JPS60261184A - Semiconductor laser device and manufacture thereof - Google Patents

Abstract

PURPOSE:To form a semiconductor laser device, which is operated in a lateral basic mode by one crystal growth, by providing a stripe in the direction of an inverted mesa shape on a substrate and multiple-layer films having a double heterogeneous structure, which is formed by a growing method under a thermal unbalanced state. CONSTITUTION:On an n-GaAs semiconductor substrate 9, a region, which is higher than other parts, is formed in an inverted trapezoidal stripe shape in the direction of (110). Thereafter a Zn diffused layer 10 is provided. Then an n- Ga0.55Al0.45As clad layer 11, a GaAlAs active layer 12, a p-Ga0.55Al0.45As clad layer 13 and a cap layer 15 are sequentially laminated on both sides. In this constitution, a current flows only in the stripe because of the Zn diffused layer 10 held by the substrate 9 and the clad layer 11 or the substrate and the reverse conducting type formed layers. Since the growing speed of the crystal at a stepped part is slow, the active layer 12 at the stepped part is thinly grown. Light absorption by the active layer, which is not excited, does not occur. Leakage of carriers to the outside of the stripe becomes small.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a structure of a semiconductor laser device with a stabilized transverse mode and a method of manufacturing the same.

[Background of the invention]

An example of a conventional semiconductor laser device with stabilized transverse mode is shown in FIG. In the conventional example shown in FIG.
On top, n Ga 6 , 55 M 6 , 4 sA
s cladding layer 2, Ga,, @ @ M6, 14
AS active layer 3', p-Gao, sgAao, 45As
The cladding layer 4 and the p-GaAs cap layer 5 are crystal-grown, and the multilayer film is etched by a photoresist process using an ordinary oxide as a mask, leaving a stripe shape. p-Gas, ssM using the selectivity of liquid phase growth on the (GaAQ)As layer and on the (GaAQ)As layer. ,4. As layers 6 and n
-Gao, 5. An. ', a 4° As layer 7 is buried from both sides, and a p-GaAs cap layer 8 is further provided. However, in the case of such a structure, there are disadvantages in that defects in buried growth lower the yield and that crystal growth must be repeated twice.

[Purpose of the invention]

The present invention utilizes the shape of crystal growth in a thermal non-equilibrium state on stripes provided in the (110) direction on a GaAs substrate, can be formed in one crystal growth, and has low leakage current. It is an object of the present invention to obtain a semiconductor laser device whose oscillation mode operates in a stable transverse fundamental mode up to a high optical output. In a semiconductor laser device that performs transverse mode control by utilizing a step of a double heterostructure formed on a single conductive semiconductor substrate having a region higher than a portion thereof, a semiconductor laser device is provided on the substrate in an inverted mesa direction. By using a multilayer film with a double heterostructure formed by a growth method under thermal non-equilibrium conditions, it can be formed with a single crystal growth, has low leakage current, and has a stable oscillation mode up to high optical output. In this embodiment, a semiconductor laser device that operates in a transverse fundamental mode is obtained.

[Embodiments of the invention]

Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 2 is a view showing a scanning electron micrograph of an embodiment of the semiconductor laser device according to the present invention, and FIG. 3 is a sectional view showing an embodiment of the semiconductor laser device according to the present invention. Figure 2 shows M which is one of the crystal growth methods in a thermal non-equilibrium state.
This figure shows a cross section of a multilayer film formed using the same MOCVD method on a substrate on which convex stripes are provided in the (1''0) direction using the OCVD method. As shown in Figure 2, (
When etching is performed through a mask provided in the 110) direction using an etching solution such as a phosphoric acid-based etching solution whose etching rate is strongly dependent on the plane orientation, stripes having an inverted trapezoidal cross section as shown in the figure are obtained. Since crystal growth by MOCVD has a slow crystallization speed on the (111) plane, trapezoidal steps are produced on the stripes.

The embodiment shown in FIG.
An insulator mask with a width of 5-1 and a thickness of 0 is provided in the ) direction, and etched with a phosphoric acid-based etching solution to form an inverted trapezoidal striped region that is higher than other parts. , 1- Using the oxide mask as is, Z
Either by diffusing n and providing a Zn diffusion layer 10, or by selectively growing, for example, GaAs, only in areas of the substrate surface other than the inverted trapezoidal stripes using the above insulator as a mask, a layer having a conductivity type opposite to that of the substrate is provided, and then , n qao, 5sA9,.

, 45As crat layer 11 (2//Ill, n = 5
Xl017an-3), GaAQAs active layer 12
(0,06-), pGa,,9. Al10. ．． 5
As cladding layer 13 (2tIm, p=3X1017
an-3), pGan, 4AIlo.

6 layer 14, p-GaAs cap layer 15 (0,5p,
p = l Because of the diffusion layer 10 or the forming layer of opposite conductivity type to the substrate, the current flows only inside the stripes.
The difference in effective refractive index between the inside of the stripe and the outside of the stripe causes a difference in effective refractive index, and the laser light is guided inside the stripe. In addition, in such a structure, since the crystal growth rate in the step portion is slow, the active layer 12 in one step portion
The growth of the layer is about 0.01 mm, which makes it thinner than other parts, and light absorption by the unexcited active layer does not occur.
Because there is little carrier leakage to the outside of the stripe,
A semiconductor laser device with high optical output can be obtained. The semiconductor laser device according to this embodiment has a threshold current of 40 mA.
, continuous oscillation at room temperature with an oscillation wavelength of 780 nm, and an optical output of 50+
Stable transverse fundamental mode operation was performed up to nW.

- The above embodiment uses metal-organic vapor phase epitaxial method (M
(OCVD method), but other methods of crystal growth under thermal non-equilibrium conditions, namely molecular beam epitaxial method (MBE), were used.
Similar effects can be obtained by using a vapor phase epitaxy method (VPE method) or a vapor phase epitaxy method (VPE method).

〔Effect of the invention〕

As described above, the semiconductor laser device according to the present invention is a semiconductor laser device that performs transverse mode control using the steps of a double heterostructure formed on a semiconductor substrate having a striped region that is higher than other portions. , by providing stripes on the substrate in the reverse mesa direction and a double-hetero structure multilayer film formed by a growth method in a thermal nonequilibrium state, it is possible to By utilizing the shape of crystal growth, a structure that conventionally required two crystal growth processes can be formed in one crystal growth process, resulting in a horizontal oscillation mode with low leakage current and stable oscillation mode up to high optical output. A semiconductor laser device that performs mode operation can be obtained.

[Brief explanation of the drawing]

Figure 1 is a cross-sectional view of a conventional high-power semiconductor laser device, Figure 2 is a sectional view of a conventional high-power semiconductor laser device;
The figure is a cross-sectional view showing a scanning electron micrograph of a semiconductor laser device according to the present invention, and FIG. 3 is a cross-sectional view of the semiconductor laser device according to the present invention. 9...Semiconductor substrate lO...Zn diffusion layer 11-n-Gao, ssM. , 4 r, A S
Cladding layer 12-GaAAAs active layer 13-p-Ga, 55An. , Junnosuke Nakamura, patent attorney representing 45As cladding layer

Claims (3)

[Claims] (1) In a semiconductor laser device that performs transverse mode control by utilizing the steps of a double heterostructure formed on a semiconductor substrate having a striped region that is higher than other parts, What is claimed is: 1. A semiconductor laser device comprising: a stripe formed on the wafer; and a multilayer film with a double heterostructure formed by a crystal growth method in a thermal nonequilibrium state. (2) The semiconductor laser device according to claim 1, wherein the substrate has Zn diffused in advance on the surface of the substrate other than the stripes, or a layer having a conductivity type opposite to that of the substrate is provided. (3) In a method for manufacturing a semiconductor laser device that performs transverse mode control by utilizing the steps of a double heterostructure formed on a semiconductor substrate having a striped region that is higher than other portions, the stripe is Installed in the reverse mesa direction,
A method for manufacturing a semiconductor laser device, characterized in that a double heterostructure is formed by a growth method in a thermal non-equilibrium state.