JPS6360523A - Oxygen removing device - Google Patents

Abstract

PURPOSE:To remove small amount of remaining moisture and oxygen by mounting a material having a shape which can pass gas in contact with the surface, being reactive sensitively with the oxygen and easily oxidized in a gas passage. CONSTITUTION:An aluminum structure having many through holes 3 of about 1mm in diameter of columnar high purity aluminum 2 is disposed at a point A, small amounts of oxygen, hydrogen gas including moisture, AsH3 gas, TMG gas, TMA gas introduced from group III element gas supply port 16 and group V element gas supply port 20 are supplied through an oxygen removing unit mounted in a suitable temperature region in a reaction tube onto a substrate 24. In this case, when the gases pass the unit, the small amounts of oxygen and moisture contained in the gases react with high purity aluminum to be removed from the gases as oxides. When the unit is mounted in the tube 21, arbitrary temperature region near the room temperature from the temperature of the substrate 24 can be selected in the tube 21. Thus, the small amounts of oxygen and moisture can be extremely simply removed.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to the purification of various gases used during various processes including semiconductor manufacturing processes.

Conventional technology In the manufacturing process of semiconductor devices such as various compounds such as SiF, impurity doping gases are used.

A wide variety of gases are used, including epitaxial growth gases, dry etching gases, and atmosphere control gases. These gases are sufficiently purified in advance and generally have a high purity of 5-6 ninθ, especially when extreme considerations regarding oxygen are not required.
There is no problem with the raw material gas itself, but oxygen, moisture, etc. adsorbed in the gas piping system and inside the cylinder still remain.
For example, A7! is well known as an important material for semiconductor lasers! In the crystal growth process of GaAs etc.
It is well known that the presence of residual oxygen or moisture seriously affects device characteristics.

The conventional method will be explained below by taking as an example the MOCVD epitaxial growth of AdGaAs/GaAs, which is widely used in the manufacture of semiconductor lasers.

2nd figure bam 7! GaAs/GaAs (7) MOC
FIG. 1 is a schematic diagram of the basic part of a V D epitaxial growth apparatus. A portion of the hydrogen gas supplied from the hydrogen cylinder 11 is flow-controlled by the mass flow meter 12 and has a constant diameter.
Ga and A7! Trimethylgallium (T
MG) and trimethylaluminum (TMA) bubbling gas: TMG cylinder 13, TMA cylinder 14
The hydrogen gas containing TMG and TM steam is combined with the hydrogen gas that has passed through the gas pipe 16 at points A and 8 in the figure, respectively, and is led to the source gas inlet 16. On the other hand, the raw material for the person S is arsine (MusH,) diluted into hydrogen gas, which comes out of the cylinder 17, and after the supply amount is controlled by the mass flow meter 18, the gas pipe 1
After joining with the hydrogen gas coming through 9 at point 0, it is led to the V raw gas inlet 20. The TMG thus arrived at the reaction tube 21 together with the carrier gas (hydrogen gas).

TMA, AsH3 gas is mutually mixed inside the reaction tube 21 while the GaAS substrate 2 placed on the susceptor 23 heated by the high frequency coil 22 is heated.
A thermal decomposition reaction occurs on the GaAs substrate 24, and AlxGa, -xAsf having a predetermined mixing ratio xl is deposited on the GaAs substrate 24. A7! The remaining gases that do not contribute to the deposition of xGa and -xAs are exhausted to the outside through the exhaust port 25. The deposition of GaAs can be easily performed by stopping the supply of bubbling hydrogen gas to the TMA cylinder 14 using the valve 26.

Problems to be Solved by the Invention In the above-mentioned systems, gases with sufficient purity are normally used as each raw material gas and hydrogen gas, but for example, the inner wall of the cylinder used, is moisture that adheres to the inner walls of gas pipes.

It is extremely difficult to completely remove oxygen and the like, and the main purpose of the present invention is to provide a means for removing such trace amounts of residual moisture and oxygen.

Means for Solving the Problems In order to solve the above-mentioned problems, the present invention provides a method of forming oxides by sensitively reacting with oxygen at a point in a suitable temperature range between the susceptor and the gas inlet in the reaction tube. The above object is achieved by installing a structure for removing oxygen that has a structure in which the contact surface with the passing gas is made of a material such as AM, for example, and has a hard surface.

Effect of the present invention With the above configuration, when various supply gases pass through while contacting the structure made of Aβ, trace amounts of oxygen and moisture contained in the supply gas react with the above-mentioned human body and cause the two people to react. 7! Jucho0□→A l 203 2 people β+3H20−+Ag2O3+3H2, and oxygen and moisture are removed.

Embodiment FIG. 1 shows an embodiment of the Ad structure (oxygen removal device) 1 of the present invention, (&) is a cylindrical high-purity aluminum 2 with many through holes 3 of about 1Uφ, (' b) (i Quartz tube 4
A high-purity aluminum grinding piece 5 is placed inside, and the front and back are sealed with quartz phthalo having many through holes of about 1uφ.
(C) uses a meshure made of high-purity aluminum, and in the same way as described in the conventional example in which the oxygen removal device shown in Figure 1 is placed at the entry point in Figure 2, the raw gas supply shown in Figure 2 is used. Hydrogen gas, AsH3 gas, TMG containing trace amounts of oxygen, moisture, etc. introduced from the port 16 and the V raw gas supply port 20
gas.

A gas such as TM gas is supplied onto the surface of the substrate 24 through the entire oxygen removal device 1 installed in a suitable temperature region in the reaction tube. At this time, when the gas passes through the oxygen removal device 1, trace amounts of oxygen and moisture contained in the gas react with high-purity aluminum and are released as oxides in the gas, as described in the section of the operation above. It will be removed.

In normal cases, the oxygen removal device 1 is preferably installed in the reaction tube 21 at a temperature of 3°C or lower in order to prevent the decomposition of the gases such as AsH, TMG, TMA, etc. When the oxygen removal device 1 is installed inside the reaction tube 21 as shown in FIG. 2, it is generally possible to select any temperature range inside the reaction tube 21 from the temperature of the substrate 24 to around room temperature. Therefore, the oxygen removal device may be installed in an appropriate temperature range depending on the gas used. By installing the oxygen removing device 1 of the present invention between the susceptor 23 in the reaction tube 21 and the gas inlet 16°2o as shown in FIG. 2, trace amounts of oxygen and moisture in the supplied gas can of course be removed. However, there is also the effect of gas mixing, that is, the various gases supplied from the gas inlet 16.20 encounter resistance at the front of the oxygen removal device 1, and the resistance between the oxygen removal device 1 and the gas inlet 16.20 increases. The space between is 1
Acts as a gas mixer for seeds. Then, the gas that has passed through the oxygen removal device 1 is mixed and distributed in a - manner,
In addition, since the gas outlets of the oxygen removing device 1 are uniformly distributed with respect to the cross section of the reaction tube 21, it also has the advantage of easily forming a clean laminar flow.

Effects of the Invention By using the oxygen removal device of the present invention, trace amounts of oxygen and moisture contained in gas, or trace amounts of oxygen and moisture deposited on the inner walls of cylinders and gas supply pipes, etc., and carried along with the gas flow can be removed. can be easily and conveniently removed using an extremely simple device.

[Brief explanation of drawings]

FIG. 1 is a block diagram of an oxygen removal apparatus according to the present invention, and FIG. 2 is a block diagram of an MOCVD epitaxial growth apparatus. 1...Oxygen removal device, 2...High purity aluminum, 3...Through hole, 4...Quartz tube,
5. Old: High-purity aluminum ground piece, 6”: Quartz lid, 7: High-purity aluminum mesh. Name of agent: Patent attorney Toshio Nakao and 1 other person 5P
J1 Figure 11 - Water turbine cylinder 12 - Mass flow meter 13 - T n Cr cylinder 14 - - TnA cylinder 15 - Gas tube / 6 - M group gas 4 inlet 1'l - - To A s Hs cylinder 18 - -Mass flow meter 19-Gas sound 2θ-V group gas 4 inlet tube Figure 2 21-Reaction tube 22-, % liquid coil 23- Susceptor? 4---6I2AS Kishu? 5---Hai Exit

Claims (4)

[Claims] (1) In various process equipment such as semiconductors that use gas, the gas passages are made of materials that have a shape that allows gas to pass through while in contact with the surface, that react sensitively to oxygen, and that are easily oxidized. An oxygen removal device characterized by being installed. (2) The oxygen removal device according to claim 1, wherein a large number of thin through holes are provided along the axial direction of the high-purity aluminum cylinder. (3) The oxygen removal device according to claim 1, wherein both ends of the quartz tube are sealed with quartz plates having a large number of pores, and the inside of the quartz tube is filled with ground pieces of high-purity aluminum. (4) The oxygen removal device according to claim 1, characterized in that at least one mesh made of high-purity aluminum is stacked and installed perpendicular to the gas flow.