JPH023620Y2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to a liquid phase epitaxial growth apparatus.
In particular, the present invention relates to a liquid phase epitaxial growth apparatus that can add various impurities in the vapor phase during liquid phase epitaxial growth and can simultaneously process large area substrates.

A conventional liquid phase epitaxial growth apparatus capable of adding impurities in the vapor phase during liquid phase epitaxial growth is constructed as shown in FIG. The substrate support 11, together with the solution storage reservoir 12 and the lid 13, are heated near the epitaxial growth start temperature,
The epitaxial solution 14 and the substrate crystal 15 are brought into contact with each other by relative movement to cause epitaxial growth, and necessary impurities are added from the gas phase through a large number of small holes 16 provided in the lid 13. . In FIG. 1, a shows the state before the solution 14 and the substrate crystal 15 are brought into contact, and b shows the state after the solution 14 and the substrate crystal 15 are brought into contact.

In this type of device, a large number of substrate crystals 15
If the length of the substrate support stand 11 is made to be approximately the same as the length of the uniform part of the axial temperature distribution of the electric heating furnace, a part of the lid body 13 will be located outside the uniform part of the temperature distribution. For this reason, the uniformity of the temperature distribution in the length direction of the substrate support 11 is impaired, resulting in the disadvantage that uniform epitaxial growth is not performed between the substrate crystals. Furthermore, if this type of growth apparatus is constructed of quartz or the like with little residual impurity contamination,
Since the substrate support 11 and the lid 13 are relatively moved over a long distance, there is a problem in handling that they are easily broken.

On the other hand, in the same type of growth apparatus shown in FIG. 2, the above-mentioned difficulties are eliminated. In the apparatus shown in FIG. 2, the substrate crystal and the epitaxial melt are brought into contact with each other in advance at room temperature, so the substrate support 21 and the lid 23 are not moved relative to each other during the epitaxial growth process. , the above-mentioned difficulties do not arise. However, in this type of growth apparatus, since the substrate crystal and the epitaxial melt 14 are brought into contact with each other at room temperature, the oxide film or organic film on the surface of the substrate crystal 15 or the surface of the melt 14 cannot be sufficiently removed. The contact between the substrate crystal 15 and the substrate crystal 15 is incomplete, resulting in a problem that good epitaxial growth cannot be performed.

An object of the present invention is to provide a liquid phase epitaxial growth apparatus that does not have the above-mentioned difficulties and can accommodate a large number of substrate crystals.

In the present invention, the substrate support table and the lid body having an opening at the top are fixed relatively to each other, and the length of the substrate support table and the length of the entire growth apparatus are approximately the same as the axial soaking section of the heating furnace. By making it possible to accommodate a large number of substrate crystals without compromising uniform heating,
The present invention is also characterized in that the epitaxial solution and the substrate crystal can come into contact at around the epitaxial growth start temperature.

Hereinafter, the growth apparatus of the present invention will be explained with reference to the drawings.

FIGS. 3 and 4 schematically show an embodiment of the liquid phase epitaxial growth apparatus of the present invention, in which a is a plan view and b is a top view of FIG. -C is a cross-sectional view taken along the line C-C' in figure a. This device is made of quartz, and includes a substrate container 31 and a spacer 3.
2. Solution lid 33, solution reservoir 34, and solution reservoir 34
A hole 35a is provided at the bottom of the spacer 32.
A hole 35b is also provided in the hole 35b, and the holes 35a and 35b can be connected to each other by relative movement of the solution reservoir 34 and the substrate container 31. The solution lid 33 is provided with a large number of openings 36 . When performing liquid phase epitaxial growth, the substrate 37 and the gallium solution 38 are placed in their respective predetermined positions, the solution reservoir 34 is positioned as shown in FIG. 3, and the hole 35a of the solution reservoir 34 is
and the hole 35b of the spacer 32 so that they do not match (connect), and then put into the reaction tube. After replacing the inside of the reaction tube with high-purity hydrogen gas, heating is started, the temperature is raised to the liquid phase growth starting temperature, and the temperature is kept for a predetermined period of time. After that, use the slide rod 39 to remove the solution reservoir 3.
4 so that the hole 35a of the solution reservoir 34 and the hole 35b of the spacer 32 match, and the solution 3
8 is poured into the space defined by the solution lid 33 and the substrate container 31. After a predetermined period of time, the mixture is cooled to a predetermined temperature at a predetermined cooling rate to obtain a liquid phase epitaxial layer. At this time, if a trace amount of hydrogen sulfide and ammonia gas are mixed into the atmospheric gas, the solution 3 will pass through the many small holes 36 provided in the solution lid 33.
Sulfur and nitrogen are added to 8 to obtain a nitrogen-doped n-type epitaxial growth layer. Next, the temperature is maintained for a predetermined period of time, the addition of hydrogen sulfide to the atmospheric gas is stopped, and the mixing of zinc vapor is started. Thereafter, slow cooling is restarted, and a nitrogen-doped p-type epitaxial layer is grown on the nitrogen-doped n-type epitaxial layer.

According to the embodiment described above, since the oxide film or organic film attached to the surface of the gallium solution 38 and the substrate 37 is exposed to a hydrogen atmosphere at high temperature,
Sufficient removal results in very good epitaxial growth. Furthermore, since the length of the entire boat is equal to the length of the substrate container 31, the length of the substrate container 31 can be made approximately the same as the soaking length of the heating furnace, and the storage capacity of the substrates 37 can be increased in the same furnace. It becomes possible to improve the performance.

[Brief explanation of the drawing]

Figures 1a, b, and 2 are schematic cross-sectional views of conventional liquid phase epitaxial growth equipment, and Figures 3 a, b, and c and Figures 4 a, b, and c are schematic cross-sectional views of liquid phase epitaxial growth equipment based on the present invention. FIG. 2 is a schematic cross-sectional view of a growth apparatus. 31...Substrate container, 32...Spacer, 3
3... Solution lid, 34... Solution reservoir, 35a and 35
b... Hole, 36... Opening part, 37... Substrate, 38
...Gallium solution, 39...Slide rod.

Claims (1)

[Scope of utility model registration request] A substrate accommodating body for accommodating a plurality of semiconductor substrates, a lid body having a plurality of small holes formed directly above the semiconductor substrates of the accommodating body via a predetermined space, and a melting body having holes formed in a bottom part other than directly above the semiconductor substrates. The liquid container and the melt container are moved a distance shorter than the length of the substrate container that accommodates one substrate, and the melt is introduced into the space through a hole in the container and a hole provided directly below the substrate container. A liquid phase epitaxial growth apparatus comprising: means for inserting a liquid to contact the semiconductor substrate; and means for adding impurities in a vapor phase through the lid and a plurality of small holes.