JPH0557355B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a vertical gas phase reactor using high frequency induction heating.

[Conventional technology]

High-frequency induction heating using a high-frequency coil is widely used in gas-phase reactors. for example,
Such high frequency induction heating is widely used in epitaxy equipment.

However, when a vertical type is used to perform a gas phase reaction using high-frequency induction heating, if a reduced pressure type is used, the problem of abnormal discharge occurs.

For example, a pancake-type vertical reactor, which is a type of vertical gas-phase reactor, is a reactor in which a high-frequency coil 2' is defined by a bell gear 11' (usually made of quartz), as shown in FIG. Since it is located inside 1',
When the pressure inside the furnace is reduced, the high-frequency coil 2' is also placed under reduced pressure, resulting in abnormal discharge. When abnormal discharge occurs, the load impedance changes significantly, the discharge becomes unstable, and the oscillator may be damaged. (In Figure 1, 3' is a carbon support, 4' is a wafer, 5' is a quartz cover,
Arrows are gas flows. ) In practice, when the pressure inside the furnace is set to about 100 to 200 Torr, it is difficult to heat the furnace to over 1100°C without electrical discharge, and the problem of electrical discharge is unavoidable. In a high pressure range of 200 Torr or more, where the pressure is not reduced that much, there is not much of a problem with discharge, but in order to make it a pressure reduction type, it is still necessary to solve the problem of discharge.

As a result, in conventional gas-phase reactors using high-frequency induction heating, when the degree of vacuum increases (for example, P
In practice, vapor phase growth at P100 Torr is difficult and virtually impossible, since discharge is more likely to occur at P100 Torr.

[Purpose of the invention]

An object of the present invention is to provide a vertical gas phase reactor capable of high-frequency induction heating under reduced pressure.

[Structure of the invention]

The vertical gas-phase reaction device using high-frequency induction heating of the present invention has a configuration in which the part where the gas-phase reaction is performed and the part where the high-frequency coil is located are separated, allowing the two parts to have different pressures. shall be.

[Action of the invention]

As a result of the above configuration, the reactor where the gas phase reaction takes place is separated from the high-frequency coil section that causes abnormal discharge, so even if the pressure inside the furnace is reduced, the high-frequency coil section will be at an arbitrary pressure, that is, higher than the furnace internal pressure. Since the pressure can be maintained at normal pressure or low pressure, it is possible to prevent abnormal discharge that would otherwise occur due to reduced pressure in the area where the high-frequency coil is located. Therefore, a gas phase reaction by high frequency induction heating under reduced pressure becomes possible.

In addition, by separating the two parts, the capacity of the furnace itself can be reduced, and therefore the bell gear, which is generally made of quartz, can be made smaller. Moreover, the furnace purge time can be shortened. Further, it is possible to suppress metal contaminants from entering the furnace from the high-frequency coil, and it is possible to prevent wafers and the like from being contaminated by metal. In addition, the purge gas for the high-frequency coil section can be replaced by inexpensive nitrogen.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows an example in which the present invention is applied to a so-called pancake-type vertical furnace.

In this example, by installing the high-frequency coil 2 outside the reactor 1, the reactor 1 where the gas phase reaction is performed is separated from the part where the high-frequency coil 2 is located.

Graphite on which wafers etc. to be heated are placed
The susceptor 3 is installed in the furnace so as to be close to the high frequency coil 2, which is a work coil.

In this example, stainless steel bell gear 11a (water-cooled type)
and a quartz inner bell gear 11 constitute a reactor 1, and a reactant gas (hydrogen or silane gas) is sent into the reactor from a quartz nozzle 4.

As mentioned above, the high-frequency coil 2 is installed outside the reactor 1 to separate the two, so the gas phase reaction can be performed under reduced pressure, and even in that case, the high-frequency coil 2 is affected by the effect of the reduced pressure Therefore, problems such as discharge do not occur. Therefore, even if the reaction is carried out under reduced pressure conditions of 100 Torr or less,
The high frequency coil 2 can be placed under normal pressure (or low pressure), allowing gas phase reactions to occur under reduced pressure.

With the configuration of this example, it is possible to suppress metal contaminants from entering the furnace from the high frequency coil 2, and to prevent wafers and the like from being contaminated by metal. Cheap nitrogen can also be used as the purge gas for the high frequency coil section. Furthermore, since the length of the high-frequency coil 2 in the vertical direction (vertical direction in FIG. 1) may be reduced by extending the high-frequency coil 2 to the outside, it is also possible to reduce the capacity of the furnace itself. Therefore, it is advantageous that the bell gear (especially the quartz bell gear 11) can be made small. Moreover, the furnace purge time can be shortened.

Shown in FIG. 2 is another embodiment of the invention. In this example, a storage section 21 for the high-frequency coil 2 is formed in a space defined by the bell gears 11 and 11a, and this storage section 21 is airtightly isolated from the reaction section 1a where the gas phase reaction is performed. , which made it possible for the pressures on both sides to be different.

This example also exhibits the same effects as the previous example. In addition, in this example, the pressure in the high frequency coil 2 can be controlled more reliably. In FIG. 2, the same reference numerals are given to the same components as in the above example.

It should be noted that, as a matter of course, the present invention is not limited to the illustrated example.

〔Effect of the invention〕

As mentioned above, the vertical gas phase reactor of the present invention includes:
By solving the problem of high-frequency coil discharge, it became possible to perform gas-phase reactions using high-frequency induction heating under reduced pressure.

[Brief explanation of the drawing]

FIG. 1 and FIG. 2 are sectional views each showing an embodiment of the present invention. FIG. 3 shows a conventional example. 1, 1a... Reaction furnace (gas phase reaction section), 2... High frequency coil, 21... High frequency coil storage section.

Claims (1)

[Claims] 1. In a vertical gas phase reaction device using high frequency induction heating, by separating the part where the gas phase reaction takes place and the part where the high frequency coil is located, it is possible to have different pressures in both parts. A well-developed high-frequency induction heating gas phase reactor. 2. The high-frequency induction heating gas-phase reactor according to claim 1, wherein the pressure inside the reactor in which the gas-phase reaction is carried out is reduced, and the high-frequency coil is placed under normal pressure or under a pressure higher than the pressure inside the furnace.