JPH0415913A - Organicmetal vapor growth method and susceptor therein used - Google Patents

Abstract

PURPOSE:To increase the number of vapor growth of organicmetal remarkably to reduce the manufacturing cost and to increase an yield of the product by using such a susceptor that has the surface roughness of silicon carbide installed on its surface within the specific range when developing a III-V compound semiconductor thin film on a substrate by the pyrolysis of organometallic gas and a hydride of the V group. CONSTITUTION:A susceptor 1 is made of carbon 2 and SiC 3 which is installed on the surface. The surface roughness of SiC is ranged from 10 to 100mum. In the case that the surface roughness of SiC is below 10mum, a contact area between a GaAs crystal developed on the surface of SiC and SiC is small, thus getting a bad adhesion. In the case that the surface roughness of SiC is over 100mum, the adhesion between a substrate and the susceptor gets bad, with the result of a bad heat transmission to the substrate. The more desirable range of the surface roughness of SiC is from 20 to 30mum.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention is directed to metal organic vapor phase epitaxy (Metal Organ Vapor Phase Epitaxy).
cVapor Phase Epitaxy, hereinafter referred to as MO
This paper relates to an improvement of the VPE method and the susceptor used therefor.

(Prior Art) A currently used MOVPH reactor has a barrel-type structure as shown in FIG. In the figure, reference numeral 4 denotes a reactor, which has a gas inlet 5 at its upper end and a gas inlet 6 at its lower side wall. Additionally, an exhaust lower is provided on the central side wall. A shaft 8 is inserted from the center of the lower end of this reactor 4 to the upper part of the reactor 4,
A susceptor 9 is provided at this upper end. 10 is a substrate attached to this susceptor 9. An RF coil 11 is provided on the outer periphery of the reactor 4 in a portion where the susceptor 9 is located.
is installed.

Gallium arsenide using the above reactor An explanation will be given using the growth of (GaAs) as an example.

The GaAs substrate is placed on the substrate 9, and the R
It is heated by the F coil 11 to a predetermined temperature (usually 600 to 750°C) by high frequency induction. Trimethyl gallium (TMGa) and arsine (AsH*
) is introduced into the reactor 4 through the gas inlet 5.6 together with hydrogen gas as a carrier gas, causing a thermal decomposition reaction in the vicinity of the GaAs substrate, thereby growing GaAs on the QaAs substrate.

After that, it is exhausted from the exhaust lower. At this time, the susceptor is rotated in order to average out the differences between the wafers.

Note that high purity carbon is used for the susceptor. Further, in order to prevent degassing from carbon, a coating of 100 to 200 μm of SiC is applied.

(Problems to be Solved by the Invention) In the growth of GaAS described above, GaAs grows not only on the substrate but also on the susceptor. Ga grown on the susceptor
Depending on the susceptor, As may be peeled off to a thickness of around 100 μm, or may be peeled off to a thickness of around 10 μm.

When the GaAs grown on the susceptor peels off, its fragments fall onto the GaAs substrate, causing surface defects. 4
If peeling starts after about 0 growths, this will not cause a decrease in productivity even if this is used as a guideline for maintenance, but if peeling starts after about 4 growths, it will cause problems in productivity. .

In addition, when the GaAs on the susceptor peels off, the purge efficiency of air that has entered the gap between the lifted GaAs film and the susceptor deteriorates, and the oxygen released from there causes the electricity Causes poor characteristics and surface defects.

The present invention has been made in view of the problems of the prior art described above, and has been made for the purpose of providing an organometallic vapor phase epitaxy method in which peeling of GaAs crystals is less likely to occur, and a susceptor for use therein.

(Means for Solving the Problems) The present inventors conducted various studies in view of the problems of the prior art described above, and found that the peelability of GaAs crystals from a susceptor differs depending on the roughness of silicon carbide (SiC). Based on this knowledge, the present invention was completed.

That is, the present invention provides (1) when growing a thin film of an m-v group compound semiconductor on a substrate by a thermal decomposition reaction of an organometallic gas and a group V hydride, the surface roughness of silicon carbide on the surface is reduced to 10-100 μm. (2) A susceptor for organometallic vapor phase epitaxy characterized in that the surface roughness of silicon carbide on the surface of the susceptor is 10 to 100 μ-. This is what we provide.

The present invention will be explained in more detail below with reference to the drawings. 1st
The figure is a perspective view showing an example of a susceptor used in the present invention, and FIG. 2 is a partially enlarged cross-sectional view showing its cross-sectional shape.

In the figure, 1 is a susceptor, which is made of carbon 2 and SiC 3 provided on its surface. In the present invention, the surface roughness of SiC is set to 10 to 100 μm. This is because when the SiC surface roughness is less than 10 μm, the contact area between the GaAS crystal grown on the SiC surface and SiC is small and the adhesion is poor. Furthermore, if the surface roughness of SiC exceeds 1100a, the adhesion between the substrate and susceptor becomes poor (this is thought to result in poor heat transfer to the substrate).S
The surface roughness of iC is more preferably 20 to 30 μm.

Note that the above-mentioned surface roughness is defined as the difference between the maximum value and the minimum value of the unevenness of the SiC surface measured by a step measuring device.

Further, the formation of SiC on carbon is performed, for example, by a CVD method, and the film thickness of SiC is preferably 100 to 2001 J.
, II+.

Note that the susceptor of the present invention is not only made of GaAs but also, for example, Aj
2GaAs, InP, InGaAs, InGaP, I
It can be used for organic metal vapor phase growth of nGaAsP and the like.

Further, the shape is not limited to that shown in FIG. 1; any conventional shape can be used.

The organometallic vapor phase epitaxy method of the present invention can be performed under all the same conditions as the conventional method except for using a specific susceptor as described above, and is capable of depositing an m-V group compound semiconductor thin film on a substrate. Applicable to all growing methods.

(Example) Next, the present invention will be explained in more detail based on examples.

In the susceptor shown in Figure 1 above, the surface roughness of SiC is 2.
0 to 30 μm and 5 μm or 120 μm shoes were installed in the apparatus shown in Figure 3, and a GaAs substrate (2 inches in diameter) was attached to it using trimethyl gallium and arsine as source gases and hydrogen gas as carrier gas. GaAs was grown under the following conditions.

(Gas flow rate) Total flow rate 100β/minTM
Ga 10cc/m1nAsH*
300cc/m1n (temperature)
650° C. (Growth film thickness) 2.5 to 3.0 μm/Table 1 shows the results obtained from the above test.

Although growth was performed five times using No. 12 susceptor, no peeling of GaAs on the susceptor was observed;
The experiment was stopped because the surface condition of the As substrate deteriorated, which was thought to be caused by the temperature drop. As a result, the number of times of organic metal vapor phase growth can be significantly increased compared to the conventional method, and it is possible to reduce manufacturing costs and improve product yield.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of a susceptor of the present invention, FIG. 2 is an enlarged partial cross-sectional view thereof, and FIG. 3 is a cross-sectional view of a metal organic vapor phase growth apparatus used in the present invention. 1...Susceptor, 2...Carbon, 3...5iC
14...9 reactor, 5.6...gas inlet, 7...
Exhaust port 8...shaft, 9...susceptor, 10...
・Substrate, 11...RF coil Fig. 1 Carbon IC

Claims (2)

[Claims] (1) On the substrate due to the thermal decomposition reaction of organometallic compound gas
A metal organic vapor phase epitaxy method characterized in that a susceptor having a silicon carbide surface with a surface roughness of 10 to 100 μm is used for growing a thin film of a III-V compound semiconductor. (2) The surface roughness of silicon carbide on the susceptor surface is 10 to 1
A susceptor for organic metal vapor phase epitaxy, characterized in that the thickness is 00 μm.