JPS60131973A - Method for vaporizing organometallic compound - Google Patents

Abstract

PURPOSE:To feed a uniformly vaporized organometallic compound to a growing reaction furnace with high controllability by attaching a bubble forming jig having spouting holes to the tip of a gas spouting part to make bubbles fine when an organometallic compound is bubbled. CONSTITUTION:A bubble forming jig 12 having plural gas spouting holes 13 is attached to the tip of the spouting part 4a of a guide 4 for guiding a gas for bubbling to a position under the surface 6 of a liq. The jig 12 is in the form of a trumpet or the like, and it is made to act as a control plate by gradually increasing the diameters of the holes 13 in the radial direction. The density of the holes 13 may be increased. A gas sent from the guide 4 is converted into fine and uniform bubbles 14 by spouting from the holes 13, and a uniformly vaporized organometallic compound can be fed to the outside with high controllability.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an organic metal vaporization method that can efficiently and controllably obtain a good growth layer of a compound semiconductor using an organic metal.

Configuration of conventional example and its problemsM
V D (Metatorganic Chemica)
As a crystal growth method for compound semiconductors, the VaporDeposition method is superior to conventional liquid phase growth methods in terms of mass production and high-precision control for the production of new functional devices with thin film microstructures. MtMB
/ Widely used in the development of Ga-S-based semiconductor lasers.

In this MOCVD method, for example, when growing an m-v compound semiconductor layer, an organic metal is generally used as the Group I element, and a hydride is used as the Group V element. The method of supplying this 41 metal to the growth reactor is to introduce a carrier gas into the liquefied organic metal, and by bubbling it, molecules approximately corresponding to the saturated vapor pressure at a set temperature are converted into gas. It is sent to the growth reactor.

FIG. 1 shows the structure of an organometallic bug ring bomb currently used in MOCvD growth. A liquefied organic metal (for example, triethyl indium) 2 is placed in a stainless steel cylinder 1, and a cicarious gas (for example, H2) is introduced through an inlet 3. The introduced carrier gas passes through the guide 4 from the lower end spouting part 4a of the guide 4 into bubbles 5.
comes out and rises in the organic metal 2 in the cylinder 1, reaches the liquid level 6, the bubbles 6 burst, and the vapor pressure corresponds to the saturated vapor pressure at the set temperature in the cavity 7 above the liquid level in the cylinder 1. The organometallic gas molecules are pushed away by the volume of the bubble 6, and strike! It is pushed out through the J-T jig 8 to the outlet 9 and sent to the growth furnace. Note that the pulp 10 is for ON-OFF of the flow of carrier gas. The blind screw 11 is the opening for introducing the organic metal into the cylinder 1.

In this method, when the organic metal 2 is sufficiently grooved in the cylinder 1, the cavity 7 is narrow, so the liquid level 6 shakes violently due to the bursting of the large bubble 6 coming out from the tip of the guide 4. There is a considerable amount of organometallic material flowing out to the outlet from the outlet 9, etc., and it becomes impossible to control the supply amount of constituent elements of the growth layer by the flow rate of the bubbling gas. As usage increases and the liquid level 6 drops, the danger is high.

The supply pipe after the outlet is often kept at room temperature, and organic metals, which have a low vapor pressure at room temperature, remain accumulated for a particularly long period of time. This is because the bubbles 5 are still large. Also, in order to alleviate this problem, it is conceivable that a plurality of holes are provided at the lower end of the guide 4, but since the guide 4 has a straight shape, air bubbles are generated only from the hole near the top of the holes provided at the lower end. And it's inefficient.

MOCVD growth is determined by the rate of supply of group I elements, and since organic metals are mostly group Iv elements, there are problems with conventional organic metal vaporization methods using cylinders in terms of growth rate control or composition control of mixed crystal semiconductors. many.

OBJECTS OF THE INVENTION An object of the present invention is to provide a method for vaporizing an organometallic material in which the bubbles of a carrier gas can be reduced in bubbling of an organometallic material and the organometallic material can be supplied to a growth reactor system in a well-controlled manner.

Structure of the Invention The present invention involves bagging a liquefied organic metal using a gas, and when the liquefied metal is gasified, the gas is introduced below the liquid surface. A bubble forming jig is provided and used to vaporize the organic metal. In other words, the present invention takes the above points into consideration, and the bubble forming jig is, for example, shaped like a square, and the diameter of the small hole is the same or becomes slightly larger as it moves away from the center of the guide. The open control plate is used to reduce the size of the bubbles, so that small bubbles are uniformly formed within the cylinder, and as a result, the organic metal is provided to the growth reaction system in a well-controlled manner.

DESCRIPTION OF THE EMBODIMENTS FIG. 2 shows the tip of a bubble generating section according to an embodiment of the present invention. Components that are the same as those in FIG. 1 are indicated by the same symbols. The bubble forming jig 12 located immediately behind the tip ejection part 4a of the guide 4 has a square shape, and a plurality of gas ejection holes 13 are provided therein. This hole 13 is for the purpose of converting the gas sent from the guide 4 into fine bubbles 14.
In order to maintain uniformity in the amount of pores 4, it is preferable that the diameter of the pores becomes larger or the density of the pores increases as the distance from the center increases. Of course, it is sufficient to simply provide a hole of an appropriate size. If a large amount of gas is sent, it may leak from the bottom 15 of the bubble forming jig 12, so
6 is better closed.

Even when gas is flowed in this structure, the bubbles 14 are formed finely and uniformly, and the liquefied organometallic is less likely to scatter due to the cracking of the bubbles 14 at the liquid level 6, so that stable and uniform vaporized organometallic is produced. It can be sent to the next growth system.

FIG. 3 shows another embodiment of the invention. In this case, the gas is fed through the same guide 4 as in the prior art, and large bubbles 6 are generated from the jetting portion 4a at the tip of the guide.

A bubble control plate 16 is installed on top of this, and small bubbles 14 are uniformly formed through countless small holes 17 provided therein. This produces an effect similar to that of the previous embodiment. The gap between the cylinder 1 and the control plate 16 needs to be made as small as possible since it is not good if large bubbles are generated from the gap. Also, this control plate 16 has small air bubbles 14.
In terms of formation, a plurality of sheets may be provided.

FIG. 4 shows yet another embodiment. This is because the bubble forming jig 12 placed immediately after the distal end jetting part 41L of the guide is made of a porous material.

By using this, countless small bubbles 14 are formed through countless small holes 18, and there is no large fluctuation in the liquid level e, so that the vaporized organic metal can be efficiently and smoothly delivered to the outside of the cylinder. I can do it.

In these embodiments, the guide 4 and the bubble forming jig 12
Although the guide 4 and the control plate 16 have been described as separate parts, the guide 4 and the jig may of course be formed integrally. As an example of integration, a guide 4 with the same diameter as the guide 4 has multiple holes, and a 5-shaped connection is made at the lower end spout 4a of the guide 4.The guide 4 is made longer and has multiple holes near the lower end jet The same effect can be obtained even if the lower end spout portion 4a is closed and bent into a five-shape shape.

As is clear from the above examples, when obtaining a vaporized organometal by bubbling gas through the liquefied organometal, the bubbles of the bubbling are made small and uniform to suppress fluctuations in the liquid level of the liquefied organometal. An amount of vaporized organic metal can be obtained in proportion to the flow rate of the bugling gas, and there is no liquid splashing out as in the conventional method, resulting in extremely good controllability.

Normally, the flow rate of the organic metal used in MOCVD growth is about 1d-5 to 1V7 miyr, but by using the present invention, control on this order can be relatively easily performed. 6. The shape of the bubble forming jig in the example, the shape of the control plate, and the shape of the holes. Although the size and shape of the cylinder do not matter, the filling rate of the liquefied organic metal in the cylinder should be around 70 to 80%, and the cylinder should have a sufficient cavity above the liquid level. Furthermore, the effects of the present invention are even greater.

Effects of the Invention As described above, the present invention makes it possible to supply vaporized organic metals to the outside with good control by reducing the diameter of bubbles caused by bugling of liquefied organic metals and making the density uniform. Mixed crystal compound semiconductor (
In1-xG-cho-8yP1-y.

(Mut, G&1-Jc)yIn, -yP, etc.) can be controlled relatively easily.

The MoCVD method, which is a crystal growth method using the present invention, is a growth method with great potential for mass production of compound semiconductors, and the present invention can also be used to control impurity doping of organic metals, which is useful in the semiconductor device manufacturing field. Its industrial value is extremely high.

[Brief explanation of drawings]

Figure 1 is a schematic structural diagram of the conventional organic metal vaporization method, Figure 2
3 and 4 are structural diagrams of a bubble generating section used in the vaporization method of the embodiment of the present invention. 4... Gas guide, 41L... Lower end spouting part, 6... Liquid level, 7... Cavity part,
12...Bubble forming jig, 13.17. j9...
...Blowout hole, 16...Control board. Name of agent: Patent attorney Toshio Nakao and 1 other person
1 Figure fo Figure 2 N Figure 3 Figure 4・

Claims (1)

[Scope of Claims] (1) Bubbling the liquefied organometallic with gas, and when gasifying the liquefied organometal, the tip of the gas spouting part of the guide that guides the gas below the liquid surface. A method for vaporizing organic metals, comprising: providing a bubble forming jig having a plurality of the gas ejection holes, and ejecting the gas from the ejection holes. (2) The organic metal vaporization method according to claim 1, wherein the jig is a control plate having a plurality of holes at the upper part of the ejection part of the guide for introducing the gas. (3) The method for vaporizing an organic metal according to claim 1, characterized in that the jig has an open-shape shape and the diameter of the ejection hole is the same but increases as the distance from the center of the guide increases. . (6) The method for vaporizing an organic metal according to claim 3, characterized in that the density of the ejection holes provided in the bubble forming jig increases as the distance from the center increases. The organic metal vaporization method according to claim 1, characterized in that the material is porous. (6) The guide and the bubble forming jig are integrated. A method for vaporizing an organic metal according to claim 1.