JPS5810876B2 - handout - Google Patents

Description

[Detailed description of the invention] The present invention relates to an injection type semiconductor light emitting device.

A semiconductor laser device is a typical example of a semiconductor light emitting device.

The present invention will be explained by citing the following examples.

Semiconductor lasers often have a striped structure for the purpose of lowering the oscillation threshold.

Figure 1 shows a typical example of an oxide stripe laser, where 1 is n-Ga0.7A10.
3As, 2 is P-GaAs, 3 is PGao, 7A10.
3As, 4 is P+-GaAs, 5 is n-GaAs substrate,
6 is an Au-Ge alloy layer, 7 is an Au-Zn alloy layer, 8 is S
iO2 film, 9 is heat mink, fourth layer P+-Ga
A part of the As4 film is left in a stripe shape and the other part is covered with a SiO2 film 8, so that the current is confined in the light emitting region directly under the stripe.

Although this structure is easy to manufacture, it has the following drawbacks.

First, when using a laser at room temperature due to the difference in thermal expansion coefficient between the SiO2 film 8 and the p+-GaAs4 directly below it, the stress generated at the interface causes the active region P-G of the laser element to
Strain is introduced into aAs2, which contributes to shortening the lifetime of the laser.

Next, the heat generated in the active region 2 escapes through the SiO2 film 8 side, the film side, and the sink 9, but the SiO2
Since the thermal conductivity of the membrane 8 is very low, heat can only escape through the striped portions, resulting in very poor thermal conductivity.

In order to solve the above-mentioned drawbacks, as shown in FIG.
An n-Ga1-2AlzAs epitaxial film 10 is used instead of the O2 film 8, and the n-G film is formed except for the stripe portion.
A conceivable structure is to confine the current in the active region directly under the stripe by utilizing the fact that a1-2AlzAs10 and p+-GaAs4 are biased in opposite directions.

Although this structure can greatly improve the drawbacks of the above-mentioned oxide stripe type laser, it is not easy to manufacture, and problems remain in terms of heat dissipation.

Therefore, the present invention further provides a sweep-type laser with improved distortion and thermal resistance.
Instead of the Ga1-zAlzAs epitaaxial film 10, a high-resistance GaAs polycrystalline layer 15 is deposited at a low temperature to form the stripe portion.

The present invention will be described in detail below with reference to Examples.

Embodiment FIG. 3 shows a method for manufacturing a semiconductor laser according to an embodiment of the invention, in which the same parts as in FIGS. 1 and 2 are given the same numbers. n-G using the usual liquid phase epitaxial sliding method.
a0.7A10.3As1゜P-GaAs2. P-Ga
0.7A10.3As3. P+-GaAs4, 7 each
μ, 0.5μ, 1μ, and 2μ grow (Fig. 3a).

Next, a SiO2 film 8 is placed on the P+-GaAs4 at a thickness of 5000A.
(1,10) using photo-etching technique.
The 5i02 films 8 having a width of 10 μm are left at intervals of 250 μm in the direction, and the remaining 5i02 films are removed (FIG. 3(b)).

Next, 0.5 μm of high-resistance GaAs polycrystal 15 is deposited on the portion where the SiO2 film has been removed.

In this example, trimethylpotassium (Ga(CH3)3)
Polycrystalline GaAs 15 was deposited using a thermal decomposition method using alumina (AsH3) as raw materials.

The substrate temperature was kept at 300° C. or lower to ensure adhesion as low as possible.

This is to prevent distortion from occurring on the substrate side during adhesion.

The 15 GaAs films deposited under these conditions had a high resistivity of approximately 10:3 Ωcm (Figure C).
.

Next, the SiO2 film 8 is removed using a mixed solution of hydrofluoric acid and ammonium fluoride (d in the same figure).

Lapping the n-GaAs substrate 5 to reduce the total thickness to 10
After reducing the thickness to 0 μ, Au-Ge alloy 6 is deposited on the n-GaAs substrate 5 side, and Au-Zn alloy 7 is deposited on the polycrystalline GaAs 1S side by vacuum evaporation (e) in the same figure, so that the stripe part is exactly centered ( A laser chip is completed by scribing at 250μ intervals and breaking at 400μ intervals in the cavity direction.

By attaching this to the copper block 9 upside down, a laser device is completed (FIG. 4(f)), and its characteristics are as follows.

Since the GaAs 15 is first deposited at a low temperature, there is no fear of distortion due to differences in thermal expansion coefficients as in the oxite drive type laser shown in FIG.

In addition, GaAs has a thermal conductivity of SiO2 film 8 and Ga1-2A.
Since it is higher than lzAs 11, the heat generated in the active region 2 can be considerably dissipated not only through the stripe portion but also through the polycrystalline GaAs 15, so it is excellent in terms of heat conduction.

Further, since the polycrystalline GaAs 15 can be easily attached to the extent that the SiO2 film 7 is attached, the manufacturing ease is also comparable to that of an oxide stripe type laser.

As in the embodiments described above, the striped laser according to the present invention has many features compared to conventional lasers.

Although polycrystalline GaAs was used in the above embodiment, other Ga1
-xA1xAs (0<x≦1) and GaAs1-XPX (
0≦x≦1) may be attached.

However, at this time, heat conduction becomes a little worse.

In addition to the above-mentioned vapor phase growth method, a good high-resistance polycrystalline film can also be produced by depositing CdS, Zn5e, etc., which are group compounds of the 1-2 group, using a vacuum evaporation method or a sputtering method.

Of course, the above method can be applied not only to striped semiconductor lasers but also to general semiconductor light emitting devices.

[Brief explanation of drawings]

FIG. 1 is a schematic sectional view of a conventional oxide stripe type laser, FIG. 2 is a schematic sectional view of a conventional heterolysis stripe type laser, and FIGS. 3a to 3f are striped semiconductors according to an embodiment of the present invention. FIG. 2 is a schematic cross-sectional view of the structure of a laser. 1...n-Ga0.7A10.3As, 2...
...P-GaAs, 3...P-Ga0.7
A10.3As, 4...P+-GaAs, 5.
...n-GaAs, 6...Au-Ge alloy, 7...Au-Zn alloy, 9...heat sink, 15...many Crystalline GaAs.

Claims (1)

[Scope of Claims] An electrode semiconductor layer for injecting current into one light-emitting region, a stripe-shaped opening in contact with the electrode semiconductor layer, and a high resistance or conductivity type opposite to that of the electrode semiconductor layer. 1. A semiconductor light emitting device comprising: a polycrystalline semiconductor layer; and an electrode metal provided on the striped openings and the polycrystalline semiconductor layer. A step of selectively installing a polycrystalline semiconductor layer of high resistance or of a conductivity type opposite to that of the electrode semiconductor layer on one of the electrode semiconductor layers following the two light-emitting regions, and a step of selectively installing a polycrystalline semiconductor layer on the polycrystalline semiconductor layer and the exposed electrode semiconductor layer. 1. A method for manufacturing a semiconductor light emitting device, comprising the step of depositing metal for an electrode on a semiconductor layer to create a striped structure.