JPH0226017A - Method of producing saturated vapor of organometal compound in organometallic vapor growth - Google Patents

Abstract

PURPOSE:To facilitate control of the composition of a single crystal thin film by a method wherein an inner tube which is directly connected to an exhaust outlet and has a disperser at its bottom is inserted into a cylinder and both the cylinder and the inner tube are filled with organometal compound and carrier gas introduced into the cylinder through an introducing inlet is discharged out of the cylinder. CONSTITUTION:An introducing inlet and an exhaust outlet for carrier gas are provided in the upper part A2 of a cylinder A and an inner tube G directly connected to the exhaust outlet is inserted into the cylinder A. Both the cylinder A and the inner tube G are filled with an organometallic compound and the carrier gas is introduced into the cylinder A through the introducing inlet and discharged out of the cylinder A from the bottom of the inner tube G and through the inner tube G. Therefore, a constant supply rate of the organometallic compound can be obtained stably for a long time without relying upon the filling rate of the solid organometal compound, the flow rate of the carrier gas and so forth. With this constitution, the composition of a single crystal thin film can be controlled.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to metal organic chemical vapor phase epitaxy of solid organometallic compounds for semiconductors.
VaporDeposition: )10-CVD
) method for producing saturated vapor of organometallic compounds.

[Conventional technology]

Currently, organometallic compounds are used as a method that can be efficiently mass-produced in the production of semiconductor lasers, etc.) 10-CV
D method is well known.

In the No-CVD method, an organometallic compound is brought into contact with a carrier gas such as hydrogen gas, and the saturated vapor of the organometallic compound is sent onto a wafer under high temperature, and is reacted with the raw material gas on the wafer. This is a method of growing a single crystal thin film of a compound produced by. More specifically, for example, (CI-13) sGa and As are placed on the kneebar.
) 13 gases are reacted on a wafer under high temperature,
The following reaction formula △ (CH3)3 Ga+ASH:+ -m=-→GaA
The method is to grow a GaAS single crystal thin film using s+30H4.

) In the 10-CVD method, an organometallic compound filled in a cylinder is transported to a reactor using a carrier gas to grow crystals.

As previously disclosed in Japanese Patent Application Laid-Open No. 63-11598, the present inventors constructed a carrier-gas inlet pipe (1) as shown in FIG.
) A disperser (filter) (4
), and the lower part (2-1) of the cylinder (2) has a narrower inner diameter than the upper part of the cylinder (2-2), and an inclined part (2-3) is attached above the narrowed part. from the introduction pipe (3) to the cylinder (2) via the disperser (4)
The carrier gas introduced into the bottom of the cylinder (2) becomes saturated with the vapor of the organometallic compound while rising inside the cylinder (2) filled with the organometallic compound, and is discharged from the cylinder through the outlet (5). -We proposed a cylinder for CVD method.

Although this proposal is particularly effective in the case of solid organometallic compounds, it has been found that it is still insufficient.

[Problem to be solved by the invention]

In the above proposal, trimethylindium (TMIn> is used as the organometallic compound, and the amount of TMIn supplied is determined by discontinuously changing the filling amount between 5 and 50 g.

According to this method, the filling state of TMIn at the start of the supply test for each TMIn amount is extremely good, and unlike the proposed embodiment, the carrier gas flow rate is not large and the supply test is completed within a relatively short time of 3 hours. Time TM I
Since the filling state of n hardly changes, TM during the test
The contact between In and the carrier gas is sufficient so that
Saturation was easily reached, and as a result, the supply amount remained constant.

However, when we conduct a supply test in accordance with actual usage, that is, fill a cylinder with a predetermined amount of TM In and conduct a supply test continuously over a long period of time, we find that the filled state does not reach the filled state in a relatively short period of time, as mentioned earlier. Although almost no change is observed, as time passes, the TM I n around the filter becomes hollow and a gas flow path is formed, so the contact between the TM I n and the carrier gas gradually becomes insufficient, and as a result, the supply amount gradually decreases. The disadvantage of this study was that it was difficult to control the composition of single-crystal thin films.

(Means for Solving the Problems) Therefore, in order to further improve the problem, the inventor of the present invention conducted various studies and established an inlet and an outlet for the carrier gas at the top of the cylinder, respectively, and inserted an inner pipe directly connected to the outlet into the cylinder. By inserting the cylinder and filling both the cylinder and the inner tube with an organometallic compound, the carrier gas is introduced into the cylinder from the above-mentioned inlet, passes through the inner tube from the bottom of the inner tube, and is discharged from the outlet. The present inventors have discovered that extremely good results can be obtained even when the carrier gas flow rate is large, and have completed the present invention.

That is, the gist of the present invention is to provide an inlet and an outlet for carrier gas at the top of a cylinder for organometallic vapor phase growth, and to provide an inner tube directly connected to the outlet and equipped with a disperser at the bottom. The carrier gas is inserted into the cylinder, filled with an organometallic compound in both the cylinder and the inner tube, and is fed into the cylinder from the inlet. The present invention provides a method for producing saturated vapor of an organometallic compound in an organometallic vapor phase epitaxy method, which is characterized by discharging the vapor from the cylinder through the above-mentioned outlet, thereby achieving the intended purpose.

The disperser used in the present invention may be any porous material, such as a plastic ball filter or a cell ball disk, or may be made of stainless steel or ceramics, or may be made of fibrous material. Even if it is durable, it is uniform 1~1
A fine porous material with a diameter of 00 μm is sufficient.

[For production]

The cylinder disclosed by the present inventors in JP-A No. 63-11598 was explained with reference to FIG. 3, and TMIn was placed in this cylinder made of glass, and nitrogen gas was continuously introduced at a rate of 500 id per minute. Then, TM
When the amount of In used was about 10%, cavitation of TMI n was observed around the filter and the amount supplied began to decrease.

As a result of various tests, it has been found that when tested using the method of the present invention, a uniform amount of gas can be obtained satisfactorily over a long period of time, thereby producing a desired single crystal thin film on a wafer. This is thought to be due to the action of TM I n, which fills the inner tube, supplementing the terminal chain fraction. In this case, the linear velocity of the carrier gas in the cylinder is preferably as slow as possible, but there is no particular limitation, and it is desirable to determine the diameter of the cylinder in accordance with the flow rate of the carrier gas. In addition, considering the ease of filling the solid organometallic compound with respect to the inner tube, it is generally appropriate that the diameter thereof is 5J11111 or more, although it depends on the size of the cylinder. Note that the lower part of the cylinder may be a narrow diameter part whose inner diameter is narrower than that of the upper part of the cylinder, and there is no problem even if an inclined part is provided above the narrow diameter part.

Furthermore, the entire cylinder is not limited to a round shape.

〔Example〕

1 and 2 show cylinders for organometallic vapor phase growth used in the method of the present invention.
) and a pipe (B) vertically rising above the inlet for organometallic compounds for charging the organometallic compound into the inner pipe (G). Each metal compound inlet (C) is provided, and a carrier-gas inlet (D) is provided on the circular periphery of the inlet, and the carrier-gas inlet (D) rises vertically above the carrier-gas inlet.
Carrier gas is introduced into the cylinder (A) from D) via the cock (E). An inner pipe (G) for filling the organometallic compound is directly connected to the latter organometallic compound inlet (C), and is inserted through the center of the cylinder (A) from the top to near the bottom. At the lower end of (G) is a disperser (filter > [NUPROFILTER100
μ (Nupro Filter) (Nupro Company: 4
800 East 345 Street, Willaukbai, Ohio 44094 4800 East 34
5th Street, Willonohby, 0h
io 44094)] (H) is provided. The latter organometallic compound input port (C) also serves as a carrier gas discharge port, and there is a carrier gas discharge pipe (F) that bends from the top of the cylinder (^) to its circular periphery and then rises vertically. is connected to discharge a carrier gas containing saturated vapor of an organometallic compound via a cock (I). Then, the pipe (D) is connected via the cock (E).
The carrier gas is introduced into the cylinder (A) filled with the organometallic compound as shown by the arrow and reaches the bottom of the cylinder (A), during which time the vapor of the organometallic compound is released. The loaded carrier gas then passes through the disperser (H) and rises in the inner tube (G) also filled with the organometallic compound, as indicated by the arrow, where it is filled with the saturated vapor of the organometallic compound and passes through the exhaust pipe. via Road (F) to Kok (I)
).

In this cylinder (A), its lower part (A1) is the upper part (
This is a narrow diameter portion whose inner diameter is narrower than A2), and the inner diameter of this narrow diameter portion (A1) is set to about 1.1 times the diameter of the inner tube (G). Above this narrow diameter part is an inclined part (A3
) is subsequently provided, the slope (A3) continuing into the upper part of the cylinder (A2).

The angle of inclination of the inclined portion (A3) is appropriately set within the range of 0° to 50''.

Therefore, as shown in Fig. 4, this cylinder (A) (cylinder diameter 7511111, inner pipe diameter 20III11
) and the inner tube (G) were filled with 57.9 g of TM In (of which 15.3 g was in the inner tube), and the hydrogen gas was immersed in a constant temperature bath (J) at 20°C with a flow rate controller (in). The line (S) was connected to the carrier gas introduction conduit (D), and hydrogen gas was continuously introduced at a rate of 500 ml per minute for 8 hours to exhaust the TM I n gas.

TMInl in the hydrogen gas was collected with a liquid nitrogen trap (H) and measured from the change in weight. After the measurement, hydrogen gas was supplied again at the same flow rate and for the same period of time, and this operation was repeated until the total amount of TMin used reached nearly 80% of the filling amount. The measurement results are shown in Figure 5.

TMIn supply on the vertical axis in Figure 5! (g/Hr) is TM
It means the amount of TMIn gas generated by bringing In into contact with a carrier gas.

[Conventional example]

Using the cylinder shown in Figure 3, TM I n57-2
g was filled into the cylinder (2), and hydrogen gas was flowed at a rate of 500 m/min as in the example. TM in hydrogen gas
In was collected using the same method as in the example, and the change in supply amount over time was measured. In this case, the supply amount decreased as the cavity expanded. The results are shown in Figure 5.

(Effects of the Invention) According to the method of the present invention, compared to conventional methods, the supply amount of the organometallic compound is stable for a long time without depending on the filling amount of the solid organometallic compound, the flow rate of the carrier gas, etc. Therefore, it is possible to control the composition of single crystal thin films, which has great industrial value.

[Brief explanation of the drawing]

Fig. 1 is an explanatory front view of a cylinder for vapor phase growth of deposited metals used in the method of the present invention, Fig. 2 is an explanatory plan view of the same cylinder, Fig. 3 is an explanatory front view of a conventional cylinder, and Fig. 4 1 is a systematic explanatory diagram of a test device incorporating the cylinder shown in FIG. 1, and FIG. 5 is a chart showing the results of a comparative test between the cylinder of the present invention example and the cylinder of the conventional example conducted using the test device of FIG. 4. It is. A Cylinder Lower part of the cylinder (narrow diameter part) Slanted part of the upper part of the cylinder Organometallic compound inlet pipe Organometallic compound inlet Carrier - Gas inlet pipe Cock carrier - Gas discharge pipe Inner pipe Distributor (filter) Pressure adjustment Flow Controller Thermostat Liquid Nitrogen Trap Diagram 2 Procedure Amendment (Voluntary) Contents of Amendment August 23, 1988

Claims (2)

[Claims] (1) An inlet and an outlet for carrier gas are provided at the top of a cylinder for organometallic vapor phase growth, and an inner tube directly connected to the outlet and equipped with a disperser at the bottom is inserted into the cylinder, Both the cylinder and the inner tube are filled with an organometallic compound, and the carrier gas is fed into the cylinder from the inlet port, from the bottom of the cylinder, through the above-mentioned disperser, through the inner tube, and from the outlet port. A method for generating saturated vapor of an organometallic compound in an organometallic vapor phase epitaxy method, which is characterized by discharging the vapor outside the cylinder. (2) A method for generating saturated vapor of an organometallic compound in an organometallic vapor phase epitaxy method, characterized in that the cylinder has a vertical cylindrical shape with an inner diameter narrower at the lower part than at the upper part.