JPS5812386A - Manufacture of semiconductor laser element - Google Patents

Abstract

PURPOSE:To form a laser element having double heterojunction structure according to the liquid phase epitaxial growth method by a method wherein crystal layers of an active layer and a top layer having the desired composition are enabled to be obtained by making SSe and S being the easily evaporable components are made to be molten in a liquid phase of Pb of the prescribed quantity. CONSTITUTION:A P type PbS substrate 2, a PbS1-XSeX thin plate 3 for dummy being the compound of easily evaporable selenium sulfide (SSe) and Pb, and a lead sulfide (PbS) thin plate 4 for dummy being the compound of sulfur (S) and Pb are buried in a supporting base plate 1 consisting of carbon, for example. While Pb is filled up in sliding members 5, 6, and 7 to transfer on the supporting base plate. After the liquid phase epitaxial growth device like this is inserted in a reaction tube in the hydrogen (H2) gas atmosphere, the reaction tube is heated at the temperature of 500 deg.C in a heating furnace, and the member 5 is transferred in the direction shown with an arrow mark A when Pb is molten. Accordingly the P type PbS1-XSeX crystal layer introduced with SSe is formed as the crystal layer of the active layer 11 of the first layer, and the P type PbS crystal layer is formed as the crystal layer of the top layer 12 of the second layer on the PbS substrate 2.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a method for manufacturing a semiconductor laser device.

Compound semiconductors containing lead (P't), such as lead telluride (
, PI) Tθ) and lead tin telluride (Pb1-x5nzTe
) and lead-sulfur-selenium (pbsl-Xsex), etc.
Due to its narrow energy gap, it is used as a material for infrared semiconductor laser devices.

In particular, a laser element using Pb5l-XseX material is
- Infrared light source element for spectroscopic analysis of gases that generate pollution, such as nitrogen oxide (No) gas and nitrogen dioxide (NOg) gas, because it oscillates in the 4-8 μm band that matches the absorption peak wavelength of those gases. It is used as.

By the way, in general, sulfur (S) and selenium (Se) among the PbS 1-zsez materials have high vapor pressure and are easily evaporated components, so it is not possible to apply the liquid phase epitaxia growth method using the 7-riding method. This is difficult, and conventional laser devices of this type have been constructed as single heterojunction diode lasers that utilize interdiffusion.

In other words, in the conventional technology, a crystal layer of P'l)S 1-zsez is formed as an active layer on a substrate of lead sulfide (pbs), and a crystal layer of K pbs is further formed as an F layer on top of the active layer. The laser beam generated in the active layer is confined in the hetero interface between the active layer and the substrate and the active layer and the top layer to initiate so-called laser oscillation, and is a highly efficient double hetero type laser with a small 01/1 value current. It was difficult to obtain the device.

The present invention aims to provide a method for manufacturing a semiconductor laser device that eliminates the above-mentioned drawbacks. This paper proposes a method for realizing a laser device using the liquid phase evaporation method. Briefly stated, the present invention utilizes S-? By dissolving SSe into Pbm, the loss of S and Be is suppressed and liquid phase epitaxia μ growth is made possible. The manufacturing method of the present invention includes a lead-containing compound semiconductor substrate and a dummy thin plate made of a compound of lead and an easily evaporated component among the components constituting the crystal layer to be laminated on the substrate. Providing a liquid reservoir filled with a liquid phase of lead corresponding to the number of crystal layers to be formed on the substrate, embedded in the same number of crystal layers to be formed on the substrate, and provided on a slide member that slides and moves on the support base. The liquid reservoir is moved onto a dummy thin plate and
The easily evaporable components of the thin plate for the dummy are dissolved in the liquid phase of lead,
After that, the liquid reservoirs are sequentially moved onto the substrate and left standing,
The method is characterized in that it includes a step of lowering the temperature of the liquid phase and sequentially stacking crystal layers on the substrate.

An embodiment of the present invention will be described in detail below with reference to the drawings.

FIG. 1 is a schematic diagram of an apparatus for forming a semiconductor laser device of the present invention, and FIG. 2 is a cross-sectional view of the material of the semiconductor laser device formed by the method of the present invention.

As shown in the figure, a support base 1 made of carbon, which constitutes a liquid phase epitaxial growth apparatus, includes a substrate 2 of, for example, P-type PbS, selenium sulfide (SSe), an easily evaporable component, and Pb.
A dummy thin plate 8 of a compound of Pb5l-xSθX and a dummy thin plate 4 of lead sulfide (pbs) of a compound of sulfur (S) and pb are buried.
Thallium (T#), which is a Pm dopant, is added to the Pm dopant. Meanwhile, the liquid phase epitaxial growth apparatus is configured,
The slide member 6 that moves on the support table is provided with a liquid reservoir 6.7 containing a PbO liquid phase, and the liquid reservoir is filled with Pb.

Here, the dummy thin plate 8 of the front 11i3pbssθ and PbS
The dummy thin plate 4 is formed by using the Bridgman method or the like to prevent the easily evaporable components S and Se from evaporating.

Hydrogen (H8)
) After being inserted into a reaction tube in a gas atmosphere, the cough reaction tube is heated to a temperature of 600° C. in a heating furnace.

In this way, when the PB in the liquid reservoir of the slide member is dissolved, the slide member is moved in the direction of arrow A.

The soaking liquid reservoir 6 is moved onto a dummy thin plate 8, and the liquid phase of PB in the liquid reservoir 6 is saturated with the selenium sulfide (SSe) component of the PBSSE thin plate 8. At this time, the Pb liquid phase in the liquid reservoir 7 is moved onto the dummy thin plate 4, and the S component of the PI)S thin plate 4 is saturated with the Pb liquid phase in the liquid reservoir 7. .

Thereafter, the sulphide member is further moved in the direction of arrow A, and the liquid reservoir 6 is left still on the PbS substrate 2, and the temperature of the heating furnace is further lowered at a predetermined temperature gradient to create a supersaturated state on the substrate 2. A component of PbSSe is precipitated as a first active layer to form Pm PbS 1-xsθX crystals.

Thereafter, the slide member was further moved in the direction of arrow A while lowering the temperature of the heating furnace at a predetermined temperature gradient, and the liquid reservoir 7 was left still on the substrate 2, so that the PbS which became a supersaturated state on the substrate 2
The components of P-type p'b are precipitated as the top layer of the second layer.
form a crystal of s.

In this way, as shown in FIG. 2, the easily evaporable component SSe is introduced onto the PbS substrate 2! pbs
A crystal layer of 1-2 sez is formed as the crystal layer of the first active layer 11, and on top of that, a PfJ p'bs crystal layer into which S, an easily evaporable component, is introduced is the top layer of the second layer. 1
A material for a dead conductor laser element is obtained.

Furthermore, according to the method of the present invention, Pb5l-7s61 in the active layer
In order to change the S and Sθ composition ratio (X value) in the X crystal layer, the content of SSe contained in the Pb5l-zSez dummy thin plate described above may be determined in advance to a predetermined value.

(9) In order to use an N-type PbS substrate as the substrate and impart a Nm conductivity type to the active layer and top layer, bismuth (B1) impurity to impart an N5 conductivity type to the dummy thin plate 8.4 is added. The impurity can be easily added if it is added in advance. In this way, P-type and N-type impurities can be easily added at a predetermined concentration.

As described above, according to the method of the present invention, easily vaporizable components such as SSe and S are dissolved in a predetermined amount into the pbO liquid phase, and an active layer and a top layer crystal layer having a desired composition can be obtained. This brings about the advantage that a semiconductor laser device having desired characteristics can be obtained.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram of an apparatus used to carry out the method of the present invention, and FIG. 2 is a cross-sectional view of a material for a laser element formed by the method of the present invention. In the figure, 1 is a support stand, 2 is a substrate, and 8 is Pb5l-XS
eX dummy thin plate, 4 Pt)S dummy thin plate, 6
is a slide member, 6.7 is a liquid reservoir, tt is an active layer, 12
is the top layer, and A is an arrow indicating the sliding direction.

Claims (1)

[Claims] A compound semiconductor substrate containing lead on a support base, and the number of crystal layers to form a dummy thin plate made of a compound of lead and an easily evaporated component among the components constituting the crystal layer to be laminated on the substrate. A slide member that slides and moves on the support base is provided with a liquid reservoir filled with lead liquid phase equal to the number of crystal layers to be formed on the substrate, and the liquid reservoir is used as a dummy. The easily evaporable components of the dummy thin plate are dissolved in the lead liquid phase by moving the liquid onto the thin plate, and then the liquid reservoirs are sequentially moved onto the substrate and left standing to lower the temperature of the liquid phase. 1. A method of manufacturing a semiconductor laser device, comprising the step of sequentially stacking crystal layers on a substrate.