JPH04337627A - Vapor growth device - Google Patents

Abstract

PURPOSE:To provide a vapor growth device which can grow an epitaxial growth layer with a uniform thickness regardless of size differences in the growth substrate, not require the replacement of growth tools such as the reaction tube and the gas jet nozzle, and effectively use the source as without jetting an excessive amount of source gas for vertical vapor growth devices, especially MOVPE devices. CONSTITUTION:This device is designed with multiple gas spray outlets 51-5n which introduce the gas from one direction into the reation container and in the vapor growth device in which these gas jet outlets 51-5n are placed opposite a growth substrate 4, with a capability to independently switch the gas introduced to the reaction container through each individual gas spray outlet 51-5n between a 1st gas 1 which contains the growth material and a 2nd gas 2 which does not contain the growth material.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention relates to a vapor phase growth apparatus, particularly an MOVP used in manufacturing compound semiconductor epitaxial wafers for manufacturing light emitting and light receiving elements for optical communications.
The present invention relates to a vertical vapor phase growth apparatus such as an E (organic metal vapor phase epitaxial) apparatus.

In the production of epitaxial wafers, it is desired to obtain a uniform growth film thickness over a large area. Therefore, as a method to obtain a uniform grown film thickness, recently,
By using a vertical MOVPE device and blowing out the gas containing the growth material (growth gas) toward the growth substrate surface from multiple nozzles, disturbances in the gas flow due to gas convection and stagnation can be suppressed. A method has been proposed in which a laminar flow of the growth gas is realized on the growth substrate, thereby improving the uniformity of the grown film thickness.

However, although this method is sufficiently effective for growth substrates having fixed dimensions and shapes, there are cases where the dimensions of the substrate, such as the growth substrates used in the production of epitaxial wafers for optical devices, vary. When the shapes are different, such as circular, rectangular, large area, small area, etc., the growth gas consumption efficiency is lowered, defects occur, etc., and improvements are desired.

0004

[Prior Art] Fig. 3 is a schematic longitudinal cross-sectional view of a conventional vertical MOVPE apparatus, in which 1 is a gas supply pipe containing growth raw materials, 3 is a carbon susceptor, 3P is a substrate mounting groove, and 4 is a Growth substrate, 51 , 52 , 53 , 54 , 55
are gas blowing nozzles, 61 , 62 , 63 , 64
, 65 is a gas flow rate control means, 71 , 72 , 73
, 74 and 75 are stop valves, 11 is a vacuum exhaust port, 12 is a reaction vessel (reaction tube), and 13 is a rotation shaft for rotating the susceptor at a constant speed.

In conventional epitaxial growth using the same device, the substrate mounting groove 3 formed in the susceptor 3
The flow rate of the gas containing the growth material blown out from each nozzle 51 to 55 is controlled so that the thickness of the grown film on the growth substrate 4 that conforms to P is uniform, and the Either the gas containing the growth raw material is blown out from all the nozzles 51 to 55 under the same conditions to prevent gas convection and stagnation and epitaxial growth with a uniform film thickness is performed (first method); A method of growing with a uniform growth film thickness by replacing each growth substrate with a growth jig such as a reaction vessel (reaction tube) and a gas blowing nozzle that match the shape and size of the growth substrate (second method) ) was used.

[0006]

Therefore, according to the first method, when performing growth on a small substrate, an excess raw material gas that does not contribute to growth is flowed, which is uneconomical, and at the same time, The increase in decomposition products adhering to parts other than the substrate (mainly on the carbon susceptor) has caused a problem in that surface defects are likely to occur due to exfoliated and scattered particles of the decomposition products. Further, according to the second method, there is a problem that the throughput is reduced due to steps such as replacing reaction tubes, nozzles, etc., stabilizing the atmosphere, and setting conditions.

Therefore, the present invention aims to grow an epitaxially grown layer of uniform thickness regardless of the size of the substrate to be grown in a reaction vessel (
The purpose of the present invention is to provide a vapor phase growth apparatus that allows growth by effectively using raw material gas without replacing growth jigs such as reaction tubes and gas blowing nozzles, and without flowing excess raw material gas. .

[0008]

[Means for Solving the Problems] A solution to the above problem is to have a plurality of gas outlets for introducing gas from one direction into a reaction vessel, and a substrate to be grown to be grown facing the gas outlets. In a vapor phase growth apparatus, this book enables a first gas containing a growth material and a second gas not containing a growth material to be introduced into a reaction vessel by independently switching each gas outlet. This is achieved by a vapor phase growth apparatus according to the invention.

[0009]

FIG. 1 is a schematic diagram for explaining the principle of the present invention, in which (a) is a plan view showing the arrangement of gas blowing nozzles, and (b) is a schematic longitudinal sectional view of the main parts of the device.

As shown in this figure, in the vapor phase growth apparatus of the present invention, n gas blowing nozzles 5 are arranged, for example, on the same plane S of the upper wall surface, as shown in figure (a). As shown in Figure (b), each nozzle 5
1 to 5n Gas flow rate control means 61 in front of each
~6n are connected, and each gas flow rate control means 61 ~6n
are connected to the gas supply pipe 1 containing the growth raw material via first pipes 91 to 9n and first stop valves 71 to 7n, respectively. Furthermore, the first pipe 91 ~
9n, each has a second pipe 101 as a bypass.
~10n is connected, and this second piping 101 ~1
0n are second stop valves 81 to 8n, respectively.
It is configured to be connected to a gas supply pipe 2 that does not contain a growth material through a gas supply pipe 2.

In the vapor phase growth apparatus according to the present invention having such a configuration, when performing growth on the first growth target substrate 4 having a diameter L placed opposite to the nozzle surface,
The first stop valves 71 to 7n are opened, the second stop valves 81 to 8n are closed, and the gas containing the growth raw material is released and introduced from all the gas blowing nozzles 51 to 5n. An epitaxial layer with a uniform thickness is grown on the growth substrate 4. Thereafter, for example, when performing growth on a second growth target substrate 4' having a smaller diameter l than the first growth target substrate 4, a gas blowing nozzle, for example 53 to 5n-2, opposite to this substrate 4' is used.
The first stop valves 73 to 7n-2 corresponding to the above are opened, the second stop valves 83 to 8n-2 are closed, and the gas containing the growth raw material is introduced from these gas blowing nozzles 53 to 5n-2. Second growth substrate 4'
Gas blowing nozzles 51 to 52 located off the top
and 5n-1 to 5n, the first stop valves 71 to 72 and 7n-1 to 7n are closed, and the second stop valves are closed.
Stop valves 81 to 82 and 8n-1 to 8n
Open the gas blowing nozzles 51 to 52 and 5n.
-1 to 5n, a gas containing no growth material, such as hydrogen, is introduced at a flow rate approximately equal to that of the gas containing the material introduced from these nozzles in the case of the first growth substrate 4, and An epitaxial layer of uniform thickness is grown on the growth substrate 4'.

In the above growth, each gas blowing nozzle 5
The gas flow rate discharged from 1 to 5n and the raw material concentration of the gas containing the growth raw material are approximately constant. Therefore, according to the vapor phase growth apparatus of the present invention, it is sufficient to flow a gas containing a growth material approximately proportional to the size of the substrate to be grown, and the amount of material gas can be reduced.

[0013] Furthermore, even when the growth substrate is small, the reaction products are not deposited on the susceptor exposed around the growth substrate, which prevents the occurrence of growth defects due to exfoliated and scattered particles of the reaction products. is avoided.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to a schematic longitudinal sectional view of the main parts of the apparatus shown in FIG.

The vertical MOVPE apparatus used in this example has a reaction vessel (reaction tube) 1 having a vacuum exhaust port 11 at the bottom.
For example, five gas blowing nozzles 51 to 55 are sequentially arranged in a row on the same plane on the upper part of the reaction vessel 12, and the growth substrate 4 is supported in the reaction vessel 12 so as to face parallel to the nozzle surface. A susceptor 3 is disposed supported by a rotation shaft 13, and the gas blowing nozzle 51
~55 are gas flow rate control means 61 ~65, respectively.
, first pipes 91 to 95 and first stop valves 71 to 75 in order to the supply pipe 1 for the gas containing the growth raw material, and each of the first pipes 91 to 95 is connected to a second pipe as a bypass. It has a structure in which pipes 101 to 105 are connected, and these second pipes 101 to 105 are connected to a gas supply pipe 2 that does not contain a growth material via second stop valves 81 to 85, respectively.

Using this device, for example, indium phosphorus [In
When epitaxially growing P], 20% phosphine [PH3] (hydrogen-based) is used as the raw material gas.
and trimethylindium [(CH3)3In] (sublimation vessel temperature 20°C), 20% PH3 1000 ccm
A first gas containing a growth raw material was prepared by mixing 150 ccm of (CH3)3In with 8850 ccm of hydrogen [H2] as a carrier gas. Moreover, H2 gas was used as the second gas that does not contain the growth material.

[0017] Gas blowing nozzles 51 to 55
When epitaxially forming an InP layer on a growth substrate 4 made of, for example, InP and having a diameter of, for example, 3 inches, the first stop valve 71 to
75, and open the second stop valves 81 to 85.
are all closed and controlled by the gas flow rate control means 61 to 65, for example, the flow rate of the gas blowing nozzles 51 and 55 is set to 2240 ccm, and the flow rate of the gas blowing nozzles 52 and 54 is set to 19 ccm.
The flow rates of 00 ccm and 53 are adjusted to 1720 ccm, respectively, and all gas blowing nozzles 51 to 55 are
The first gas is introduced from
A 1 μm thick InP layer was grown at 630° C. while maintaining the temperature at 6 Torr and rotating the susceptor at 50 to 60 rpm.

In this growth, the distribution of the film thickness of the epitaxial layer in the region excluding the peripheral 3 mm of the 3-inch substrate 4 was within ±2.5%. Next, on a growth substrate made of InP having a diameter of 2 inches, gas blowing nozzles 52, 53, and 54 located on this substrate are injected with the same flow rate as in the case of a 3-inch substrate, that is, nozzles 52 and 54.
The first of 1900ccm in 53 and 1720ccm in 53
Flow the gas, close the first stop valves 71 and 75, open the second stop valves 81 and 85,
From the gas blowing nozzles 51 and 55, the flow rate of the gas containing the raw material in the case of growth on a 3-inch substrate is 2240 ccm.
A gas that does not contain a growth material at approximately the same flow rate as hydrogen [
H2] was introduced, and at the same gas pressure, rotation speed, and temperature in the container as in the case of the 3-inch substrate, a 1-μm-thick InP
Epitaxial growth of the layers was performed.

Also in this growth, a film thickness distribution within ±2.5% was obtained in the region excluding the peripheral 3 mm of the 2-inch substrate. In addition, in this growth, the gas introduced from the gas blowing nozzle located on the susceptor exposed outside the growth substrate is a gas that does not contain the growth material, such as hydrogen [H2]. The reaction product was not deposited thickly, and therefore, there were almost no defects in the epitaxial layer due to flaking and scattered particles of the reaction product.

As is clear from the above examples, in the MOVPE apparatus according to the present invention, substrates of different sizes can be grown with uniform thickness and fewer defects without replacing the growth jig. can grow epitaxial layers,
Additionally, the amount of gas containing the growth material can be correspondingly reduced when growing on smaller substrates.

The structure of the present invention is of course applicable not only to the MOVPE apparatus but also to other vertical vapor phase growth apparatuses. Further, nitrogen, inert gas, etc. are also used as the gas that does not contain the growth raw material.

[0022]

[Effects of the Invention] As explained above, according to the present invention, an epitaxial layer of uniform thickness can be grown on a growth substrate of any size without replacing the growth jig. , throughput is improved without causing equipment downtime.

Furthermore, since the flow rate of the gas containing the growth material is determined approximately in proportion to the size of the substrate to be grown, the uniformity of the film thickness can be improved while eliminating the use of excess materials and reducing manufacturing costs. Excellent epitaxial growth becomes possible.

[Brief explanation of the drawing]

[Figure 1] Schematic diagram for explaining the principle of the present invention

[Fig. 2] A schematic longitudinal cross-sectional view of an embodiment of the present invention

[Figure 3] Schematic longitudinal cross-section of a conventional vertical MOVPE device

[Explanation of symbols]

1 Supply pipe for gas containing growth raw material (first gas) 2
Supply pipe 3 for gas (second gas) that does not contain growth raw materials
Susceptor 4 First growth substrate 4' Second growth substrate 51 ~ 5n Gas blowing nozzle 61 ~ 6n Gas flow rate control means 71 ~ 7n First stop valve 81 ~ 8n
Second stop valve 91 - 9n First piping 101 - 10n Second piping 11 Vacuum exhaust port 12 Reaction container (reaction tube) 13 Rotating shaft

Claims (1)

[Claims] 1. A vapor phase growth apparatus having a plurality of gas outlets for introducing gas into a reaction vessel from one direction, and in which a substrate to be grown is disposed facing the gas outlets, which contains a growth raw material. A vapor phase growth apparatus characterized in that a first gas and a second gas that does not contain a growth material are introduced into a reaction vessel by being switched independently for each gas outlet.