JPH01301598A - Uniformizing method of characteristic property of compound semiconductor single crystal - Google Patents

Abstract

PURPOSE:To uniformize various properties such as electric, electronic and optical properties of above single crystal with easy heat-treating process, by covering a compound semiconductor single crystal with powder of said single crystal, heating and cooling. CONSTITUTION:In case of heat treatment of a compound semiconductor single crystal, ingot or wafer of said single crystal, etc., is covered with powder of the same kind as said single crystal. Powder having fine particle is used as said powder and a contact of said powder with the crystal is preferably kept in a good state. In a concrete example, a single crystal wafer 3 is set in a quartz ample 1 and powder 2 of the same kind as the single crystal is simultaneously filled in the ample 1, sealed in vacuum and heat-treated of heating-cooling keeping said state, as exemplified in the figure. By said process, various above- mentioned properties of a compound semiconductor single crystal are effectively uniformized.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method for homogenizing the electrical, electronic, optical, etc. properties of a compound semiconductor single crystal.

(Prior art) Semiconductor substrate crystals made by the liquid-filled Czochlaski method (LEC method) or the horizontal Bridgman method have various characteristics such as electrical characteristics within the (100) plane used in integrated circuits. It is usually unevenly distributed. As a method for homogenizing these characteristics, a method has been proposed in which a GaAs single crystal is heat-treated in an As atmosphere.

(The problem that the invention seeks to solve!) When heat-treating a compound semiconductor single crystal, for example, Ga
In the case of As single crystal, As is removed from the surface of the ingot and wafer.
Therefore, in the conventional method, heat treatment is performed in an As atmosphere to prevent As from coming out. However, with this method, it is difficult to control the As pressure and handle poisonous substances.

The present invention provides a method for effectively homogenizing the properties of a compound semiconductor single crystal using a simple heat treatment operation.

(Means for Solving the Problems) According to the present invention, when a compound semiconductor single crystal is heat-treated, an ingot or wafer of the compound semiconductor single crystal is covered with powder of the same type as the single crystal. It is preferable to use powder with small particles to ensure good contact with the crystals. Furthermore, it is preferable to use a sufficient amount of powder to cover the wafer or ingot, to minimize contact with the gas phase, and to prevent As and the like from coming off the surface. Further, the composition of the compound semiconductor powder may be one in which the component having a higher vapor pressure is increased compared to the composition of the single crystal ingot or wafer. The heating-cooling heat treatment involves heating-cooling.

In the heat treatment step, the compound semiconductor single crystal only needs to be covered with the same type of powder as the single crystal at least in a temperature range where evaporation of the single crystal components occurs.

In FIG. 1, a single crystal wafer 3 is placed in a quartz ampoule l, and the ampoule is filled with powder 2 of the same type as the single crystal.
It is sealed in a vacuum, and heat treatment of heating and rapid cooling is performed in this state. Further, as shown in Fig. 2, the wafer 3 is covered with the same kind of powder and the whole is compressed to form a pellet, which is then filled into a quartz ampoule l with the same kind of powder 2 as the single crystal and sealed in a vacuum. Also good. This further prevents the wafer from coming into contact with the gas phase.

Furthermore, the effects of the present invention can be enhanced by making the volume of the gas phase in the ampoule as small as possible.

Instead of wafers, single crystal ingots may also be used, which is advantageous from an industrial point of view.

(Example) Raw material for growing GaAs single crystal (polycrystalline GaAs)
The processed wafer, which covers the entire wafer processed into powder and processed into 6 x 6 x 0.5 (mm), is 3H, So, :
H, O,: The surface is etched with an etching solution having a ratio of H, O.
Use one that has been etched by about m. As shown in FIG. 1, it is vacuum sealed in a quartz ampoule, heated at 950'K for 46 hours, and then rapidly cooled. After etching by 50 μm with the above-mentioned etching solution and measuring the electrical characteristics, the resistivity was 3X10"n2X10"Ω'cm and the carrier concentration was 6X10'cm-'-+I X I Oocm-.
"Became.

For comparison, when not covered with powder, the resistivity is 1 x 10'
Ω'cm, and the carrier concentration was 2X I O "am-", which clearly resulted in the removal of As from the wafer surface, indicating that the present invention is effective in preventing the removal of As.

(Effects of the Invention) According to the present invention, various electrical, electronic, optical, etc. properties of a compound semiconductor single crystal can be efficiently controlled with easy operations.

[Brief explanation of the drawing]

1st [i! l, 2nd rl! J is a partially cutaway front view of a quartz tube ampoule showing the method of the present invention. Explanation of symbols 1, quartz tube ampoule 2, powder of the same type as the single crystal 3, single crystal wafer) Powder 3 single crystal wafer

Claims (1)

[Claims] 1. A method for homogenizing the properties of a compound semiconductor single crystal, which comprises covering the compound semiconductor single crystal with powder of the single crystal, heating it, and then cooling it.