JPS5930800A - Method for epitaxially growing pbtese single crystal in liquid phase - Google Patents

Abstract

PURPOSE:To carry out liq. phase epitaxial growth with no penetration of oxide by adding Te and Pb to a PbSe single crystal, melting them, and growing a layer of a PbTeSe single crystal using the melt. CONSTITUTION:Pb and Se are filled into a quartz ampul 11 and successively solidified from the tip B to form a single crystal 13 of a PbSe compound alloy. The PbSe alloy, Pb and Te are filled into a melt reservoir 5 for forming a buffer layer and a melt reservoir 7 for forming an enclosed layer, and materials for Pb1-xSnxTe are filled into a melt reservoir 6. A PbTe substrate 3 is fixed in a support 1, and the support 1 is heated in a reaction tube to form successively a buffer layer, an active layer and a containment layer on the substrate 3. By this method a PbTeSe single crystal of high quality suitable for use as a semiconductor laser element, etc. is epitaxially grown in a liq. phase.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Technical Field of the Invention The present invention relates to an improvement in a method for liquid phase epitaxial growth of a semiconductor single crystal made of PbTeSe.

(b) Technical background Compound semiconductor crystals containing lead, such as lead/tin/Te/V
(P'bl-zsnzTe), lead-sulfur-selenium (PbS1y,Sez), etc. have a narrow energy gap and are generally used as materials for photoelectric conversion elements such as infrared laser elements.

By the way, recently a compound semiconductor crystal of lead telluride (PbTf3) was formed as a buffer layer on a compound semiconductor crystal ball of lead telluride (PbTf3), and on top of that a compound semiconductor crystal of lead/tin/chill I (P'b1-xsnxTe) was formed.
A lattice-matched semiconductor laser device is formed by forming a compound semiconductor crystal as an active layer, and then sequentially forming a PbTe 1-Xsez crystal as a confinement layer thereon by a liquid phase epitaxial growth method.

In this lattice-matched laser device, the crystals forming the active layer, buffer layer, and confinement layer have approximately the same lattice constant, so there are fewer crystal defects due to lattice mismatch.
There is an advantage that the threshold current density for starting laser oscillation is reduced.

(C) Prior Art and Problems A conventional manufacturing method for such a lattice-matched semiconductor laser device will be described with reference to FIG.

FIG. 1 is a cross-sectional view of a liquid phase epitaxial growth apparatus for forming such a lattice-matched laser element. As shown in the figure, a PbTe substrate 8 is buried in a recess 2 of a support 1 made of rectangular parallelepiped carbon. has been done. One line support stand l
The slide member 4 that slides on the top thereof is provided with liquid reservoirs 5, 6゜7 in the form of through holes, and the PbTe1-zsez for forming the buffer layer to be formed on the substrate 3 is provided in the liquid reservoir 5.
material 8, and pbl-XS for active layer formation in the liquid reservoir 6.
The liquid reservoir 7 is filled with a material 9 of nXTe and a material 10 of PbTe 1-XSeX for forming a confinement layer.

Thereafter, a phase epitaxial growth apparatus consisting of a mixing support table 1 and a slide member 4 is inserted into a reaction tube containing hydrogen (H2) gas, and the reaction tube is heated in a heating furnace to form a liquid reservoir 5.6.
．． Melt the materials in 7.

After that, the slide member 4 is moved in the direction of the arrow, and the liquid reservoir 5 is placed on the substrate 3, and the humidity in the heating furnace is lowered to form a crystal layer of pb're1-)(SeX as a buffer layer on the substrate. Then, the slide member 4 is further moved in the direction of the arrow A, and after leaving the τ night pot 6 still on the substrate 3, the temperature of the heating furnace is lowered and Pb1-Xs is deposited as an active layer on the substrate.
A crystal layer of nzTe is formed.

After that, the slide member 4 is further moved in the direction of the arrow, and the board 8
After the liquid reservoir 7 was placed in the soil, the temperature of the heating furnace was lowered to form a crystal layer of PbTe1-X5eX as a confinement layer on the substrate.

Conventionally, as materials for forming buffer layers and confinement layers, lead (Pb), selenium (Se), and chill zv (Te) materials are weighed separately and filled into a liquid reservoir at predetermined weights, or Se. and Te are formed in advance in the form of an alloy, and this alloy of Se and Te and PI), T
The method used was to weigh each of e and e to a predetermined weight and fill it into a liquid reservoir.

However, in this method of mixing Se, Pb, and Te, filling the mixed material into a liquid reservoir, and melting the material, since Se is a material that is easily oxidized, oxides are easily removed from the solution. Produces debris that gets mixed into the surface or solution.

We also considered a method in which Se is melted with Te in advance to form an alloy of Se and Te, and then this alloy is mixed with Pb and Te in a predetermined amount, filled in a liquid reservoir, and melted. Even with this method, Se oxides tend to get mixed in on or in the solution in the liquid reservoir. If oxides of the material are formed on or in the solution in the liquid reservoir, evitaxial crystals may not grow on the substrate, or even if they can grow, evitaxial crystals will form, which is inconvenient for device formation with many crystal defects. This causes the inconvenience that it can only be formed.

(■ Purpose of the invention The present invention eliminates the above-mentioned drawbacks and provides a buffer layer.

The object of the present invention is to provide a novel method for liquid phase epitaxial growth of a PbTeSe crystal layer in which the above-mentioned oxides are not mixed into the solution in a liquid reservoir for forming a confinement layer.゛(e) Structure of the Invention The method of the present invention for achieving the above object uses a pre-formed single crystal of Pb5e as a material, and
The method is characterized in that a pb'rese single crystal layer is grown in a solution obtained by adding a predetermined amount of Pb and Te to a 5e single crystal and melting the mixture.

(j. Embodiment of the Invention Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.

FIG. 2 is a diagram for explaining the present invention in detail.

As shown in the figure, the method of the present invention involves weighing equal moles of PB and SE materials, filling them into a quartz ampoule 11 with a sharp tip B, and then evacuating the ampoule and melting one end. and seal.

Thereafter, the mixing amplifier 11 is lowered at a predetermined speed in the direction of arrow C into a vertical annular furnace having a temperature distribution as shown in 12, and the Pb and Se materials in the amplifier 11 are melted. A single crystal 13 of a pbse compound alloy is formed using the so-called Bridgman method in which the melt is sequentially solidified from the tip B of the amplifier I. In this way, unnecessary materials such as oxides of Se will remain in the melt 14 of Pb and Se, and will hardly enter into the solidified single crystal 13 from the tip B, resulting in high purity. A compound alloy of Pb5e is obtained, and Pb5e is difficult to oxidize even after alloy formation.

In addition, in the single crystal of Pb5e formed in this way, as shown in FIG. 8, there are many grain boundaries 15 that occur between crystals with different crystal growth directions. Since many impurities such as oxides of Pb and Se are segregated, it is preferable to remove these grain boundary portions to obtain a Pb5e alloy material.

Also, impurities such as oxides are more likely to enter the melt 14, and the closer to the tip B of the ampoule, the higher the purity of P with less oxides etc.
Since a single crystal of b5e is obtained, Pb5 near the tip B
By using a single crystal of e, a high quality material for forming a breadth layer and a confinement layer can be obtained.

A predetermined amount of the Pb5e compound alloy thus obtained was weighed, and then a predetermined amount of Te was also weighed to obtain the Pb5e compound alloy.
5e, Te, and PI) are filled into the buffer layer forming liquid reservoir 5 and the confinement layer forming liquid reservoir 7 shown in FIG. On the other hand, the liquid reservoir 6 was filled with pbl zsnzTe material, and the liquid phase epitaxial growth apparatus consisting of the support and the slide member was inserted into the reaction tube in the H2 gas atmosphere with the PbTe substrate buried in the support. The reaction tube is heated in a heating furnace.

In this way, as described above, the buffer layer, the active layer, and the confinement layer are sequentially formed on the pb're substrate and subjected to epitaxial formation to form a crystal layer.

In this way, almost no Se oxide is mixed in the solution for forming the buffer layer and the solution for forming the confinement layer, and therefore a high quality epitaxial crystal layer can be obtained. Forming a laser device has the advantage of increasing the yield of device formation.

■ Effects of the Invention As described above, according to the method of the present invention, a high quality epitaxial layer is obtained without contamination of the solution in the liquid reservoir with Se oxides, etc. Forming a laser device using a substrate has the advantage that a semiconductor laser device with good characteristics can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of an apparatus used in a conventional method for manufacturing a semiconductor laser device, and FIG. 2 is a schematic diagram showing an example of the process of the liquid phase epitaxial growth method of the present invention. 54. fy31+
i Pb5e, n 4 @ Schiff'shaku'fX, E Show J
1q is good. In the figure, 1 is a support stand, 2 is a recess, 8 Hpb're
, 4 is a slide member, 5, 6.7 are liquid reservoirs, 8 is a material for forming a buffer layer, 9 is a material for forming an active layer, 10 is a material for forming a confinement layer, 11 is an amplifier μ, and 12 is a temperature distribution , ■3 is a single crystal of Pb5e, 14 is a melt of Pb5e, 15 is a grain boundary, A is an arrow indicating the sliding direction, B is a tip, and C is an arrow indicating the moving direction of the ampoule.

Claims (1)

[Claims] A PbTeSe single crystal layer is formed on a lead-containing compound semiconductor crystal ball by using a solution obtained by adding a predetermined amount of Te and Pb to a Pb5e single crystal formed in advance and melting the resulting solution. A method for liquid phase epitaxial growth of crystals.