)

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing the structure of a semiconductor laser manufactured by a conventional metal organic vapor phase epitaxy method, and FIG. 2 is a sectional view showing the structure of an embodiment of the semiconductor laser according to the present invention. 2...11...Semiconductor substrate, 12...First semiconductor layer, 13...Th. 2 semiconductor layer, 14... third semiconductor layer, 15...
Fourth. Semiconductor layer, 16...5th semiconductor layer, 17...6th semiconductor layer
0 semiconductor. Level 0 Representative Patent Attorney Junnosuke Nakamura ”0 1F 1-2 Figure q

Claims (2)

[Claims] (1) A first semiconductor layer formed in sequence on a semiconductor substrate and having a bandgap larger than the substrate and the same conductivity as the substrate, and a second semiconductor layer whose bandgap is smaller than the first semiconductor layer. The layer and forbidden band width are the 20th semiconductor. a thirteenth semiconductor layer which is larger than the body layer and has a conductivity opposite to that of the substrate; and a fourth semiconductor layer whose forbidden band width is smaller than that of the second semiconductor layer.
a second semiconductor layer having a larger forbidden band width than the second semiconductor layer and having the same conductivity as the substrate; and a striped groove extending from the surface of the fifth semiconductor layer to the surface of the third semiconductor layer or the inside thereof, and formed within the groove and on the surface of the fifth semiconductor layer other than the groove. and a sixth semiconductor layer having a forbidden band width larger than that of the second semiconductor layer and having the same conductivity as the third semiconductor layer. (2) The forbidden band width on the semiconductor substrate is larger than that of the substrate. a first semiconductor layer having the same conductivity as the substrate; a second semiconductor whose forbidden band width is smaller than that of the first semiconductor layer; the above-mentioned layer, and the forbidden band width is larger than that of the second semiconductor layer. a third semiconductor layer having conductivity opposite to that of the substrate; and a fourth semiconductor having a smaller forbidden band width than the second semiconductor layer. the above-mentioned layer, and the forbidden band width is larger than that of the second semiconductor layer. a fifth semiconductor layer having the same conductivity as the substrate; A step of sequentially forming the fifth semiconductor layer by a liquid phase epitaxy method or a metal organic vapor phase epitaxy method, and a step of forming a third semiconductor layer 1' from the surface of the fifth semiconductor layer.
A forbidden band width is formed in the groove and on the fifth semiconductor surface other than the groove by an etching process to form a strip-shaped groove reaching the surface or inside of the semiconductor layer, and an organic metal/metal vapor phase epitaxy method. A method for manufacturing a semiconductor device, comprising: 1) forming a sixth semiconductor layer having the same conductivity as a second semiconductor layer and a third semiconductor layer.