JPH0258769B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an epitaxial growth method and apparatus used to obtain a semiconductor crystal layer by a liquid phase epitaxial method.

Several methods have been considered for liquid phase epitaxial growth as one of the methods for growing semiconductor layers. FIG. 1 shows an outline of one such epitaxial apparatus using a melt drop type so-called slit boat.

In FIG. 1, reference numeral H denotes a support, and a container 18 for containing a substrate crystal is provided, and 19 indicates a semiconductor substrate. Reference numeral 12 denotes a reservoir with a hole at the bottom into which a raw material solution 17 for liquid phase epitaxial use is placed (a Ga solution containing the above components is used when growing thin films such as GaAs, GaP, Ga _{1-x Al} x As, etc.). 14 is a push rod for moving the slider, 15 is a weight for dropping the raw materials in the reservoir downward, and a lid for preventing volatilization. Reference numeral 13 indicates a slider having a holed reservoir at the top into which the raw material 16 after liquid phase epitaxial use is placed, and reference numeral 17 indicates a push rod for moving this slider. The epitaxial process using the above apparatus is as follows.

The push rod 14 is pushed, the slider 12 is moved, the raw material solution is dropped into the support 11, and brought into contact with the substrate 19.

After the desired thickness has been grown, the push rod 17 is pushed and the slider 13 is moved to drop the raw material solution into the reservoir and stop the crystal growth on the substrate.

In case of multiple growth, repeat this process.
Obtain multilayer crystals.

By the way, in this process, P-type Ga _1-x Al _x As, (x0.3), N-type Ga _1-y Al _y are formed on the P-type GaAs substrate.
A single heterojunction red light-emitting device has been obtained by growing As (y0.6) crystals, but there is in-plane non-uniformity in luminous efficiency and emission wavelength characteristics, and as a whole, the semiconductor device It is extremely uncomfortable when used as The causes of this in-plane non-uniformity of properties are (a) abnormal growth due to non-uniform contact with the substrate when the solution falls, and (b) oxide 20 contained in the solution.
etc., may fall and come into contact with the substrate, preventing growth.
etc. are possible.

An object of the present invention is to provide a new liquid phase epitaxial growth method and growth apparatus that eliminates the non-uniformity of characteristics such as luminous efficiency and emission wavelength caused by the conventional liquid phase epitaxial method as described above. .

In the conventional method, when the solution is dropped onto the substrate, it is dropped directly onto the substrate, which may cause abnormal growth due to non-uniform contact with the substrate when the solution falls, or oxides contained in the solution. 20 mag falls,
Because it adheres to the substrate and prevents growth, the properties of the resulting semiconductor device are non-uniform.

In this method, the raw material solution that comes into contact with the substrate is introduced from below to a constant thickness, thereby creating a uniform epitaxial layer without abnormal growth and preventing the incorporation of oxides, etc. .

FIG. 2 shows a semiconductor epitaxial growth apparatus relating to the method of the present invention. Figure 2a
2b shows the state before epitaxial growth, and FIG. 2b shows the state during epitaxial growth. The epitaxial apparatus shown in FIG. 2 has a lid x having a hole of the same size as the hole of the upper slider 22 in the crystal substrate holder part 28 of the support body 21, and the holder part is connected to the crystal substrate surface part and other parts. It has a spacer y that is connected to the bottom part of the spacer y. By pushing the push rod 24 as shown in Figure b, the slider 22
is moved, one of the raw material solutions 27 is brought into contact with this crystal substrate 29, and crystal growth is performed. At this time, the raw material solution 27 passing through the lid x on the top of the holder is
During the fall, it passes under the spacer y without contacting the substrate, enters between the spacer y and the crystal substrate 29, comes into contact with the crystal substrate 29, and starts crystal growth. Furthermore, at this time, oxides 20 and the like that adversely affect the device characteristics accumulate in the solution reservoir or above the spacer y, and crystal growth can occur in a state where they do not exist between the spacer y and the crystal substrate. .

Further, FIG. 2c shows an example in which, after the growth is completed, unnecessary raw material solution 26 is removed from the surface of the crystal substrate to prepare for growing a layer of a new composition on the crystal substrate 29. At this time, the oxides 20, etc. that adversely affect the device characteristics fall along the spacer y into the waste liquid reservoir, so they do not come into contact with the substrate, and there is no abnormal growth or crystals with different compositions, and a uniform Crystals can be obtained.

By repeating the same process, it is possible to obtain a second or higher crystal layer. Furthermore, by increasing the number of spacers and using some of the increased spacers as holders for the substrate crystals, it is possible to place a large number of substrate crystals, and it is possible to grow a large number of crystals at the same time.

The effects of liquid phase epitaxial growth according to the method of the present invention are as follows.

(1) The composition of the grown epitaxial layer is uniform,
No abnormal growth.

(2) The thickness of the grown epitaxial layer is uniform;
There are no abnormally grown protrusions.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing a conventional liquid phase epitaxial growth apparatus, and FIG. 2 is a diagram showing a, b, and c of the epitaxial growth apparatus and method of the present invention. 21...Support having crystal substrate holders 2, 8, 22...Slider having raw material solution reservoir, 29
...crystal substrate, 23...slider having a waste liquid reservoir,
x... A lid with holes through which the raw material solution passes, y... A spacer that separates the place where the raw material solution falls from the crystal substrate.

Claims (1)

[Claims] 1. Partitioned into three or more chambers in the vertical direction, the upper chamber is provided with a solution reservoir for accommodating the raw material solution, and the middle chamber is provided with a support body for accommodating the semiconductor substrate at an angle,
A method in which a waste solution reservoir for storing unnecessary raw material solution is provided in the lower chamber, and the solution is dropped from the solution reservoir in the upper chamber and brought into contact with the surface of a semiconductor substrate accommodated in the middle chamber to perform liquid phase epitaxial growth. Growth of an epitaxial layer of a semiconductor crystal, characterized in that epitaxial growth is performed by allowing the solution falling from the solution reservoir to reach the surface of the semiconductor substrate through a narrow gap on the back side of the semiconductor substrate. Method. 2. The method for growing an epitaxial layer of a semiconductor crystal according to claim 1, wherein the solution is made to reach the surface of the semiconductor substrate from the lower chamber side through a narrow gap. 3 Partitioned into three or more chambers in the vertical direction, the upper chamber is provided with a solution reservoir for containing the raw material solution, the middle chamber has a support body for accommodating the semiconductor substrate at an angle,
A waste liquid reservoir is provided in the lower chamber to accommodate unnecessary raw material solutions, and slits are provided at the bottom of the solution reservoir in the upper chamber and at the top of the support body that accommodates the semiconductor substrate in the middle chamber, and the slit positions are aligned. In a growth apparatus in which liquid phase epitaxial growth is performed by dropping a solution from a solution reservoir in an upper chamber into contact with the surface of a semiconductor substrate housed in a middle chamber, a narrow gap is provided on the back side of the semiconductor substrate, and the solution is An apparatus for growing an epitaxial growth layer of a semiconductor crystal, characterized in that the slit passes through a narrow gap and is brought into contact with the surface of the semiconductor substrate from the lower chamber side.