JPH0536733A - Manufacture of multi-component semiconductor crystals - Google Patents

Abstract

(57) [Summary] [Object] The present invention relates to a method for producing a multi-element semiconductor crystal made of Hg _1-x Cd _x Te, wherein the substrate and the crystal layer are less likely to warp when the crystal is grown and then cooled to room temperature. The purpose is to provide a method. A method for growing a multi-element semiconductor crystal containing Hg, Cd, and Te as component elements on a substrate 4 containing Cd, Zn, and Te as component elements by a liquid phase epitaxial crystal growth method. When the compositional ratio of Cd and Zn is (1-z): z, 0 <z <0.00
5 is satisfied.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing multi-element semiconductor crystals. Multi-element semiconductor crystal composed of multiple composition elements,
For example, one of the methods for growing a compound semiconductor crystal of gallium / arsenic, gallium / aluminum / arsenic, etc. on a crystal substrate is to bring a solution containing these semiconductors as a solute into contact with the crystal substrate at a high temperature and then gradually increase the temperature. There is a method in which a lowered semiconductor crystal is deposited and grown on a substrate.

This method is generally called a liquid phase epitaxial crystal growth method, and is widely adopted as a method for growing a single crystal having high purity and good crystallinity, particularly in the field of semiconductor industry. In recent years, compound semiconductor crystals such as mercury, cadmium, and tellurium containing lead, tin, tellurium, and easily vaporizable component elements have been used as a constituent material to manufacture photoelectric conversion elements such as infrared detection elements and infrared semiconductor laser elements. The above method is used.

[0003]

2. Description of the Related Art Conventionally, as a method for producing a multi-element semiconductor crystal for an infrared detection element, a multi-element semiconductor crystal made of Hg _1-x Cd _x Te is formed on a crystal growth substrate made of CdTe by a liquid phase epitaxial crystal growth method. A method for growing crystals is known.

Further, in order to improve the matching of the lattice constants at the hetero interface (the junction surface between the crystal growth substrate and the crystal layer), CdTe is used instead of the crystal growth substrate.
An improved method is known in which a crystal growth substrate made of _1-z Zn _z Te is used. In this case, z = 0.
By selecting the composition ratio of 03, the lattice constants at the hetero interface can be made substantially equal to each other, and the occurrence of crystal defects near the hetero interface can be prevented.

[0005]

In the conventional improved method of manufacturing a multi-source semiconductor crystal, when z = 0.03, it is possible to prevent crystal defects from being generated in the vicinity of the hetero interface. The following problems arise due to the difference in the coefficient of linear thermal expansion of the crystal layers.

That is, when a crystal layer is grown on a substrate at a high temperature of about 500 ° C. and cooled to room temperature, a hetero interface is formed due to the difference between the linear thermal expansion coefficient of the substrate and the linear thermal expansion coefficient of the crystal layer. Shear forces occur, causing the substrate and crystalline layers to bend. When this crystal layer is used for an infrared detection element, the crystal layer is cut out from the substrate or used by polishing, so that when the crystal layer is curved as described above, a composition distribution occurs in the obtained crystal plane. , Sensitivity characteristics, etc. become non-uniform.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a method for producing a multi-source semiconductor crystal in which the substrate and the crystal layer are less likely to warp when the crystal is grown and then cooled to room temperature. I am trying.

[0008]

According to the method for producing a multi-element semiconductor crystal of the present invention, a multi-element semiconductor crystal containing Hg, Cd, and Te as component elements is liquid-phase epitaxially deposited on a substrate containing Cd, Zn, and Te as component elements. In the method of growing a crystal by the crystal growth method, when the composition ratio of Cd and Zn which are the constituent elements of the substrate is (1-z): z, 0 <z <0.0.
It is something that satisfies 05.

[0009]

FIG. 3 is a graph showing the relationship between the linear thermal expansion amount (arbitrary unit) and the temperature (° C.) in the substrate and the crystal layer.
The linear thermal expansion amount of the substrate is based on three types of data with z as a parameter.

The solid line shows Hg _1-x Cd _x Te
This is for a crystal layer composed of (x = 0.26). The broken line located below the solid line indicates z
= 0 for the substrate. The broken line positioned above the solid line indicates z = 0.005.
The above is for the substrate. Further, the one-dot chain line shows the substrate when z = 0.026.

On the other hand, the curvature of the substrate and the crystal layer when the crystal was grown and cooled to room temperature was also investigated. z
When the substrate of = 0 and z = 0.005 was used, almost no curvature was generated in the substrate and the crystal layer. Also, z =
When using the 0.026 substrate, the substrate and crystalline layers were significantly curved, which was a problem.

From the above facts, 0 <z <0.00
It can be seen that by using the substrate satisfying the condition No. 5, it is possible to prevent warpage of the substrate and the crystal layer when the crystal is grown and then cooled to room temperature.

Cd _{1 -z} Z satisfying 0 <z <0.005
When a substrate made of _nz Te is used, a lattice defect may occur in the vicinity of the hetero interface due to a mismatch of lattice constants at the hetero interface. However, when the obtained multi-source semiconductor crystal is used for an infrared detection element, the hetero interface is used. By cutting off or removing the neighboring parts by polishing,
It is possible to prevent adverse effects due to crystal defects.

[0014]

EXAMPLES Examples of the present invention will be described below. FIG. 1 is an exploded perspective view of a jig or the like showing a preferred embodiment of the present invention.
This jig 1 has a notched recess 3 formed by cutting out a part of the center of the outer peripheral portion of a cylinder made of quartz glass in the direction of the central axis of the cylinder.
have.

The substrate 4 for crystal growth is, in this embodiment,
The substrate 4 is supported by a substrate holder 6 made of quartz glass, and by fitting the substrate holder 6 into the grooves 7, 7 formed on the opposite wall surfaces of the cutout recess 3, the substrate 4 is placed horizontally in the cutout recess 3. To be done.

The substrate 4 is made of Cd _1-z Zn _z Te, and the parameter z in the composition ratio (1-z): z of the component elements Cd, Zn satisfies 0 <z <0.005.
The jig 1 is inserted into the quartz ampoule 2 having an inner diameter slightly larger than the outer diameter of the jig 1, with the substrate 4 and the substrate holder 6 set as described above. At this time,
The melt material 5 together with the jig 1 is inserted into the quartz ampoule 2 so that the melt material is located in the notch recess 3. The constituent elements of the melt material 5 are Hg, Cd, and Te, and the composition ratio thereof is set according to the composition ratio of the multi-source semiconductor crystal to be manufactured.

Reference numeral 10 denotes a lid member for sealing the quartz ampoule 2, and the lid member 10 is made of quartz integrally with the exhaust pipe 11. After welding the lid member 10 to the end of the quartz ampoule 2, the inside of the quartz ampoule 2 is sucked into a vacuum through the exhaust pipe 11. After that, the quartz ampoule can be hermetically sealed by sealing the exhaust pipe 11 in the middle thereof, for example. The exhaust pipe 11 is also used to rotate the quartz ampoule 2 as described later.

The process of liquid phase epitaxial crystal growth in this embodiment will be described with reference to FIG. First, a quartz ampoule 2 in which a substrate 4 and a melt material 5 are enclosed together with a jig 1 is heated in an electric furnace to a predetermined temperature higher than a crystal growth temperature, and as shown in FIG. Ampoule 2
The melt material 5 therein is melted to form a melt material 5 '. At this time, the angle of the quartz ampoule 2 is adjusted so that the exposed surface of the substrate 4 faces upward on the horizontal plane.

Next, when the temperature inside the furnace is gradually lowered to the crystal growth temperature and the quartz ampule 2 is rotated 180 °, the jig 1 is also rotated 180 ° together with the quartz ampule 2. Since the liquid surface of the molten melt material 5'maintains a horizontal surface, the rotation of the quartz ampoule 2 causes the semi-column portion of the jig 1 to be embedded in the molten melt material 5 ', and the liquid surface of the molten melt material 5'. Rises and the substrate 4 facing downwards contacts the molten melt material 5 '.

When the molten melt material 5'contacts the substrate 4 at the crystal growth temperature, a crystal layer 12 made of Hg _1-x Cd _x Te grows on the surface of the substrate 4, as shown in FIG. 2B. To do.

After that, when the crystal layer 12 having a predetermined thickness is formed, as shown in FIG. 2C, the quartz ampoule 2 is rotated again by 180 ° so that the molten melt material 5'contacts the substrate 4. If not, the crystal growth is stopped.

Finally, although not shown, the quartz ampoule 2 is pulled out from the furnace while being gradually cooled to room temperature, the quartz ampoule 2 is opened, and the substrate 4 on which the crystal layer 12 is formed is removed from the substrate holder 6. ..

In this example, the parameter z representing the composition ratio of Cd and Zn, which are the constituent elements of the substrate, was 0 <z <.
Since it is set to satisfy 0.005, the growth layer 12
There is no possibility that the substrate 4 and the growth layer 12 may be curved when the substrate is grown and gradually cooled to room temperature. Therefore, when the infrared detection element is formed by cutting out the crystal layer, the composition of the crystal surface can be made uniform, and a detection element having a required uniform sensitivity characteristic can be realized.

In the process of FIG. 2B, the crystal layer 1
As the thickness of No. 2 increases, that is, as the time elapses, the temperature inside the furnace is gradually decreased, so that a composition gradient can be generated in the thickness direction of the crystal layer. As a result, the composition of the crystal surface can be set to a desired value depending on the cut-out position when separating the crystal layer from the substrate.

[0025]

As described above, according to the present invention,
It is possible to provide a method for manufacturing a multi-source semiconductor crystal in which the substrate and the crystal layer are less likely to warp when the crystal is grown and then cooled to room temperature.

[Brief description of drawings]

FIG. 1 is an exploded perspective view of a jig and the like showing a preferred embodiment of the present invention.

FIG. 2 is a process explanatory diagram of liquid phase epitaxial crystal growth in a preferred embodiment of the present invention.

FIG. 3 is a graph showing a relationship between a linear thermal expansion amount and a temperature in a substrate and a crystal layer.

[Explanation of symbols]

 1 jig 2 quartz ampoule 4 substrate 5 melt material 12 crystal layer

Continuation of front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display location H01S 3/18 9170-4M

Claims (1)

Claims: 1. A substrate containing Cd, Zn, and Te as constituent elements.
(4) In a method of growing a multi-element semiconductor crystal having Hg, Cd, and Te as component elements on the above by a liquid phase epitaxial crystal growth method, the composition ratio of Cd and Zn which are the component elements of the substrate (4) is ( 1-z): When z, 0 <z <0.005 is satisfied, The manufacturing method of the multi-element semiconductor crystal characterized by the above-mentioned.