JPS6333811A - Vopor growth method - Google Patents

Abstract

PURPOSE:To prevent a reactive substance from adhering to a flange thereby to obtain a hetero boundary or a boundary of a P-N junction extremely abruptly with high reproducibility by providing a gas flow reflecting plate at the downstream position of a susceptor to reflect reactive gas passed over the susceptor on the reflecting plate to flow to an outlet. CONSTITUTION:When reactive gas is fed into a crystal growth chamber to form a thin crystal film on a substrate 9 on a susceptor 8 placed in the chamber, a gas-flow reflecting plate 11 is mounted at the downstream position of the susceptor 8, and the gas passed over the susceptor 8 is fed by the plate 11 to an outlet 10. With this construction, an apprehension of deposition an adhesive on an 0-ring 5 attached to a flange 5 is eliminated to always hold a hermetical sealability. Since the gas is further reflected in a direction different from a direction of feeding the gas by the plate 11, the gas is not returned toward the susceptor 8 to obtain a hetero boundary and a boundary of a P-N junction extremely abruptly with high reproducibility.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a vapor phase growth method used for crystal growth of compound semiconductors etc. on a substrate. Vapor phase epitaxial growth of group compound semiconductors, especially metal organic vapor phase epitaxy (MOV)
PE:'Metal Organic Vap
orPhaseEpieaxy ) is uniform over a large area.

It has attracted attention due to its ease of mass production, controllability of film thickness and composition, and active research and development is being carried out in various places.

Conventionally, an apparatus used for this type of vapor phase growth method was as shown in FIG. 1 is the inlet and reactant gas, for example Gλ
For the growth of As, trimethylgallium TMG ((CH
3) 5Ga) and arsine ASH3 and carrier gas l
(This is the inlet of z. 2 is the quartz furnace core tube (chamber), 3
4 is an O-ring, 4 is a fixing base for fixing a quartz furnace core tube, 5 is an O-ring attached to a flange 6, such as a pyton, 7 is a susceptor support rod, 8 is a susceptor, 9 is, for example, a Ga-me S substrate, 10 is an exhaust port. The crystal growth chamber consists of a quartz furnace core tube 2 and a fixed table 4. The substrate 9 is connected to the susceptor 8 by, for example, a high frequency coil provided outside the crystal growth chamber.
is heated to a desired temperature by heating it to a predetermined temperature. When the reaction gas g1 is introduced from the inlet 1 and passes through the substrate heated to a desired temperature, a part of it contributes to crystal growth and reaches the substrate 9, but the remaining part is exhausted from the 2 exhaust ports 10. 0 Problems to be Solved by the Invention However, in the method using the above-mentioned device, a part of the reaction gas that has passed over the substrate 9 reaches the flange 6,
The reactant adheres to the flange e. When the susceptor 8 is moved into the chamber to take out the substrate after the crystal growth is completed, the reactant deposited on the flange 6 falls into the chamber and contaminates the chamber. In addition, if the reactant adheres to the O-ring, it not only causes poor airtightness and a decrease in crystallinity, but also poses a safety problem.Furthermore, some of the reactant gas that has passed over the substrate 9 is transferred to the flange 6. After colliding with the susceptor, a part of it is exhausted through the exhaust port 10, and the rest flows toward the susceptor 8 again and may reach the substrate surface. There was a problem that a suitable interface could not be obtained. The flow of this reaction gas is also schematically shown in FIG.

Means for Solving the Problems As a means for solving the above-mentioned problems, the present invention includes a gas flow reflection plate located downstream of the susceptor, so that the reaction gas that has passed over the susceptor is reflected by the gas flow reflection plate. It is designed so that it flows into the exhaust port.

The effect of this technical means is as follows.The reaction gas that has passed over the susceptor is reflected in the direction of the exhaust port by the gas flow reflector provided upstream of the flange, so that the reactant is present at the flange. No more sticking. Accordingly, there is no concern that deposits will accumulate on the O-ring attached to the flange, and airtightness can be maintained at all times. Furthermore, since the reactant gas is reflected in a direction different from the direction in which it was sent by the gas flow reflector, the reactant gas will not return toward the susceptor again, and the hetero interface or pn junction interface will be extremely steep. Good reproducibility can be obtained.

EXAMPLE A specific example using the vapor phase growth method according to the present invention is shown in FIG. A removable gas flow reflection plate 11 is provided on the susceptor support frame, and an exhaust port 10 is provided near the reflection plate 11 in the reflection direction.

Further, the size of the gas flow reflection plate 11 is such that it touches the crystal growth chamber or is smaller than that, and is designed so that there is no problem in its movement. The reaction gas g2 is reflected by the reflection plate 11 and discharged from the exhaust port 10, and does not reach the vicinity of the flange 6. The reflector 11 is preferably inclined at an angle of at least 10° with respect to the support rod 7, and may be integrated with the rod 7 or may be detachable. Further, the reflecting plate 11 is made of stainless steel or the like.

In order to clarify the effects of the present invention, person 1 (-aAs/GaAs jingle quantum well C3) shown in FIG.
QW) Created a structure. As an organic Ga compound, triethyl Ga ((C2H,,)3Ga)TEG, an organic compound
TrimethylAl((CHs)spersonl)T as a compound
M person, Arsin person sH, was used as V raw gas.

The carrier gas is a high purity hydrogen gas passed through a Pd diffusion film, and the current flow rate is 561/min. The substrate 9 is made of GaAs (100
), and the substrate temperature is 700°C. Growth rate is approximately 1μm
TEG or TEG-)-TM so that it is 1 hr.
Adjust the concentration of 0 and A, gGaAs (7
) Ag (TEG and T so that the D mixed crystal ratio is 0.3
The concentration ratio of M people is also adjusted.

First, A lo, s G 'La, y A 3 layers 22
After growing about 0.2111fi on the substrate 9, GaAs
Approximately 40 layers of layer 23 were grown, and further Al, Ga, As
Layer 24: AdCaAs/GaAs/
A human, deaAs SQW is created. A photoluminescence method was used to evaluate the SQW.

Figure 3 shows the 7 otoluminescence of the grown crystal at room temperature. Beak 1 is photoluminescence from GaAs on the surface, and peaks 2 and 3 are photoluminescence from the GaAs well layer. Because the heterointerface is steep, the light emission due to recombination between the heavy hole and light hole is observed separately.

When we tried the same experiment using a gas flow reflector, we found that the surface morphology was not necessarily good, the light emission due to recombination of heavy holes and light holes was not clearly separated, and the heterointerface was not steep. Ta.

In the embodiment described above, the case where the gas flow reflector is oriented in one direction has been described, but the gas flow is reflected in multiple directions symmetrically around the susceptor support rod, and the same number of exhaust ports as the gas flow reflector are provided. Needless to say, by doing so, the gas can be drained extremely well without impairing the symmetry of the gas flow. Furthermore, in this example, AgG
aAs/(-aAs explained on Twitter, but InGaAs
It can be used for crystal growth of not only P/InP type and AlGaInP/GaAs type but also (7) Illr-V group and TI-VI group compound semiconductors and mixed crystal semiconductors.

Effects of the Invention In the vapor phase growth method of the present invention, the reaction gas that has passed over the susceptor is reflected toward the exhaust port by the gas flow reflection plate and does not reach the flange, so that the reaction material does not adhere to the flange. There is no need to worry about contaminating the O-ring attached to the flange, airtightness is maintained, and safety is no longer compromised. In addition, since the reactive gas is reflected toward the exhaust port by the gas flow reflector and does not return toward the susceptor, heterointerfaces and pn junction interfaces can be obtained very precisely and with good reproducibility. As a result, it has become possible to significantly reduce the cost of devices made from this crystal, which has a very practical effect.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of a vapor phase growth apparatus in an embodiment of the present invention, FIG. 2 is a cross-sectional view of an SQW layer produced using the present invention, FIG. 3 is a characteristic diagram showing photoluminescence of SQW, and FIG. FIG. 4 is a schematic diagram of a conventional vapor phase growth apparatus. 2... Quartz furnace core tube, 5... O-ring, 6... Flange, 7... Susceptor support rod, 8... Susceptor, 11...Gas flow reflector, 1o/mountain...exhaust port.

Claims (5)

[Claims] (1) When introducing a reactive gas into a crystal growth chamber and forming a crystal thin film on a substrate on a susceptor placed in the crystal growth chamber, a gas flow reflecting plate is installed at a position downstream of the susceptor, A vapor phase growth method characterized in that the reaction gas that has passed above is caused to flow to an exhaust port by a reflection plate. (2) The gas flow reflector plate is inclined at least 10 degrees with respect to the susceptor support rod and is either integrated with the susceptor support rod or detachable from the susceptor support rod. Phase growth method. (3) The gas flow reflection plate is inclined, and a gas exhaust port is provided in the direction in which the gas flow is reflected and in the vicinity of the gas flow reflection plate. Vapor phase growth method as described. (4) The size of the gas flow reflection plate is such that it is in contact with or smaller than the inner wall of the crystal growth chamber at the position where the gas flow reflection plate is installed. vapor phase growth method. (5) The vapor phase growth method according to claim 1, wherein the gas flow reflection plate is made of stainless steel.