JPS60211072A - Gasification apparatus of volatile substance - Google Patents

Abstract

PURPOSE:To perform stably the supply of volatile matter and a carrier gas to a CVD reaction chamber by providing pressure gauges, pressure control valves and check valves respectively to an inlet of the carrier gas and an outlet of the carrier gas and the volatile matter in a gasification vessel of a volatile substance used in the CVD apparatus or the like. CONSTITUTION:A carrier gas is supplied to a gasification vessel incorporated with volatile substance 3 from an inflow port 1 and supplied to a CVD reaction chamber from an outflow port 5 together with the vapor of the volatile substance gasified in the gasification vessel. Pressure gauges 6, 7, pressure control valves 8, 9 and check valves 10, 11 are respectively fitted to a gas inflow port 1 and an outflow port 5. Since the pressure of gas in the gasification vessel can be suitably controlled with both the valves 8, 9, it can be maintained at constant without being affected by the outer pressure. As a result, the amount of the volatile matter to be gasified is decided with only the temp. and the amount of vapor of the volatile matter to be supplied and the carrier gas can be precisely controlled by maintaining the temp. at constant and also the vapor of volatile matter is prevented with the check valves 10, 11 from being flowed out to the outer part from the gas inflow port 1.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to vapor phase epitaxial growth and chemical transport growth (OVD HGhemlaal vapor deposition).
The present invention relates to a device for vaporizing volatile substances used as a raw material gas in such applications as

2. Description of the Related Art Structures of Conventional Examples and Their Problems In recent years, volatile substances have been increasingly used in manufacturing processes for compound semiconductor devices and silicon semiconductor devices.

That is, in the case of vapor phase epitaxial growth of compound semiconductors, such as norlide vapor phase epitaxial growth method, metal organic pyrolysis method (MO (CVD method)), and electrode formation by CVD method, for example, formation of molybdenum electrodes, volatile substances are vaporized. The raw material gas is used as raw material gas.

A conventional volatile substance vaporization container will be explained below.

FIG. 1 shows a conventional volatile substance vaporization container.

1 is a carrier gas inlet, 2 is a carrier gas inlet valve, 3
is a volatile substance, 4 is an outlet valve for carrier gas and vaporized volatile substance, and 6 is an outlet for carrier gas and vaporized volatile substance.

As shown in Figure 1, in the conventional vaporization container for volatile substances,
A structure in which the pressure of the carrier gas supply source is directly applied to the inlet side of the carrier gas, and the pressure in a reaction chamber such as a crystal growth chamber or CVD chamber is directly applied to the outlet side of the carrier gas and vaporized volatile substances. It became.

However, in the above structure, the pressure inside the vaporization vessel is not the same as the pressure inside the reaction chamber, and therefore the amount of volatile substances vaporized is greatly influenced by the pressure inside the reaction chamber. As a result, the amount of volatile substances supplied to the reactor cannot be determined solely by the flow rate of the carrier gas, making it impossible to precisely and stably control the supply amount. Additionally, if the pressure applied to the gas outlet of the vaporization container becomes greater than the pressure applied to the gas inflow port, volatile substances in the vaporization container may escape from the gas inflow port. Ta.

Particularly in the case of low-pressure vapor phase epitaxial growth of compound semiconductors, a pressure control valve is installed at the source gas inlet of the growth chamber to prevent the pressure inside the growth chamber from being applied to the vaporization vessel. The pressure inside the introduction tube for vaporized volatile substances is usually about 1 atm, and the passage speed of the vaporized volatile substances through the introduction tube is slow, and the volatile substances adhere to the inner wall of the introduction tube, resulting in the growth of mixed crystals. This makes it very difficult to control the composition in the case of impurity doping, control the impurity concentration in the case of impurity doping, and control the steepness of the interface in the case of creating a multilayer thin film structure.

Purpose of the Invention The present invention solves the above-mentioned conventional problems.The present invention is aimed at solving the above-mentioned conventional problems. can be kept constant, and the amount of gas supplied into the reactor can be precisely controlled only by the flow rate of the carrier gas.
Another object of the present invention is to provide a volatile substance vaporization container in which the volatile substance in the vaporization container does not flow out from a carrier gas inlet.

Composition of the Invention The volatile substance vaporization container according to the present invention is equipped with a pressure gauge, a pressure control valve, and a check valve at the inlet of the carrier gas and the outlet of the carrier gas and the vaporized volatile substance, respectively. It is something.

Therefore, by appropriately adjusting the pressure control valves provided at the inlet and outlet, the pressure inside the vaporization container can be kept constant without being affected by external pressure. The amount of vaporized gas is determined only by its temperature, and if the temperature is kept constant, the amount of vaporized gas supplied to the reactor can be precisely controlled by the flow rate of the carrier gas. Furthermore, since check valves are provided at the inlet and outlet, volatile substances in the vaporization container will not flow out from the carrier gas inlet.

DESCRIPTION OF EMBODIMENTS FIG. 2 shows a specific structure of a volatile substance vaporization container according to the present invention. In FIG. 2, the same parts as in FIG. 1 are given the same numbers. As shown in the figure, in this case, pressure gauges 6 and 7 and pressure regulating valves 8 are installed at the inlet of the carrier gas and the outlet of the vaporized volatile substance and carrier gas, respectively.
,9, equipped with a check valve 10.11. The other parts have the same structure as conventional volatile substance vaporization containers.

Using the volatile substance vaporization container according to the present invention, a band gap of 0.95 eV (1.3 μm) was deposited on an InP substrate by a metal organic pyrolysis method (MOOVD method).
The case of growing a GaAs+P quaternary mixed crystal will be described below. FIG. 3 shows a method of connecting the vaporization vessel to the crystal growth apparatus in this case. Round parts in Figure 3 that are the same as those in Figure 2 are given the same numbers. Note that 12 is a mass flow controller, 131d is a magnetic valve 14 is a crystal growth chamber, 15 is a carbon susceptor, 16 is an InP substrate, 17 is a thermocouple,
18 is a high frequency heating coil, 19 is a gas supply port of the crystal growth chamber, 20 is a gas discharge port of the crystal growth chamber, and 21 is a rotary pump. As shown in FIG. 3, the carrier gas and vaporized volatile substance outlet 4 of the vaporization vessel is connected to the gas supply port 19 of the crystal growth chamber, and the carrier gas flow port 1 of the vaporization vessel is connected to a mass 70-controller. Connect 12. By connecting in this manner, carrier gas whose flow rate is precisely controlled can be supplied to the vaporization vessel, and as a result, the amount of volatile substance supplied to the crystal growth chamber can be precisely controlled. In this embodiment, two types of vaporizing containers for volatile substances are used, but the connection methods are the same for both.

In this case, the volatile substances serving as the raw material gas include Zn (C2H5)3. Ga (02H5)s was used as a source material for Ga, PH was used as a source material for P, 5SH was used as a source material for B, and H2 was used as a carrier gas to carry the above-mentioned source materials to the crystal growth chamber. . Initially, the InP substrate 16 was placed on the carbon susceptor 16 in the crystal growth chamber 14.
The temperature is increased to a growth temperature of 650'C by high frequency heating. At this time, PH3 was supplied at 4 ac/min to prevent thermal damage to the surface of the InP substrate 16.

And after that, In(02H5)3: 95 cc/
min, Ga(C2H5)3:1o cc/m
in, PH5: 1o, es cc/min.

Musume sH5: 1.5 cc/min, respectively, was supplied for growth. Nao, In (02Hs) 3y G
Regarding the supply amount of a(C2Hs)s, each
The temperature was kept at 5°C.

The flow rate of H2 supplied to the vaporization container of In(C2Hs)s is the flow rate of H2 supplied to the vaporization container of G''(02H5)s kept at -16℃.The total flow rate is 10
ff/min, the pressure inside the crystal growth chamber during growth is 15
0 Totr. Pressure regulating valves 7, 1 provided at the gas inlet 1 and gas outlet 5 of the In(02H5)3 vaporization container and the Ga(C2Hs)s vaporization container
By adjusting the pressure in the vaporization container,
According to this example, In(C) was maintained at Torr during crystal growth.
Since the pressure in the vaporization vessel of 2H5)s and Ga(02H5) is kept constant, In(02H5)5 and Ga(02H5)
It becomes possible to precisely control the supply ratio of C2H5)5, and InGaA with a composition proportional to each supply ratio.
An sP quaternary mixed crystal was obtained with good reproducibility.

In the embodiments described above, metal organic pyrolysis (MOOVD)
Although the case of an organic metal used as a raw material gas in the vapor phase epitaxial growth of a compound semiconductor by the method (method) has been described, the volatile substance vaporization container according to the present invention can be used not only for other organic metals but also for compound semiconductors. Group V halide compounds used as raw material gas in halide vapor phase epitaxial growth of semiconductors, such as Mu5cjl, , P
It is also possible to use Cl3, AsBr3, etc., and Mo C15, etc. used when forming electrodes by the CVD method.

Effects of the Invention The volatile substance vaporization container according to the present invention is equipped with a pressure gauge, a pressure control valve, and a check valve at the gas inlet and outlet of the vaporization container, so that the pressure inside the vaporization container can be kept constant at all times. The amount of volatile substances supplied to the reactor can be precisely controlled. Therefore, when using it for vapor phase epitaxial growth of compound semiconductors, it is necessary to control the composition for mixed crystal growth, the impurity concentration for impurity doping, the epitaxial growth layer thickness, etc., and when using it for electrode formation by CVD method. In this way, it becomes possible to control the thickness of the electrode precisely and with good reproducibility. In particular, if the reactor is at atmospheric pressure or lower, the pressure inside the volatile substance introduction pipe can also be lowered to below atmospheric pressure.As a result, the vaporized volatile substance passes through the introduction pipe at a faster rate, causing it to stick to the inner wall of the pipe. is reduced, the above-mentioned effects are even greater, and the practical effects are very great.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram of a conventional volatile substance vaporization container, FIG. 2 is a schematic diagram of a volatile substance vaporization container in an embodiment of the present invention, and FIG. 3 is a schematic diagram of a volatile substance vaporization container in an embodiment of the present invention. It is a connection diagram of a vaporization container to a crystal growth system. 1... Carrier gas inlet, 2...
Outlet for carrier gas and vaporized volatile substances, 3
...Volatile substance, 6,7...Pressure gauge, 8
, 9...Pressure control valve, 10.11...
Check valve, 12...Mass flow controller,
14...Crystal growth chamber, 15...Carbon susceptor, 16...InP substrate, 19.
...Gas supply port for the crystal growth chamber. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure 281

Claims (1)

[Claims] A device for vaporizing volatile substances, characterized in that a gas inlet and a gas outlet are each equipped with a pressure gauge, a pressure control valve, and a check valve.