JP2004327534A - Organic metal material vapor phase epitaxy device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problem wherein, since a thermostatic chamber 3 has an open top in the material gas feeder 1 of a conventional organic metal vapor phase epitaxy device, heat radiates into the air from the surface of a cooling medium 2 to reduce the cooling medium in temperature uniformity, and it is hard to keep the cooling medium 2 where a temperature change occurs due to radiation of heat high in temperature stability (temperature is restrained from changing with time). <P>SOLUTION: The material gas feeder 101 of the organic metal vapor phase epitaxy device is equipped with a closed thermostatic chamber 102 filled with the cooling medium 2, a material case 5 housing an organic metal material 4, a carrier gas feeding tube 7 feeding carrier gas 6a, material gas extracting piping 8 extracting the carrier gas 6b containing the material gas, cooling medium feeding piping 103 successively feeding a new cooling medium 2 which is controlled and kept at a previously set temperature into the thermostatic chamber 102 from outside, and cooling medium discharging piping 104 successively discharging the cooling medium 2 from the thermostatic chamber 102. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention provides, for example, an organic apparatus having a source gas supply unit for introducing a carrier gas into a source container and extracting the source gas while cooling a source container containing an organic metal source to be epitaxially grown on a semiconductor substrate with a refrigerant. The present invention relates to a metal vapor deposition apparatus.
[0002]
For example, when a crystal thin film of a compound semiconductor such as GaAs, AlGaAs, GaAsP, or InGaAs is epitaxially grown on a predetermined semiconductor substrate, an organic metal raw material of each element constituting these compound semiconductors is supplied into the reaction furnace in a gaseous state. A metal organic chemical vapor deposition apparatus having a raw material gas supply unit is used.
[0003]
In general, an organometallic raw material has a property of igniting when it reacts with air, so that it is housed and handled in a closed dedicated raw material container.When generating a raw material gas, the vapor pressure of the surface of the organic metal raw material is reduced. It is cooled with a refrigerant to keep it as constant as possible.
[0004]
FIG. 2 is a cross-sectional view of an example of a source gas supply unit of a conventional metal organic chemical vapor deposition apparatus.
[0005]
The raw material gas supply unit 1 stores an organic metal raw material 4 immersed in the upper open-type constant temperature bath 3 filled with a refrigerant 2 such as water or a fluorine-based inert liquid. A raw material container 5, a carrier gas supply pipe 7 for supplying a carrier gas 6 a into the raw material container 5, and a raw gas extraction pipe 8 for extracting a carrier gas 6 b containing the raw material gas from the raw material container 5. Have been.
[0006]
The raw material container 5 is originally provided with two pipes. One is a gas introduction pipe 9, which has one end immersed in the organometallic raw material 4 in the raw material container 5, and serves to generate bubbles of the carrier gas 6 a. The other one is a gas outlet pipe 10, which serves to take out a carrier gas 6 b containing a source gas generated from the surface of the organic metal source 4. These pipes 9 and 10 are connected to a carrier gas supply pipe 7 and a source gas extraction pipe 8 via a nipple 11, respectively. Further, an opening / closing valve 12 is provided in the middle of each of the pipes 7, 8, 9, 10 so that the flow and stop of the carrier gas 6a, 6b can be freely performed.
[0007]
The reason why the thermostatic bath 3 is opened upward is to facilitate putting the refrigerant 2 and the raw material container 5 in and out, and to release heat from the refrigerant 2 to the atmosphere and reduce the temperature rise of the refrigerant 2. is there.
[0008]
In the method of vaporizing the organometallic raw material 4 which is solid or liquid at normal temperature in the raw material gas supply unit 1, for example, hydrogen (H ₂ ) is sent as a carrier gas 6a into a closed raw material container 5 and the carrier gas is supplied. The liquid material is bubbled and vaporized by 6a, or the solid material is vaporized by sublimation. Here, the organometallic raw material 4 in the raw material container 5 is cooled by the refrigerant 2 and the temperature uniformity and the temperature stability (temperature over time) as much as possible within the range of the cooling capacity determined by the amount of the stored refrigerant 2. Is kept constant). Then, the carrier gas 6b containing the vaporized source gas is transported to a reaction furnace (not shown) and a crystal thin film (not shown) is epitaxially grown on a semiconductor substrate (not shown) by utilizing thermal decomposition or the like.
[0009]
Here, in order to grow the thickness of the crystal thin film (not shown) to a uniform thickness, it is important that the source gas is supplied to the reaction furnace (not shown) stably. It is necessary that the vapor pressure in the raw material container 5 be stable, and it is important to keep the surface temperature of the organometallic raw material 4 constant at all times in order to stabilize the vapor pressure.
[0010]
For this reason, for example, a device has been devised to improve the temperature uniformity of the refrigerant 2 by disposing the thermocouple 13 in the refrigerant 2 and stirring the refrigerant 2 with the stirrer 14 based on the measured value. (For example, Patent Document 1).
[0011]
[Patent Document 1]
JP-A-9-227283 (page 2, paragraph 0008, FIG. 3)
[0012]
[Problems to be solved by the invention]
However, in the source gas supply unit 1 of the conventional metal-organic vapor phase epitaxy apparatus, since the thermostat 3 is open upward, heat is released from the surface of the refrigerant 2 to the atmosphere, and the upper and lower sides of the refrigerant 2 are inevitably. And the temperature difference which cannot be ignored was generated, and the temperature uniformity was reduced. In addition, even if the temperature uniformity can be improved by stirring the refrigerant 2 having undergone the temperature change due to the heat radiation with the stirrer 14, the temperature stability (keeping the temperature constant over time) is ensured. It was difficult.
[0013]
An object of the present invention is to improve the temperature uniformity and temperature stability of a coolant for cooling a raw material container containing an organometallic raw material, and to increase the temperature of a raw material gas capable of growing a crystal thin film having a uniform thickness on a crystal substrate. An object of the present invention is to provide a metal organic chemical vapor deposition apparatus provided with a supply unit.
[0014]
[Means for Solving the Problems]
The metal organic chemical vapor deposition apparatus of the present invention is:
at least,
A thermostat bath filled with refrigerant,
A raw material container containing an organic metal raw material to be immersed in a coolant and epitaxially grown,
A carrier gas supply pipe for supplying a carrier gas into the raw material container,
In a metal organic chemical vapor deposition apparatus including a source gas supply unit having a source gas extraction pipe for extracting a carrier gas containing a source gas from a source container,
A refrigerant supply pipe for sequentially supplying the refrigerant into the constant temperature bath,
A refrigerant discharge pipe for sequentially discharging the refrigerant in the constant temperature bath,
An organometallic vapor phase epitaxy apparatus characterized in that a refrigerant in a thermostat can be exchanged.
[0015]
BEST MODE FOR CARRYING OUT THE INVENTION
FIG. 1 shows a cross-sectional view of an example of the source gas supply unit of the metal organic chemical vapor deposition apparatus of the present invention. The same parts as those in FIG.
[0016]
The raw material gas supply unit 101 is, for example, a closed type thermostatic bath 102 characterized by the present invention filled with a refrigerant 2 such as water or a fluorinated inert liquid, and immersed in the refrigerant 2, A raw material container 5 containing and sealing the raw material 4, a carrier gas supply pipe 7 for supplying a carrier gas 6 a into the raw material container 5, and a raw gas extraction pipe for extracting a carrier gas 6 b containing the raw material gas from the raw material container 5. 8, a refrigerant supply pipe 103 for sequentially supplying new refrigerant 2 from outside to the thermostat 102, and a refrigerant discharge pipe 104 for sequentially discharging the refrigerant 2 from the thermostat 102. And a refrigerant temperature control unit 105 that controls the temperature of the refrigerant 2 supplied to the constant temperature bath 102 to a desired temperature, which is a feature of the present invention.
[0017]
The raw material container 5 is originally provided with two pipes. One is a gas introduction pipe 9, which has one end immersed in the organometallic raw material 4 in the raw material container 5, and serves to generate bubbles of the carrier gas 6 a. The other one is a gas outlet pipe 10, which serves to take out a carrier gas 6 b containing a source gas generated from the surface of the organic metal source 4. These pipes 9 and 10 are connected to a carrier gas supply pipe 7 and a source gas extraction pipe 8 via a nipple 11, respectively. Further, an opening / closing valve 12 is provided in the middle of each of the pipes 7, 8, 9, 10 so that the flow and stop of the carrier gas 6a, 6b can be freely performed.
[0018]
The constant temperature bath 102 includes a bottomed cylindrical container portion 102a and a lid portion 102b, and the attached stopper 107 is attached to the container portion 102a via a sealing material such as an O-ring 106, for example. The thermostat 102 can be hermetically closed by attaching the lid 102b using the. Further, the wall material of the container portion 102a and the lid portion 102b has a double structure in which a space 102c is provided inside the wall material, and the space 102c is in a vacuum state, and uniform excellent heat insulating effect is obtained over the entire surface. You can get it.
[0019]
In the middle of the refrigerant supply pipe 103 and the refrigerant discharge pipe 104, an opening / closing valve 12 is provided, respectively, so that the refrigerant 2 can flow and stop freely. During the source gas supply operation, the operation is performed while the refrigerant 2 in the constant temperature bath 102 is being replaced with a new refrigerant 2 whose temperature is controlled during the supply operation.
[0020]
In the method of vaporizing the organometallic raw material 4 which is solid or liquid at room temperature in the raw material gas supply unit 101, for example, hydrogen (H ₂ ) is sent as a carrier gas 6a into a closed raw material container 5, and the carrier gas 6a The liquid raw material is vaporized by bubbling, or the solid raw material is vaporized by sublimation. Here, since the thermostat 102 is not an open top type but a closed type as in the prior art, there is no heat radiation from the surface of the refrigerant 2 to the atmosphere, and no temperature difference occurs in the refrigerant 2 due to heat radiation. Further, since the refrigerant 2 in the thermostat 102 is always replaced with a new refrigerant 2 controlled to a preset temperature, the cooling capacity is limited by the amount of the refrigerant 2 stored in the thermostat as in the conventional case. It will not be done. Then, the carrier gas 6b containing the vaporized source gas is transported to a reaction furnace (not shown) and a crystal thin film (not shown) is epitaxially grown on a semiconductor substrate (not shown) by utilizing thermal decomposition or the like.
[0021]
In this way, by improving the temperature uniformity and temperature stability (keeping the temperature constant over time) of the refrigerant 2 that cools the organometallic raw material 4 in the raw material container 5, the vapor on the surface of the organic metal 4 is improved. The pressure is kept constant, so that a higher quality source gas can be supplied.
[0022]
In the above description, the method has been described in which the temperature of the refrigerant 2 sequentially supplied into the constant temperature bath 102 is controlled and supplied to a preset temperature, but a temperature sensor (not shown) is disposed in the constant temperature bath 102. The control may be performed based on a signal from a temperature sensor (not shown). In addition, although the description has been made by setting the inside of the wall material of the thermostat 102 to a vacuum state, it is needless to say that the wall material may be loaded with a heat insulating material such as polyurethane, glass wool, or foamed polyethylene.
[0023]
【The invention's effect】
According to the source gas supply unit 101 of the metal organic vapor phase epitaxy apparatus of the present invention, since the thermostatic bath 102 filled with the refrigerant 2 is a closed type, there is no heat radiation from the surface of the refrigerant 2 to the atmosphere, and And temperature uniformity at the lower side is small and temperature uniformity is improved. Further, since the refrigerant 2 in the thermostat 102 is sequentially replaced with a new refrigerant 2 controlled to a desired temperature, the temperature stability (keeping the temperature constant over time) is excellent. Further, when the wall material of the thermostat 102 has a double structure and the space 102c inside the wall material is in a vacuum state, an excellent heat insulating effect can be obtained over the entire surface, and the temperature uniformity and the temperature stability (the temperature is kept constant over time). Can be maintained).
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of an example of a source gas supply unit of a metal organic chemical vapor deposition apparatus of the present invention. FIG. 2 is a cross-sectional view of an example of a source gas supply unit of a conventional metal organic chemical vapor deposition apparatus.
DESCRIPTION OF SYMBOLS 1 Conventional raw material gas supply part 2 Refrigerant 3 Conventional upward-opening constant temperature bath 4 Organometallic raw material 5 Raw material container 6a Carrier gas 6b Carrier gas containing raw material gas 7 Carrier gas supply piping 8 Raw material gas extraction piping 9 Gas introduction piping REFERENCE SIGNS LIST 10 gas outlet pipe 11 nipple 12 on-off valve 13 thermocouple 14 stirrer 101 raw material gas supply section 102 of the present invention closed type constant temperature bath 102 a container section 102 b lid section 103 of the present invention refrigerant supply pipe 104 refrigerant discharge pipe 105 refrigerant temperature control Part 106 O-ring 107 Stopper

Claims (5)

at least,
A thermostat bath filled with refrigerant,
A raw material container that is immersed in the refrigerant and contains an organic metal raw material to be epitaxially grown,
A carrier gas supply pipe for supplying a carrier gas into the raw material container,
In an organometallic vapor phase epitaxy apparatus including a source gas supply unit having a source gas extraction pipe for extracting a carrier gas containing a source gas from the source container,
A refrigerant supply pipe for sequentially supplying the refrigerant into the constant temperature bath,
A refrigerant discharge pipe for sequentially discharging the refrigerant in the constant temperature bath,
An organometallic vapor phase epitaxy apparatus wherein the refrigerant in the thermostat is exchangeable. 2. The metal organic chemical vapor deposition apparatus according to claim 1, further comprising a refrigerant temperature control unit that controls a temperature of the refrigerant sequentially supplied into the constant temperature bath. 3. 3. The metal organic chemical vapor deposition apparatus according to claim 1, wherein the constant temperature bath is a closed type constant temperature bath. The metal organic chemical vapor deposition apparatus according to claim 1, wherein the wall material of the constant temperature bath has a double structure in which a space is provided inside the wall material. The metalorganic vapor phase epitaxy apparatus according to claim 4, wherein the space inside the wall material of the constant temperature bath is in a vacuum state or is filled with a heat insulating material.

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