JP3219184B2 - Organometallic supply and organometallic vapor phase epitaxy - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an organometallic supply apparatus and an organometallic vapor phase epitaxy apparatus used for crystal growth of III-V compound semiconductors. In particular, the present invention relates to an organic metal supply apparatus for ensuring stable supply of an organic metal gas as a raw material, and to an organic metal vapor phase epitaxy apparatus capable of maintaining a stable supply ratio of a plurality of raw materials.

[0002]

2. Description of the Related Art Metalorganic vapor phase epitaxy (MOVPE) using an organic metal (organometallic compound) as a raw material is widely used as a method for growing a group III-V compound semiconductor crystal. In the metal organic chemical vapor deposition method, In, G, which is a group III raw material, is used.
a, Al are supplied to the reaction tube in the form of an organic metal gas. What supplies the organic metal is an organic metal supply device. The group V raw material is supplied in the form of a hydride gas.

Referring to FIG. 7, a conventional organic metal supply apparatus 1 is shown.
Will be described. The bubbler 3 filled with the organic metal raw material 2 is immersed in a constant temperature bath 4 to keep the temperature of the bubbler constant, thereby keeping the vapor pressure of the organic metal at a constant value. Since many organic metals are liquid at around room temperature, a predetermined flow rate of a carrier gas (mainly using hydrogen) is supplied into the bubbler by the mass flow controller 5 and bubbling is performed so that the vapor of the organic metal is contained in the carrier gas. Mix. This mixed gas is supplied to the reaction tube. In the actual operation, when the raw material is not supplied to the reaction tube, for example, at the time of purging, the air valve 9a is opened and the air valves 9b, 9b are opened.
When the material is supplied, the air valve 9a is closed, and 9b and 9c are opened. The pressure in the bubbler is detected by a diaphragm type pressure gauge 6 and controlled by a pressure control device 8 so as to be maintained at a predetermined pressure by a control valve 7. The supply amount of organometallic gas per unit time is
It is determined by the vapor pressure of the organic metal determined by the temperature of the thermostat, the pressure in the bubbler, and the amount of the carrier gas flowing into the bubbler. Since the flow rate of mass flow controllers currently on the market is very stable against environmental changes, it is considered that the factor hindering the stable supply of organometallic gas is mainly the fluctuation of the vapor pressure of organometallic gas in the bubbler. Have been. In fact, depending on the state of the organic metal in the bubbler, the partial pressure of the organic metal in the bubbler may not reach the saturated vapor pressure, and the temperature of the bubbler changes due to the change in the ambient temperature, and the value of the saturated vapor pressure fluctuates Sometimes.

Referring to FIG. 8, another method of supplying an organic metal raw material and a supply apparatus 11 will be described. Trimethylindium (TMI), which is an In material used for indium phosphide (InP) -based growth, is a solid at around room temperature, and therefore has a large fluctuation in the supply amount compared to other liquid organometallic materials, which is a problem. Was. This is because the needle-like crystals which were initially needle-like crystals are fused with each other over a long period of use, and the surface area of the crystals changes and gradually decreases. If the surface area in contact with the carrier gas is not sufficiently large, it will not mix with the carrier gas by the vapor pressure determined by the temperature, and the supply amount will decrease. To solve the problem,
A method of directly controlling steam with a mass flow controller without using a carrier gas has been used. The bubbler 3 containing the TMI2A and the mass flow controller 4 are put in a thermostat 4 and kept at about 80 ° C. The mass flow controller cannot control the flow rate unless there is a pressure difference between the outlet side and the inlet side by a predetermined value. Therefore, the pressure in the reaction tube is limited to the vapor pressure of the organometallic or less. The vapor pressure of TMI at 80 ° C. is at most 50 Torr. The pressure in the reaction tube of a metalorganic vapor phase epitaxy, which is widely used, is 7
Since it is in the range of 0 to 100 Torr, it is difficult to use the supply device of FIG.

Next, a metal organic chemical vapor deposition apparatus will be described. As shown in FIG. 9, FIG. 7 or FIG.
And a hydride gas cylinder 12a,
Pipe 14 using a metalorganic vapor phase epitaxy apparatus having
The raw material is supplied to the reaction tube 15 through the reactor to grow the compound semiconductor. FIG. 9 shows a bubbler 3a,
3b, 3c, thermostats 4a, 4b, 4c, mass flow controllers 5a, 5b, 5c, pressure gauges 6a, 6b, 6c,
Supply devices 1a, 1b, 1c having control valves 7a, 7b, 7c and pressure controllers 8a, 8b, 8c
Is shown. The illustration of the air valve is omitted. The supply amount of the hydride gas depends on the mass flow controller 13a,
13b. In order to control the composition of the compound semiconductor film, it is necessary to control the ratio of the supply amounts of the respective raw materials. A conventional method of controlling the supply ratio is to maintain the flow rates of the respective organic metal supply devices and the mass flow controllers 5a to 5c, 13a, and 13b of the hydride gas cylinders at predetermined values. Constant temperature bath 4a-4c
Is maintained at a constant temperature and the pressure in the bubblers 3a to 3c is maintained at a constant pressure, so that a raw material proportional to the flow rate of the mass flow controller is supplied.

However, depending on the state of the organic metal in the bubbler, the partial pressure of the organic metal in the bubbler may not reach the saturated vapor pressure, and the value of the saturated vapor pressure may fluctuate due to a change in the ambient temperature. Therefore, the supply ratio fluctuates. Further, the supply ratio fluctuates due to a change in the temperature of the pipe.

[0007]

SUMMARY OF THE INVENTION It is a first object of the present invention to provide an organic metal supply apparatus in which the supply of organic metal is stable. A second object is to provide a metal organic chemical vapor deposition apparatus in which the supply ratio between organic metals is stable.

[0008]

SUMMARY OF THE INVENTION An organic metal supply apparatus according to the present invention is characterized in that a carrier gas is bubbled in a bubbler while the pressure inside the bubbler containing an organic metal is maintained at a predetermined value. Gas supply means, and a partial pressure detection means for detecting the partial pressure of the organic metal gas in the carrier gas downstream of the bubbler, wherein the signal from the partial pressure detection means The apparatus is characterized in that a means for controlling the pressure in the bubbler in the gas supply means to keep the partial pressure of the organic metal gas in the carrier gas constant.

Further, the organic metal supply device includes gas supply means for supplying the organic metal gas by bubbling a carrier gas in the bubbler while maintaining the pressure in the bubbler containing the organic metal at a predetermined value. A partial pressure detecting means downstream of the bubbler and detecting a partial pressure of the organic metal gas in the carrier gas, wherein a signal from the partial pressure detecting means controls the inside of the bubbler in the gas supplying means. And a means for controlling the flow rate of the carrier gas flowing into the device to keep the flow rate of the organometallic gas supplied per unit time constant.

Here, the partial pressure detecting means may be an ultrasonic cell, and the partial pressure detecting means may be a quadrupole mass analyzer.

The metalorganic vapor phase epitaxy apparatus according to the present invention supplies the organic metal gas by bubbling the carrier gas in the bubbler while maintaining the pressure in the bubbler containing the organic metal at a predetermined value. A plurality of gas supply means, a pipe for merging and transporting the organic metal gas supplied from the plurality of gas supply means to the reaction tube, and a plurality of organic metal gases contained in the carrier gas attached to the pipe; A metal-organic vapor phase epitaxy apparatus having a partial pressure detecting means for detecting a partial pressure, comprising means for controlling a pressure in a bubbler containing a corresponding organic metal according to a partial pressure of each organic metal gas. It is characterized by being.

Further, the organic metal vapor phase epitaxy apparatus supplies a plurality of organic metal gases by bubbling a carrier gas in the bubbler while maintaining the pressure in the bubbler containing the organic metal at a predetermined value. A gas supply means, a pipe for merging and transporting the organic metal gases supplied from the plurality of gas supply means to the reaction tube, and a partial pressure of the plurality of organic metal gases contained in the carrier gas and attached to the pipe. And a means for controlling the flow rate of the carrier gas flowing into the bubbler containing the corresponding organometallic, according to the partial pressure of each organometallic gas. It is characterized by having.

Here, the partial pressure detecting means may be a quadrupole mass analyzer.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the present invention, in order to solve the first problem, a partial pressure of an organic metal gas in a carrier gas containing an organic metal gas supplied from a bubbler is detected, and the detected partial pressure is set to a constant value. Control the pressure inside the bubbler to keep Further, the flow rate of the carrier gas flowing into the bubbler is controlled so that the amount of the organic metal gas supplied per unit time from the bubbler is maintained at a constant value.

In order to solve the second problem, a partial pressure ratio of each raw material is detected in a pipe where raw gas supplied from each bubbler joins, and each raw gas supply means is controlled accordingly.

The supply amount [s] (mole / min.) Of the organometallic gas supplied from the organometallic supply device is represented by the following equation.

[0017]

(Equation 1)

Where P _s is the saturated vapor pressure of the organometallic gas,
P _B is the pressure in the bubbler, and l (sccm) is the flow rate of the carrier gas (however, an approximation of P _s ≪ P _B was used). Actually, depending on the state of the organic metal in the bubbler, the partial pressure of the organic metal in the bubbler may not reach the saturated vapor pressure, or the value of the saturated vapor pressure may fluctuate due to a change in the ambient temperature. Even if such a fluctuation occurs, if the pressure P _B in the bubbler is adjusted and P _s / P _B is kept constant, the supply amount [s] of the organic metal can be kept constant, and even keeping the lP _s constant by adjusting the flow rate l of the carrier gas flowing into the bubbler is possible to keep the supply amount of the organic metal [s] constant. Methods for measuring the partial pressure of the organometallic gas include a method using an ultrasonic cell utilizing a phenomenon in which the ultrasonic velocity in the mixed gas changes according to the mixing ratio of the gas, and a method using a quadrupole mass spectrometer.

In the metal organic chemical vapor deposition apparatus of the present invention,
Measure the partial pressure of each source gas in the gas flowing into the reaction tube,
Since the supply amount of each organic metal supply device is controlled so that the ratio of the partial pressures becomes constant, it is possible to provide a metal organic chemical vapor deposition apparatus in which the supply ratio of each organic metal is stable. As a method for measuring the partial pressure of the organic metal gas, there is a method using a quadrupole mass spectrometer. The supply amount of each organic metal supply device is controlled so that the ratio of the signal intensity corresponding to each organic metal becomes constant.

[0020]

Embodiment 1 FIG. 1 shows a first embodiment of the present invention. The organic metal supply device 21 converts the bubbler 3 filled with the organic metal raw material 2 into a constant temperature bath 4.
To maintain the vapor pressure of the organometallic at a constant value by keeping the temperature of the bubbler constant. The mass flow controller 5 supplies a predetermined flow rate of the carrier gas into the bubbler, and bubbling mixes the organic metal vapor into the carrier gas. The mixed gas is supplied to the reaction tube. The pressure in the bubbler is detected by a diaphragm type pressure gauge 6, and is controlled by a control device 22 so as to be maintained at a predetermined pressure by a control valve 7.
Downstream of the bubbler, between the manometer 6 and the control valve 7, there is a partial pressure measuring device 23. The partial pressure of the gas is measured by using the phenomenon that the ultrasonic velocity in the mixed gas changes with the mixing ratio of the gas. The information on the partial pressure is sent to the control device 22, and the pressure in the bubbler 3 is controlled by the control valve 7 so that the partial pressure of the organic metal gas becomes a predetermined value.
The feature of this control method is that the amount of the organic metal supplied can be controlled without changing the flow rate of the mass flow controller 5, so that the amount of the carrier gas flowing into the reaction tube does not change.

Next, the principle will be described. The number of moles of hydrogen flowing into the bubbler per unit time is [H ₂ ] (mo
le / min. ) And the number of moles of the organic metal mixed into the hydrogen in the bubbler is [s] (mole / min.), The ratio P _s / of the vapor pressure of the organic metal to the total pressure in the bubbler in a steady state. P _B is [s] / ([s] + [H
₂ ]), the supply amount [s] (mole / min.) Of the organometallic gas supplied from the bubbler is represented by the following equation.

[0022]

(Equation 2)

However, an approximation of P _s ≪P _B was used. In the partial pressure measurement device described above, it will measure P _s.
Since the flow rate of the carrier gas is controlled by the mass flow controller, the number of moles flowing per unit time can be obtained by dividing the flow rate of the mass flow controller by the volume in the standard state. Therefore, the flow rate l (mole / mi) of the carrier gas is obtained.
n. ), The following equation holds.

[0024]

(Equation 3)

As is clear from the above equation, if the ratio P _s / P _B between the vapor pressure of the organic metal and the total pressure in the bubbler is kept constant, the supply amount of the organic metal is kept constant. Even if the vapor pressure P _s of the organic metal decreases for some reason, if the conductance of the control valve is controlled so as to lower the bubbler pressure P _B and keep P _s / P _B constant, the supply amount of the organic metal becomes Be kept constant. In fact, depending on the state of the organic metal in the bubbler, the partial pressure of the organic metal in the bubbler may not reach the saturated vapor pressure, and the temperature of the bubbler changes due to the change in the ambient temperature, and the value of the saturated vapor pressure fluctuates Sometimes. However, even if there is such a variation, the ratio P _s between the vapor pressure of the organometallic and the total pressure in the bubbler is obtained.
By keeping / P _B constant, it is possible to keep the supply amount [s] of the organic metal constant.

Embodiment 2 FIG. 2 shows a second embodiment of the present invention. The organic metal supply device 31 converts the bubbler 3 filled with the organic metal raw material 2 into a constant temperature bath 4.
To maintain the vapor pressure of the organometallic at a constant value by keeping the temperature of the bubbler constant. The mass flow controller 5 supplies a predetermined flow rate of the carrier gas into the bubbler, and bubbling mixes the organic metal vapor into the carrier gas. The mixed gas is supplied to the reaction tube. The pressure in the bubbler is detected by a diaphragm type pressure gauge 6 and controlled by a pressure control device 8 so as to be maintained at a predetermined pressure by a control valve 7. Downstream of the bubbler, between the manometer 6 and the control valve 7, there is a partial pressure measuring device 23. The partial pressure of the gas is measured by using the phenomenon that the ultrasonic velocity in the mixed gas changes with the mixing ratio of the gas. The information on the partial pressure is sent to the control device 22 and controls the flow rate of the mass flow controller so that the product of the partial pressure of the organometallic gas and the flow rate of the carrier gas keeps a constant value. In this control method, the supply amount of the organic metal gas is kept constant, but the flow rate of the mass flow controller changes, so that the amount of the carrier gas flowing into the reaction tube changes.

According to equation (3) described earlier, Keeping the product P _s l of the carrier gas flow rate l flowing to the partial pressure P _s and bubbler organometallic constant supply amount of the organic metal Be kept constant. Be the vapor pressure P _s of the organometallic is reduced for some reason, the carrier gas flow rate l is increased, by controlling the flow rate of the mass flow controller to maintain the lP _s constant, holding constant the supply amount of the organometallic Dripping. In fact, depending on the state of the organic metal in the bubbler, the partial pressure of the organic metal in the bubbler may not reach the saturated vapor pressure, and the temperature of the bubbler changes due to the change in the ambient temperature, and the value of the saturated vapor pressure fluctuates Sometimes. However, even if such variations, Keeping the product P _s l of the carrier gas flow rate l flowing to the partial pressure P _s and bubbler organometallic constant supply amount of the organometallic [s] a It can be kept constant.

Embodiment 3 FIG. 3 shows a third embodiment of the present invention. The organic metal supply device 41 converts the bubbler 3 filled with the organic metal raw material 2 into a constant temperature bath 4.
To maintain the vapor pressure of the organometallic at a constant value by keeping the temperature of the bubbler constant. The mass flow controller 5 supplies a predetermined flow rate of the carrier gas into the bubbler, and bubbling mixes the organic metal vapor into the carrier gas. The mixed gas is supplied to the reaction tube. The pressure in the bubbler is detected by a diaphragm type pressure gauge 6 and controlled by a control device 42 so as to be maintained at a predetermined pressure by a control valve 7.
Downstream of the bubbler 3, there is a partial pressure measuring device 43 between the control valve 7 and the reaction tube. The ratio I _MO / I _H2 of the signal intensity I _H2 corresponding to hydrogen and the signal intensity I _MO corresponding to the organic metal is measured by using quadrupole mass spectrometry. Information on the signal strength ratio is sent to the controller 42, where the signal strength ratio I _MO /
The pressure in the bubbler 3 is controlled by the control valve 7 so that I _H2 becomes a predetermined value. The feature of this control method is that the supply amount of the organic metal can be controlled without changing the flow rate of the mass flow controller, so that the amount of the carrier gas flowing into the reaction tube does not change.

Next, the principle will be described. Explained earlier
According to equation (3), the vapor pressure of the organometallic and the pressure in the bubbler
Ratio P to total pressure_s / P_B Can be maintained at a constant
The salary is kept constant. Measured with a quadrupole mass spectrometer
Signal strength ratio I determined_MO/ I _H2Is P_s ≪P_B To approximate
In the P_s / P_B It is an amount proportional to. Accordingly
And I_MO/ I_H2Control valve to keep the
By controlling the conductance of_s / P_B Is kept constant
As a result, the organic metal supply is kept constant. what
For some reason, the vapor pressure P of the organic metal_s Is reduced, I_MO
/ I_H2Pressure P to keep the pressure constant_B Lower,
P_s / P_B Control valve so that
By controlling the conductance, the supply of organic metal will be constant.
Will be kept. In fact, depending on the state of the organometallic in the bubbler
Means that the partial pressure of the organic metal in the bubbler reaches the saturated vapor pressure
May not be possible,
May change, and the value of the saturated vapor pressure may fluctuate.
However, even with such fluctuations, hydrogen
Signal strength I_H2And the signal intensity I corresponding to the organic metal_MOof
Ratio I_MO/ I_H2Can be maintained at a constant
It is possible to keep the supply amount [s] constant.

Embodiment 4 As a fourth embodiment of the present invention, an example of a metal organic chemical vapor deposition apparatus will be described. The group III raw material uses an organic metal gas, and the group V raw material uses a hydride gas. Figure 4 shows the configuration
Shown in In this figure, a solid line 52 indicates a gas pipe, and a dotted line 53 indicates a flow of a control signal. Mass flow controllers 5a, 5b, 5c and bubblers 3a, 3 respectively
b, 3c, a plurality of diaphragm-type pressure gauges 6a, 6b, 6c, a plurality of organic metal supply devices 51a, 51b, 51c including control valves 7a, 7b, 7c, and hydride gas cylinders 12a, 12b. . The supply amount of the hydride gas is controlled by the mass flow controllers 13a and 13b. Each of the organic metal supply devices 51a to 51c and the cylinder 1
The pipes from 2a to 12b are put together and connected to the reaction tube 54. A partial pressure measuring device 55
Place. The partial pressure measuring device 55 in the present embodiment is a quadrupole mass analyzer. Signals relating to the pressures in the bubblers 3a to 3c of the supply devices 51a to 51c are sent to the control device 56 from the diaphragm type pressure gauges 6a to 6c. On the other hand, the partial pressure of each source gas can be estimated from the signal intensity corresponding to each source gas. However, the amount actually required is the signal intensity ratio of the source gas. For example, in the case of growing InGaAsP, the signal intensity of an In I _{an In} and the ratio of the Ga of the signal intensity I _Ga I _Ga / I _In, and As signal strength I _As the P signal intensity I _P ratio I _As / _IP is important. In order to keep this intensity ratio constant, a signal for controlling the pressure in the bubbler of each organic metal supply unit is sent to each of the control valves 7a to 7c via the control device 56 for the group III raw material. A signal for controlling the flow rate of the mass flow controllers 13a to 13b provided for each cylinder is sent to each control valve 7a to 7c, and a signal for controlling the flow rate of the mass flow controllers 13a to 13b provided for each cylinder is sent for the group V raw material.

Embodiment 5 As a fifth embodiment of the present invention, another example of a metal organic chemical vapor deposition apparatus will be described. The group III raw material uses an organic metal gas, and the group V raw material uses a hydride gas. The configuration is shown in FIG. In this figure, a solid line 52 indicates a gas pipe, and a dotted line 53 indicates a flow of a control signal. The organic metal supply device shown in FIG.
b, 3c, thermostats 4a, 4b, 4c, mass flow controllers 5a, 5b, 5c, diaphragm type pressure gauges 6a, 6b,
6c, a plurality of organic metal supply devices 21a, 21b, 21c having control valves 7a, 7b, 7c, control devices 22a, 22b, 22c and partial pressure measuring devices 23a, 23b, 23c using ultrasonic cells, and hydrogen It has gas cylinders 12a and 12b. The supply amount of the hydride gas is controlled by the mass flow controllers 13a and 13b. The pipes from the respective organic metal supply devices 21a to 21c and the cylinders 12a to 12b are collectively connected to the reaction tube 54. A partial pressure measurement device 5
5 is arranged. The partial pressure measuring device 55 in the present embodiment is a quadrupole mass analyzer. The partial pressure of each source gas can be estimated from the signal intensity corresponding to each source gas. However, the amount actually required is the signal intensity ratio of the organometallic gas. For example, in the case of growing InGaAsP, the ratio I _Ga of the signal intensity I _{In of In} and the signal intensity I _Ga of _{Ga is In.}
/ I _In , and the signal strength I _{As of As} and the signal strength I _{P of P}
Ratio I _As / I _P becomes important. In order to keep this intensity ratio constant, a signal for controlling the flow rate of each organic metal supply device and the mass flow controller of the cylinder via the control device 57 is sent to each of the mass flow controllers 5a to 5c and 13a to 1c.
Send to 3b.

In Embodiments 4 and 5 described above,
The location where the partial pressure of each source gas in the gas is measured is not limited to the inlet of the reaction tube, and may be measured by inserting a capillary near the substrate in the reaction tube as shown in FIG. FIG. 6 shows a cross-sectional view (FIG. 6A) and a top view (FIG. 6B) of the horizontal reaction tube 61 of the metal organic chemical vapor deposition apparatus. The reaction tube has a double tube configuration of an outer tube that maintains airtightness and an inner tube 61 that regulates the flow of the raw material gas contained therein, but FIG. 6 shows only the inner tube 61. Inner tube 6
1 is provided with a notch, and the substrate 62 is arranged so that its surface is in contact with the source gas. The substrate 62 includes a rotating shaft 6
It is mounted on a susceptor 63 rotating by 3A,
It is heated to a predetermined temperature by the susceptor. From the left side of the drawing, the organic metal gas and the hydride gas which are the raw materials
1 is supplied. The supplied gas is thermally decomposed near the substrate and is deposited on the substrate. If a quartz capillary 64 is inserted above the substrate, a gas near the substrate is sampled, and analyzed by a quadrupole mass spectrometer, the partial pressure of each organometallic gas in the gas is measured. Since it is possible to measure the partial pressure of each organometallic gas in the gas immediately before the gas is deposited, control with higher stability is possible.

In the vapor phase growth apparatus shown in FIG. 5, a supply apparatus 41 shown in FIG. 3 can be used instead of the organic metal supply apparatuses 21a to 21c.

In the embodiment of FIGS. 4 and 5, three III
Although a group material (organic metal) supply device and two cylinders for supplying a group V material (hydride gas) have been shown, they may be used in a number corresponding to the number of necessary materials.

In the above description, the description has been made on the assumption that the vapor pressure of the organic metal is much smaller than the pressure in the bubbler. This approximation holds well for commonly used Group III organometallics. Group V organic metals, such as tertiary butyl phosphine (TBP) and tertiary butyl arsine (TBA), which have recently been used, have a vapor pressure near room temperature of 100 to 20.
In some cases, the approximation of P _s ≪P _B does not hold because it reaches 0 Torr. However, if the pressure of the bubbler or the flow rate of the mass flow controller is controlled according to the following equation (4) for calculating the accurate supply amount of the organic metal without using the approximation, the organic metal supply device with a stable supply amount, and It is clear that a metal organic chemical vapor deposition apparatus with a stable supply ratio can be constructed.

[0036]

(Equation 4) (4)

[0037]

According to the organic metal supply apparatus of the present invention,
Means for measuring the partial pressure of the organometallic gas in the mixed gas in which the organometallic gas is mixed, and the pressure P _B in the bubbler based on the means.
Is provided to maintain P _s / P _B constant, so that the organic metal supply amount [s] can be kept constant. Furthermore, comprising means for maintaining the means for measuring the partial pressure of the organic metal gas in the mixed gas of the organic metal gases are mixed, the lP _s by adjusting the flow rate l of the carrier gas flowing into the bubbler it back constant Therefore, there is an effect that the supply amount [s] of the organic metal can be kept constant.

In the organometallic vapor phase epitaxy apparatus of the present invention, the partial pressure of each source gas in the gas flowing into the reaction tube is measured, and each of the organometallic supply apparatuses is controlled so that the ratio of the partial pressures becomes constant. Since the supply amount is controlled, there is an effect that the supply ratio of each organic metal becomes stable.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a first embodiment of the present invention.

FIG. 2 is a diagram illustrating a second embodiment of the present invention.

FIG. 3 is a diagram illustrating a third embodiment of the present invention.

FIG. 4 is a diagram for explaining a fourth embodiment of the present invention.

FIG. 5 is a diagram illustrating a fifth embodiment of the present invention.

FIG. 6 is a diagram illustrating a metal organic chemical vapor deposition apparatus in which a capillary is inserted near a substrate.

FIG. 7 is a diagram illustrating a conventional organic metal supply device.

FIG. 8 is a diagram illustrating another conventional organic metal supply device.

FIG. 9 is a diagram illustrating a conventional metal organic chemical vapor deposition apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1, 11 Conventional organic metal supply apparatus 2 Organic metal raw material 3 Bubbler 4 Constant temperature bath 5 Mass flow controller 6 Diaphragm type pressure gauge 7 Control valve 8 Pressure control apparatus 9a, 9b, 9c Air valve 12a, 12b Cylinder 13a, 13b Mass flow controller 14 Piping 15 Reaction tube 21, 31, 41 Organometallic supply device according to the present invention 22, 42 Control device 23, 43 Partial pressure measuring device 52 Piping 54 Reaction tube 55 Partial pressure measuring device 56 Control device 61 Reaction tube (inner tube) 62 Substrate 63 susceptor 64 capillary

Continuation of front page (56) References JP-A-62-256424 (JP, A) JP-A-4-362176 (JP, A) JP-A-6-145992 (JP, A) JP-A-6-295862 (JP JP-A-2-43721 (JP, A) JP-A-1-255214 (JP, A) JP-A-1-96922 (JP, A) JP-A-4-78131 (JP, A) JP-A-6-97081 (JP, A) JP-A-1-96922 (JP, A) JP-A-1-255214 (JP, A) JP-A-2-43721 (JP, A) A) (58) Field surveyed (Int. Cl. ⁷ , DB name) H01L 21/205 C23C 16/44

Claims (4)

(57) [Claims] 1. A chromatic supplying organometallic gases by a carrier gas is bubbled in the a bubbler while maintaining the pressure in the bubbler containing the organometallic to a predetermined value
Metal-containing gas supply means , downstream of the bubbler
In the organic metal delivery system having a partial pressure detecting means for detecting the partial pressure of the organometallic gas of the organic metal-containing gas (P _S), the organometallic-containing gas by a signal from the partial pressure detecting means
Controlling the pressure (P _B ) in the bubbler in the gas supply means to control the partial pressure of the organometallic gas in the organometallic-containing gas and the bubbler.
An organic metal supply device comprising means for maintaining a constant pressure ratio (P _S / P _B ) to the internal pressure . 2. The apparatus according to claim 2, wherein said partial pressure detecting means is an ultrasonic cell or a four- cell type.
The organic metal supply apparatus according to claim 1, wherein the organic metal supply apparatus is a quadrupole mass analyzer . 3. A plurality of organic metal-containing gas supply means for supplying the organic metal gas by bubbling a carrier gas in the bubbler while maintaining the pressure in the bubbler containing the organic metal at a predetermined value. , The plurality
The organic metal-containing supplied from the organometallic-containing gas supply means
An organometallic gaseous phase comprising: a pipe for merging gases and transporting the gas to a reaction tube; and a partial pressure detecting means attached to the pipe and detecting partial pressures of a plurality of organic metal gases contained in the mixed organic metal-containing gas. In the growth apparatus, by adjusting the pressure in the bubbler containing the corresponding organometallic in accordance with the partial pressure of each organometallic gas in the mixed organometallic-containing gas , each of the bubbles from each bubbler is adjusted.
An organometallic vapor phase epitaxy apparatus comprising means for controlling the supply amount of organometallic. 4. The metalorganic vapor phase epitaxy apparatus according to claim 3, wherein said partial pressure detecting means is a quadrupole mass analyzer.