JPS63228716A - Vapor growth equipment - Google Patents

Abstract

PURPOSE:To form easily and surely a compound semiconductor layer with a desired composition ratio, by providing a source region separated from a growth region by a check valve with a purge gas supplying pipe and an exhaust pipe. CONSTITUTION:For example, in the case of forming a gallium and arsenic layer, gallium is mounted on a source stand 13 in the source region 11 of a reaction tube 1, and arsenic trichloride from a reaction gas supplying pipe 2 and hydrogen from a bypass tube 4 are supplied. The inside pressure of the region 11 is higher than that of a growth region 12, and so a check valve 5 separating the regions 11 and 12 opens to supply gallium and arsenic to the region 12. Thus, gallium and arsenic are grown in a substrate on a retainer 14. When arsenic reaches a supersaturation state and the supplying tube 2 is closed, the inside pressure of the region 11 decreases and the check valve 5 closes. As the reaction gas is not supplied to the region 12, the growth of a semiconductor stops, and a transition layer and the like are not formed. On the other hand, purge gas of low pressure is supplied through a purge gas supplying pipe 6, and the residual gas in the region 11 is discharged through an exhaust pipe 7. By this constitution, a compound semiconductor layer with a desired composition ratio can be easily and surely formed.

Description

[Detailed description of the invention] 〔overview〕 This is an improvement to the vapor phase growth apparatus.

The reaction tube is divided into a source region and a growth region by a check valve, and the source region is further provided with a purge gas supply pipe for supplying purge gas to the source region and a purge gas discharge pipe for discharging purge gas from the source region. This is a vapor phase growth apparatus with additional features.

[Industrial application field]

The present invention relates to an improvement in a vapor phase growth apparatus.

In particular, the present invention relates to an improvement that makes it possible to form a good Peter junction without generating a transition layer when switching reaction gases to form a Peter junction.

[Conventional technology]

2. Description of the Related Art In manufacturing methods for semiconductor devices, vapor phase growth is widely used to form semiconductor epitaxial layers, various insulator layers, etc., and a vapor growth apparatus is essential for implementing this vapor growth method.

A vapor phase growth apparatus according to the prior art will be explained with reference to FIG.

In the figure, 1 is a quartz reaction tube, and a source region 11
In FIG. 0, which includes a growth region 12 and a source region 11, the right side is the source region 11, and the left side is the growth region 12. A reactive gas supply pipe 2 is provided in the source region 11, and a reactive gas is supplied in the direction of arrow A. 3 is a gas exhaust pipe, which exhausts gas from the growth region 12. A bypass pipe 4 supplies carrier gas to the growth region 12.

To form, for example, a gallium arsenide layer using this vapor phase growth apparatus, gallium is placed on the source stage 13, arsenic trichloride is supplied from the reaction gas supply pipe 2, and on the other hand, the bypass pipe 4
Hydrogen etc. will be supplied from Chlorine gas generated by decomposition of gallium and arsenic trichloride is discharged from the gas exhaust pipe 3.

As this reaction progresses, gallium and arsenic are supplied to the growth region 12 in a desired atomic ratio. At this point, the substrate support 14 carries the gallium arsenide substrate and brings it to the growth region, depositing a gallium arsenide layer thereon.

After a while after this growth reaction progresses, the source surface becomes covered with gallium arsenide, resulting in a source supersaturation state, and the growth region is no longer supplied with gallium and arsenic in the desired atomic ratio, so arsenic trichloride It is necessary to take appropriate control measures such as temporarily stopping the supply of source to release the source supersaturation state.

[Problem that the invention seeks to solve]

In the vapor phase growth method using the vapor phase growth apparatus according to the prior art mentioned above, as mentioned above, control is performed so that the substance to be deposited is supplied to the growth region with a desired number of atoms. However, for a while after switching between the growth process and the supersaturation process described above, it is difficult to avoid the influence of residual gas (in the above example, gas containing excessive arsenic trichloride).
Disadvantages such as the formation of a transition layer are inevitable.

The purpose of the present invention is to provide a vapor phase growth apparatus that does not have such drawbacks, and specifically, it is an object of the present invention to provide a vapor phase growth apparatus that can easily and reliably form a compound semiconductor layer having a desired composition ratio accurately. An object of the present invention is to provide a phase growth device.

[Means for solving problems]

The means taken by the present invention to achieve the above object is to divide the reaction tube (1) of the vapor phase growth apparatus into a source region (11) and a growth region (12) using a reverse valve (5). Furthermore, the source region (11) is provided with a purge gas supply pipe (6) for supplying purge gas to the source region (11) and a purge gas discharge pipe (7) for discharging purge gas from the source region (11). It's in the addition.

[Effect]

The cause of the above drawback is that undesired residual gas remains in the growth region for some time after switching between the growth process and the supersaturation process. Therefore, the vapor phase growth apparatus according to the present invention has a structure that makes it possible to stop supplying the residual gas to the r&long region at the same time as switching between the growth process and the supersaturation process. .

〔Example〕

DESCRIPTION OF THE PREFERRED EMBODIMENTS A vapor phase growth apparatus according to an embodiment of the present invention will be further described below with reference to the drawings.

In the diagram shown in FIG. 1, l is a quartz reaction tube, and the source region 11
In FIG. 0, which includes a growth region 12 and a source region 11, the right side is the source region 11, and the left side is the growth region 12. A reactive gas supply pipe 2 is provided in the source region 11, and a reactive gas is supplied in the direction of arrow A. 3 is a gas exhaust pipe, which exhausts gas from the growth region 12. A bypass pipe 4 supplies carrier gas to the growth region 12.

5 is a check valve according to the gist of the present invention, and the source region 11
When the internal pressure of is higher than the internal pressure of the growth region 12, it is opened,
Gas is supplied from the source region 11 to the growth region 12,
It has a function of closing when the internal pressure of the growth region 12 is higher than that of the source region 11 and prohibiting gas from being supplied from the source region 11 to the growth region 12. In this example, the internal pressure of the source region 11 is closed. 6 is a purge gas supply pipe, and 7 is a purge gas discharge pipe.

To form, for example, a gallium arsenide layer using the vapor phase growth apparatus having the above structure, gallium is placed on the source stage 13, arsenic trichloride is supplied from the reaction gas supply pipe 2, and on the other hand, arsenic trichloride is supplied from the bypass pipe 4. Hydrogen is supplied, gallium and arsenic trichloride are reacted, and the surface of the gallium source is converted into a gallium arsenide layer.

At this point, the check valve 5 is open, and the gallium and arsenic generated by the above reaction are supplied to the growth region 12. Then, when the substrate is brought to the growth region 12, gallium arsenide grows.

When the process progresses and arsenic supersaturation is reached, the reaction gas supply pipe 2 is closed to stop the supply of the reaction gas (arsenic trichloride), and the purge gas discharge pipe 7 is opened to discharge residual gas containing excessive arsenic. This reduces the internal pressure of the source region 11. Then, the check valve 5 closes, and the growth region 12 is no longer supplied with anything other than the carrier gas, which is also supplied by the bypass pipe 4.

Semiconductor growth on the substrate stops. It is clear that no transition layer or the like is formed in this state.

Therefore, a purge gas is supplied at low pressure from the purge gas supply pipe 6 to completely exhaust the residual gas from the source region 11.

When the residual gas is completely exhausted from the source region 11, the purge gas supply pipe 6 is closed, the purge gas discharge pipe 7 is further closed, and the supply of arsenic trichloride is started from the reaction gas supply pipe 2, and the growth process is restarted.

Even during this process switching, no residual gas is supplied to the growth region, so no transition layer or the like is formed.

The mechanism of the check valve 5 described above will be explained in some detail.

Reference numeral 51 in FIG. 2 is a flow mechanism, in which a funnel-shaped lower stopper 52 is provided, and a sphere 53 is placed so as to block this lower stopper 52. When the internal pressure of the source region 11 is high, the sphere 53 floats along the funnel-shaped stopper 52 and opens the flow path, but when the internal pressure of the source region 11 becomes low, the sphere 53 descends and blocks the flow path. 54 is an upper stopper, which prevents the sphere 53 from flying into the reaction area 12.

〔Effect of the invention〕

As explained above, when vapor phase growth is performed using the vapor phase growth apparatus according to the present invention, residual gas is not supplied to the growth region, so a transition layer etc. is not formed, and the desired composition ratio can be maintained. It is possible to easily form a compound semiconductor layer or the like having an accurate shape.

[Brief explanation of drawings]

FIG. 1 is a structural diagram of a vapor phase growth apparatus according to an embodiment of the present invention. FIG. 2 is a structural diagram of a check valve used in a vapor phase growth apparatus according to an embodiment of the present invention. FIG. 3 is a structural diagram of a vapor phase growth apparatus according to the prior art. DESCRIPTION OF SYMBOLS 1... Reaction tube, 11-... Source region, 12... Growth region, 2... Reaction gas supply pipe, 311... Gas discharge pipe, 4... Bypass pipe, 5... Back check Valve, 511. Flow mechanism, 52.. Lower stopper, 53.. Sphere, 54. Upper stopper, 6.. Fist purge gas supply pipe, 7.. Purge gas discharge pipe.

Claims (1)

Claims: A reaction tube (1) having a source region (11) and a growth region (12);
1), a reaction gas supply pipe (2) that supplies the reaction gas to the growth region (12), and a gas exhaust pipe (3) that discharges the gas from the growth region (12).
and a bypass pipe (4) for supplying a carrier gas to the growth region (12), the check valve (5) separating the source region (11) and the growth region (12). provided, said source region (11)
A vapor phase growth apparatus characterized in that a purge gas supply pipe (6) for supplying purge gas to the source region (11) and a purge gas discharge pipe (7) for discharging the purge gas from the source region (11) are provided.