JPH04131934U - MOCVD equipment - Google Patents

Abstract

(57) [Summary] [Purpose] To provide an MOCVD apparatus that can stably supply a raw material gas while suppressing the temperature of the raw material to a certain value or less even when the pressure inside the raw material container is lower than the pressure inside the reaction chamber. [Structure] An ejector 20 is provided in the channel for supplying the raw material gas to the reaction chamber 3, using a carrier gas as a driving gas to suck the raw material gas evaporated and drawn out in the raw material container 1. It should be aspirated and entrained in the carrier gas.

Description

[Detailed explanation of the idea]

0001

[Industrial application field]

This invention equates liquid or solid raw material vapor (raw material gas) with carrier gas. MOCVD method (MOCVD method) in which a thin film is formed on the substrate by supplying the same to the substrate in the reaction chamber. The present invention relates to an MOCVD apparatus that performs a metal organic chemical vapor deposition method.

0002

[Conventional technology]

In the MOCVD method, an organic metal is used as a raw material, and the vapor of the organic metal is used as a carrier. It is supplied into the reaction chamber along with Yagas. In such MOCVD method When using a solid organic metal as a raw material, the solid raw material is usually kept in a thermostatic container. At the same time, a carrier gas is introduced into the container to heat and evaporate the key. The raw material gas is made to accompany the carrier gas. In addition, in the case of liquid raw materials , and entrain it by bubbling it with carrier gas.

0003 However, with the method of introducing a carrier gas into a container containing solid raw materials, In order to entrain the raw material gas with the carrier gas, the flow rate of the carrier gas is slowed down. This increases the diameter of the piping system and increases the size of the equipment, which is an inconvenience. There was a coincidence.

0004 On the other hand, even if the concentration is not saturated, it is fine as long as the concentration of the raw material in the raw material gas is constant. , when the flow rate of the carrier gas is increased, the raw material cannot evaporate in time, and as shown in Fig. 2 As shown in , the concentration of the raw material gas decreases as the flow rate of the raw material gas increases. There was an inconvenience.

[0005] In addition, in the case of liquid raw materials, as the liquid level decreases as the liquid raw materials are consumed, the raw material gas The amount of gas entrained will change.

[0006] Therefore, as shown in Figure 3, the raw material gas evaporated only by the vapor pressure of the raw material is , an MOCV configured to be supplied to the reaction chamber entrained with a desired amount of carrier gas. D device has been proposed. Note that two raw material supply systems are shown here. , the raw material supply method is the same for both systems, only the type and flow rate of the raw material are different. The description will be given using the same reference numerals.

[0007] In the figure, 1 is a raw material container housed in a constant temperature bath 2, 3 is a reaction chamber, and 3 is a reaction chamber. A substrate P is provided inside. The pressure inside the reaction chamber 3 is usually reduced by a vacuum pump 4. condition or maintained at normal pressure.

[0008] The solid raw material G in the raw material container 1 is heated to a predetermined temperature depending on the type and amount of raw material supplied. It evaporates and becomes a saturated raw material gas. This raw material gas is led out from valve 5. , after being controlled to a predetermined flow rate by a mass flow controller (MFC), pipe 6, MF It is mixed with a predetermined amount of carrier gas supplied via C, and is the same as the carrier gas. The gas is then introduced into the reaction chamber 3 via the switching valve 7 and the raw material gas supply pipe 8.

[0009] In addition, the piping route from the raw material container 1 to the mixing point with the carrier gas is also connected to the MFC. Keep the raw material at a temperature higher than the heating temperature, including the raw material, to prevent the raw material gas from condensing in the piping route. I have to. Further, a concentration adjusting gas is supplied from the pipe 9, and an exhaust gas is supplied from the pipe 10. Raw material gases of other systems are supplied from the pipes 11, respectively.

0010 According to the above configuration, the solid raw material is always entrained in the carrier gas in a saturated vapor state. Therefore, if the raw material gas amount and carrier gas amount are determined by MFC, the raw material with the desired concentration can be obtained. A feed gas can be supplied to the reaction chamber 3.

[0011]

[Problem that the idea aims to solve]

In the case of the above device, if the pressure inside the reaction chamber 3 is lower than the pressure of the raw material gas, the raw material gas The gas is stably entrained in the carrier gas and supplied into the reaction chamber 3. However, good In order to obtain a thin film of good quality, the pressure inside the reaction chamber 3 may be set high; In this case, the pressure inside the reaction chamber is almost equal to or higher than the pressure inside the raw material container. , the pressure of the carrier gas must also be increased, which increases the total partial pressure of the raw materials. There is an inconvenience that the raw material gas is not sufficiently entrained by the carrier gas due to physical deterioration. arise.

0012 To prevent this, there is a method of increasing the heating temperature of the raw materials and increasing the vapor pressure of the raw materials. It is possible, but if you raise the temperature of the raw material, there is a risk that the raw material itself will thermally decompose. be. Also, due to the structure, the temperature up to the point where it is mixed with the carrier gas is kept at a temperature higher than that of the raw material. This causes the MFC to exceed its operating temperature limit and the MFC to function normally. There was a problem in that the system did not operate properly, making it impossible to stably supply raw materials.

[0013] This invention solves the above problems and allows the pressure inside the raw material container to be lower than the pressure inside the reaction chamber. It is possible to stably supply raw material gas while keeping the temperature of the raw material below a certain value. The aim is to provide a MOCVD device that can

[0014]

[Means to solve the problem]

In order to achieve the above object, the MOCVD apparatus of the present invention communicates with the reaction chamber. An ejector is provided in the flow path to suck the raw material gas using a carrier gas as a driving gas. It is characterized by the fact that it has been established.

[0015]

[Effect]

According to the above configuration, the raw material gas is sucked into the carrier gas by the ejector. Even when the pressure of the raw material gas is lower than that of the reaction chamber, it can be stably supplied to the reaction chamber. I can do it.

[0016]

【Example】

Hereinafter, one embodiment of the present invention will be described based on FIG. 1. In addition, as shown in Figure 3 above, Elements that are the same as those of the conventional device will be given the same reference numerals and detailed explanations will be omitted.

[0017] It evaporates due to the heating in the constant temperature bath 2, and flows from the raw material container 1 due to the vapor pressure of the raw material itself. The raw material gas to be discharged is led out through the valve 5 as in the conventional case, and the flow rate is controlled by the MFC. It will be done. This raw material gas is mixed with carrier gas supplied via pipe 6 and MFC. It is sucked by the ejector 20 installed at the junction point, mixes with the carrier gas, and is cut. The gas is introduced into the reaction chamber 3 via a replacement valve 7 and a raw material gas supply pipe 8 .

[0018] The ejector 20 ejects carrier gas, which is a driving gas, from a jet nozzle. The area around the nozzle is reduced in pressure, thereby sucking the raw material gas from the suction pipe. A widely used ejector can be used. It is Noh.

[0019] At this time, the reaction is performed by controlling the vacuum pump 4 or without providing the vacuum pump 4. The pressure in the reaction chamber 3 is set high, and the pressure of the raw material gas flowing out from the raw material container 1 is Even if the pressure in the reaction chamber 3 is lower than the pressure in the reaction chamber 3, the raw material gas is The mixed raw material gas is sucked in by the ejector 20 with a high pressure and has a higher pressure than the pressure inside the reaction chamber 3. become.

[0020] Therefore, there is no need to raise the temperature of the raw material to increase its vapor pressure. , regardless of the pressure inside the reaction chamber 3, the heating temperature of the raw material container 1, that is, the temperature of the raw material It can be kept below a certain value. Also, when liquid materials are used as raw materials, , into the raw material container 1 in the same manner as above without bubbling with carrier gas. This can be done by storing it and heating it to evaporate it.

[0021] Note that the configuration of the MOCVD apparatus is limited to that described in the above example. Rather, the present invention can be applied to MOCVD apparatuses with various configurations.

[0022]

[Effect of the idea]

As explained above, according to the MOCVD apparatus of the present invention, the pressure inside the raw material container is Even when the pressure is lower than the reaction chamber pressure, raw material gas can be stably supplied without raising the raw material temperature. You will be able to do it. Additionally, the ejector has no mechanically moving parts, so friction No particles are generated and there is no adverse effect on the thin film.

[0023] In addition, by using an ejector, pressure changes on the ejector outlet side can be Since the pressure is not transmitted to the container side, pressure fluctuations occur on the reaction chamber side due to switching of valves, etc. Even if a A uniform thin film can be produced.

[Brief explanation of drawings]

FIG. 1 is a system diagram showing an embodiment of the MOCVD apparatus of the present invention.

FIG. 2 is a diagram showing the relationship between carrier gas flow rate and raw material concentration in a conventional MOCVD apparatus.

FIG. 3 is a system diagram showing an example of a conventional MOCVD apparatus.

[Explanation of symbols]

1... Raw material container 2... Constant temperature chamber 3... Reaction chamber 4... Decompression pump 8... Raw material gas supply pipe 20... Ejector MFC... Mass flow controller P... Board

Claims (1)

[Scope of utility model registration request] 1. In an MOCVD apparatus configured to supply a raw material gas evaporated only by the vapor pressure of a liquid or solid raw material to a reaction chamber along with a carrier gas, a flow path communicating with the reaction chamber includes: An MOCVD apparatus comprising an ejector that sucks the raw material gas using a carrier gas as a driving gas.