JPH01176294A - Apparatus for vapor growth - Google Patents

Abstract

PURPOSE:To contrive improvement in operating efficiency of an apparatus, by forming a nozzle for introducing reaction gases in bell jars into a double structure and separately introducing different kinds of gases. CONSTITUTION:A nozzle 11 for introducing reaction gases is formed as a double structure consisting of a nozzle (11b) in the central part and a nozzle (11c) on the outer peripheral side. In the process, a purge gas 101 is made to flow from a jetting port of the nozzle (11b) in the direction of (11b1) and a reaction gas 102 is made to flow from a jetting port of the nozzle (11c) in the direction of (11c1). The interior of a bell jar 2 made of quartz and a bell jar 3 made of stainless steel is replaced with nitrogen gas by opening nitrogen gas valves (V1) and (V3) and hydrogen gas is introduced by closing the valves (V1) and (V3) and simultaneously opening valves (V2) and (V4) to increase the temperature and carry out vapor growth. Thereby the time of gas replacement in the bell jars 2 and 3 is reduced to accelerate growth rate of the product surface. As a result, operating efficiency of the vapor growth apparatus is improved.

Description

Detailed Description of the Invention (Industrial Field of Application) The present invention involves bringing a semiconductor substrate heated to a high temperature into contact with a reactive gas, and causing the semiconductor substrate to absorb a substance contained in the reactive gas, or a reaction between the substance and the substrate. The present invention relates to a vapor phase growth apparatus used to grow a desired substance onto a semiconductor substrate using chemical reactions that occur during the growth process.

[Conventional technology]

FIG. 3 is a sectional view showing an example of such a vapor phase growth apparatus.

In FIG. 3, a quartz bell jar 2 and a stainless steel bell jar 3 are airtightly placed on a base plate 1 via an O-ring 4 and fixed by a stopper 15. A reaction gas introduction nozzle 11 for introducing the reaction gas 10 through the pace plate is provided at the center of the bell jar. Further, a disk-shaped susceptor 6 on which a semiconductor substrate to be processed (hereinafter referred to as a wafer) 5 is mounted is attached to the outer periphery of the nozzle 11, and a coil cover 8 is installed on the lower side of the susceptor 6 to shield reaction gas. A spiral high frequency induction heating coil 7 is attached. In the vapor phase growth apparatus having the above structure, the wafers 5 placed on the susceptor 6 are heated by high-frequency induction, and at the same time, the susceptor 6 is rotated by the motor 9 through the rotating shaft 16 to uniformly heat each wafer 5. On the other hand, during this heating reaction gas 10
is ejected from the nozzle 11 in the direction of the arrow 11a, and the wafer 5
to grow a homogeneous film. The gas ejected from the nozzle's ejection port 11a is discharged from the exhaust pipe 12 to the outside of the bell jar. The coil purge 13 is discharged from the coil discharge port 14.

At this time, the temperature is increased by switching to a carrier gas (hydrogen) with an inert gas such as nitrogen gas before and after the growth, and 5iCLtSiH,t5iH is grown on the surface of the wafer 5 in a vapor phase.
cI! , , SiH, (jl, etc.)
Conventionally, source gas v5, doping gas (6), etching gas (7), nitrogen gas for substitution (nitrogen gas), and carrier gas for vapor phase growth (v2) in the wiring diagram (Fig. 4) were switched and the same nozzle 1 was used.
1 and piping system 10 into the bell jar.

[Problem that the invention seeks to solve]

In such a conventional vapor phase growth apparatus, as long as the same nozzle is used, a lot of time is spent replacing the gas in the upper part of the quartz bell jar, and the source during growth, especially Si)! ,, 5
When growing a single crystal on a wafer by thermal decomposition such as iHCQ1, there is a drawback that if the temperature of the quartz bell jar exceeds the source decomposition temperature, products will adhere to the quartz bell jar, resulting in a reduction in the silicon growth rate on the wafer surface.

Such defects become more noticeable in the gas flow direction (higher flow rate) as the diameter of the susceptor increases, which poses a problem in increasing the size of the device.

An object of the present invention is to provide a vapor phase growth apparatus that can shorten gas replacement, increase growth rate, and improve efficiency.

[Differences between the invention and the prior art]

In contrast to the conventional vapor phase growth nozzle described above, the reaction gas introduction nozzle of the present invention has a dual structure that allows different types of gases to be introduced separately, and has a structure in which the replacement gas and carrier gas are ejected from the upper side. The difference is that only the carrier gas is ejected from the side, and a gas containing the carrier gas and source reaction gas is ejected from the side to cause vapor phase growth on the wafer.

[Means for solving problems]

The present invention is a disk-type susceptor vapor phase growth apparatus characterized in that a reaction gas introduction nozzle installed in a bell jar has a double structure for individually introducing different gases.

(Example〕 An embodiment of the present invention will be described below with reference to the drawings.

In Figure 1, base plate 1, bell jars 2, 3
, susceptor 6, high frequency induction heating coil 7, rotating shaft 16
etc. are the same as the conventional device shown in FIG. As shown in FIG. 1, in the present invention, the reaction gas introduction nozzle 11 introduces two types of gases separately in a process, and has a double pipe structure consisting of a nozzle llb in the center and a nozzle 11c on the outer periphery. The purge gas 101 is opened in the direction 11b from the spout of the nozzle llb, and the reaction gas 102 flows in the direction 1101 from the spout of the upper nozzle 11c.
The nitrogen gas valves Vl and V3 in FIG. 2 are opened, and the nitrogen gas is ejected from the nozzle llb at the center and the nozzle llc at the side of the outer circumference and is discharged from the upper part of the bell jar to the outlet 12 at the lower part. Further, hydrogen gas is supplied to valves V2 and 2 at the same time as valves Vl and V3 are closed. V4
After opening the valve and raising the temperature, the growth reaction gas is introduced from the valve v4 side and ejected in the direction 110 from the outlet on the side surface of the nozzle llc on the outer circumferential side to perform vapor phase growth of the wafer.

At this time, the total flow rate of hydrogen gas is set by the flow rate controller NFC, and the ratio of the gas flow rate at the center to the outer circumference is adjusted using the needle valve NVI to obtain a high efficiency value for the growth rate.

〔Effect of the invention〕

Therefore, according to the present invention, the replacement gas and the carrier gas are ejected from the center and the outer periphery of the nozzle, thereby shortening the gas replacement and spraying the carrier gas from the center of the nozzle to the upper part of the bell jar during the growth reaction, thereby spraying the carrier gas onto the bell jar surface. At the same time, it can suppress the gas including the source gas ejected from the side of the nozzle so that it does not rise, and at the same time use the heat conduction of hydrogen gas to increase cooling efficiency and prevent product adhesion, thereby increasing the growth rate on the wafer surface. . Furthermore, it is possible to obtain efficient growth with respect to the source gas, which has the effect of improving the operating rate of the apparatus.

[Brief explanation of the drawing]

Fig. 1 is a sectional view of a growth furnace showing an embodiment of the present invention, Fig. 2 is a partial diagram of a gas piping system diagram for introducing gas into the nozzle of Fig. 1, and Fig. 3 is a conventional vapor phase growth apparatus. FIG. 4 is a partial diagram of a gas piping system diagram for introducing gas into the nozzle of FIG. 3. 1...Base plate 2...Quartz bell jar 3...Stainless steel bell jar 4...0 ring 5...Wafer 6...Susceptor 7.
...High frequency induction heating coil 8...Coil cover 9
...Motor 10,10. ．． 10□・・
・Reaction gas 11, llb, lie...nozzle 12
...Discharge port 13...Coil purge 14...
Coil discharge port 15... Stopper 16...
・Rotating axis ■1~v4...Valve NVI...
Needle valve NFC...flow control section

Claims (1)

[Claims] (1) A disk-type susceptor vapor phase growth apparatus, characterized in that a reaction gas introduction nozzle installed in a bell jar has a double structure for individually introducing different gases.