JPS6296391A - Gas supplier for vapor-phase growth - Google Patents

Abstract

PURPOSE:In the gas feeder for vapor-phase crystal growth, the path for feeding the carrier gas to the bubbler tank is equipped with a heater whereby the flow rate of the starting vapors are made controllable according to prescribed values despite no increase in gas flow rate of the carrier gas. CONSTITUTION:In the gas feeder for vapor-phase crystal growth, the carrier gas is fed through the controller 1 into the bubbler tank 10 to evaporate the starting liquid material 11 and the resultant mixed gas of the material vapors and the carrier gas is passed through the controller 1, then fed into the reaction oven. Further, the feeding path for the carrier gas to the bubbler tank 10 is equipped with a heater 12. Since the heated carrier gas can compensate the temperature drop of the starting liquid material 11 caused by the vaporization of the liquid in the bubbler tank 10, the object described above can be attained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to an improvement in a gas supply device for vapor phase growth that controls and supplies source gas to a reactor of a vapor phase growth device in the manufacturing process of semiconductor devices and the like.

[Technical background of the invention]

BACKGROUND ART The amount of raw material gas to be supplied must be adjusted and supplied to the reactor of a vapor phase growth apparatus used in the manufacturing process of semiconductor devices and the like. Conventionally, as a gas supply apparatus for vapor phase growth, one shown in FIG. 2 has been used.

In Figure 2, the controller (indicated by a broken line in the figure) 1
is arranged between the bubbler tank 10 and a carrier gas supply section (not shown) and a reactor of the vapor phase growth apparatus. A carrier gas such as hydrogen or argon is supplied to the bubbler tank 10 through a mass flow sensor 2, a thermal valve 3, and a ratio detector 4 in the controller 1. A raw material liquid 11 such as silicon halide contained in the bubbler tank 10 is evaporated by bubbling of the carrier gas. Then, the mixed gas of the raw material gas and the carrier gas passes through the ratio detector 4 in the controller 1 and is supplied to the reactor of the vapor phase growth apparatus (not shown).

In this gas phase growth gas supply device, the flow rate of the source gas is controlled by adjusting the amount of carrier gas supplied to the bubbler tank 10. That is, the mass flow sensor 2 detects the flow rate of the carrier gas. Further, when the mixed gas flows through the geodetector 4 described above, the concentration of the raw material gas is detected based on the difference in thermal conductivity between the carrier gas and the raw material gas. These signals are sent to the calculation circuit 5, and the flow rate of the raw material gas to the reactor is calculated. The calculated raw material gas flow rate signal is sent to the control circuit 6 and compared with a setting signal input from the outside. and,
By adjusting the flow rate of the carrier gas with the thermal valve 3 until there is no difference between the two, and adjusting the amount of evaporation of the raw material gas in the bubbler tank 10, the flow rate of the raw material gas to the reactor can be adjusted to the set value. control.

[Problems with background technology]

In the conventional vapor phase growth gas supply apparatus described above, if the raw material gas is continuously supplied for a long time, the carrier gas a
However, there was a drawback that the flow rate of the raw material gas could not be controlled to a set value unless the amount was gradually increased.

As a result of various studies on the cause of this, the inventors of the present invention found that the temperature of the raw material liquid 11 in the bubbler tank 10 was a problem. That is, if the raw material gas is continuously supplied for a long time, the raw material liquid 11 in the bubbler tank 10
Since the heat of vaporization is removed from the surface of the raw material liquid 11, the temperature of the raw material liquid 11 gradually decreases. For this reason, the amount of evaporation of the raw material gas tends to gradually decrease, and in order to control the flow rate of the raw material gas to the reactor according to the set value, the flow rate of the carrier gas must be increased.

[Purpose of the invention]

The present invention has been made in order to eliminate the above-mentioned drawbacks, and aims to provide a gas supply device for vapor phase growth that can control the flow rate of source gas to a set value without increasing the flow rate of carrier gas. It is something to do.

[Summary of the invention]

The gas supply device for vapor phase growth of the present invention supplies a carrier gas to a bubbler tank through a controller to evaporate a raw material liquid, and supplies a mixed gas of the raw material gas and carrier gas into a reactor through the controller. The growth gas supply device is characterized in that a heater is provided in the supply path of the carrier gas to the bubbler tank.

According to such a gas supply device for vapor phase growth, the temperature drop in the raw material liquid caused by the loss of vaporization heat in the bubbler tank can be compensated for by the amount of heat possessed by the heated carrier gas. The flow rate of the raw material gas can be controlled to the set value without increasing the flow rate much. Furthermore, since the carrier gas flow rate can be stabilized, fluctuations in reaction conditions can also be prevented.

[Embodiments of the invention]

Embodiments of the present invention will be described below with reference to FIG. Note that in FIG. 1, the same members as in FIG. 2 are given the same numbers and their explanations are omitted.

In FIG. 1, the configuration of the controller 1 and the connection between the controller 1 and the bubbler tank IO are the same as those of the conventional device shown in FIG. A heater 12 is provided in the middle of the carrier gas supply pipe from the outlet of the controller l to the bubbler tank lO, so that the carrier gas can be heated. Further, the flow rate control of the raw material gas is performed in exactly the same manner as in the conventional apparatus.

Actually, using the apparatus of the above embodiment and the conventional apparatus shown in FIG.
The table below shows the results of examining changes in the temperature of the 5iCJILa liquid in the bubbler tank and the carrier gas flow rate when attempting to control the flow rate of the 5iC14 gas to a substantially constant level using u4.

In addition, the temperature of the carrier gas is 20°C in the conventional device δ.
, in the apparatus of the above example, it was 60°C.

Also, the Jllll constant is 100% when the carrier gas starts flowing.
This was done after a few minutes had passed.

As is clear from the table above, in the conventional device, the temperature of the bubbler tank drops significantly after 100 minutes, and the flow rate of the carrier gas increases significantly in order to control the IT of 5iCi4 gas. On the other hand, in the device of the above embodiment, 10
Even after 0 minutes, the temperature of the bubbler tank does not decrease much, and even if the carrier gas flow rate does not increase much, S i Cl
It can be seen that the 1 & charge of a gas can be controlled almost according to the set value.

In the present invention, it is possible to directly heat the bubbler tank or the raw material liquid itself, but since the cooling of the raw material liquid due to the removal of vaporization heat occurs only on its evaporation surface, It is more efficient to heat the carrier gas.

〔Effect of the invention〕

As detailed above, according to the gas supply device for vapor phase growth of the present invention, the flow rate of the raw material gas can be controlled almost to the set value without increasing the flow rate of the carrier gas, and the flow rate of the carrier gas can be stabilized. This has significant effects such as cost reduction in the vapor phase growth process and prevention of fluctuations in reaction conditions.

[Brief explanation of drawings]

FIG. 1 is a block diagram of a gas supply apparatus for vapor phase growth in an embodiment of the present invention, and FIG. 2 is a block diagram of a conventional gas supply apparatus for vapor phase growth. 1... Controller, 2... Mass flow sensor, 3
...Thermal valve, 4...Ratio detector, 5
... Arithmetic circuit, 6... Control circuit, 10... Bubbler tank, 11... Raw material liquid, 12... Heater.

Claims (1)

[Claims] A gas supply device for vapor phase growth in which a carrier gas is supplied to a bubbler tank through a controller to evaporate a raw material liquid, and a mixed gas of the raw material gas and carrier gas is supplied into a reactor through the controller, wherein the carrier gas bubbler A gas supply device for vapor phase growth, characterized in that a heater is provided in a supply route to a tank.