JPS6341880B2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to an optical CVD apparatus.

Conventionally, as a method for forming thin films, CVD involves subjecting a reactive gas to a thermal decomposition reaction or plasma decomposition reaction, and growing crystals of the reactant on a substrate to form a thin film.
(Chemical Vapor Deposition) method is known. In these methods, the substrate surface is heated to approximately 500℃.
If the reactant is not heated to 700°C, the crystals of the reactant will not grow and a good quality thin film will not be formed. However, at such a temperature, the constituent atoms of the reactant will be removed from the substrate, that is, an induced defect phenomenon in the substrate crystal will occur, leading to defects. Hyper
There is a disadvantage that LSI and compound semiconductors are manufactured and prevail.

In order to eliminate this inconvenience, light such as ultraviolet rays or laser beams is transmitted from light source a to substrate b as shown in the first diagram.
For this purpose, an optical CVD method has been proposed in which crystal growth is performed by exciting reactive gas molecules near substrate b and also exciting the surface of substrate b. According to this method, the temperature of the substrate surface is controlled to reduce the induced defects in the substrate crystal. It is advantageous that crystals of the reactant can be grown on the substrate even at a temperature so low that it does not occur.

However, this optical CVD method has the inconvenience of requiring a power source for a light source such as a laser beam.

The purpose of the present invention is to provide an optical CVD apparatus free from such inconveniences, and a substrate and a heater heated by a high-frequency coil outside the compartment are provided in a compartment through which a reaction gas flows, and the reaction gas is heated by a high-frequency coil. Irradiates light from a light source to cause a chemical reaction in the gas,
In the type of forming a thin film of a reactant on the substrate, the light source is constituted by a discharge chamber through which He or other discharge gas that emits light at a high frequency of the high frequency coil provided on the outer periphery of the compartment chamber flows. It consists of

Embodiments of the present invention will be described with reference to the drawings. In Fig. 2, 1 is an oblong transparent glass compartment with reaction gas inlets 2 and exhaust ports 3 on the left and right sides, and 4 is a platform-shaped compartment made of a conductive material provided inside the compartment 1. A heater 5 indicates a silicon or other substrate placed on the heater 4, and a mixed gas having a composition of, for example, arsine, trimethylgallium, trimethylaluminum, etc. is injected into the compartment 1 from the inlet 2.
It is injected to a pressure of 10 Torr to 760 Torr. Reference numeral 6 denotes a discharge chamber constituting a light source 7 formed around the outer periphery of the compartment 1;
Discharge gas such as H ₂ , He, Ne or Ar is 0.01~
It is circulated and supplied from the inlet 8 to the outlet 9 at a pressure of 1 Torr. The gas in the discharge chamber 6 glow discharges by energizing the high frequency coil 10 on its outer periphery, and the discharge light excites the reaction gas and the substrate 5 in the compartment 1. The high frequency coil 10 is supplied with electric power whose current, frequency, etc. are controlled so that the heater 4 is heated to a temperature of, for example, 560° C., which does not cause crystal defects in the substrate 5. The excited reaction gas reacts with the substrate 5 and grows on the surface of the substrate 5, forming, for example, an epitaxial film.

The compartment 1 can be formed vertically in a bell shape as shown in the third figure, and the heater 4 on which the substrate 5 is placed can be rotated by a drive shaft 11 introduced into the compartment 1. Good too. Furthermore, high frequency coil 1
0 is divided into a coil 10a for glow discharge and a coil 10b for heating the heater 4, as shown in FIGS. 4 and 5, and the temperature of the heater 4 can be controlled by controlling the high frequency power of the coil 10b. I can do it. To explain its operation, when a discharge gas such as Ar is passed through the discharge chamber 6 and electric power is supplied to the high frequency coil 10 so that the temperature of the heater 4 becomes a temperature that does not cause defects in the crystal of the substrate 5, The crystal of the substrate 5 is heated to a temperature that does not induce defects, and the discharge gas in the discharge chamber 6 glow discharges under the action of the magnetic field of the coil 10. Next, when a reactive gas is injected into the compartment 1, the gas is excited by the light generated by the glow discharge in the discharge chamber 6, and at the same time a reaction occurs on the excited surface of the substrate 5, forming, for example, an epitaxial film there. .

In this way, according to the present invention, the light source for irradiating the reaction gas is configured with a discharge chamber provided on the outer periphery of a compartment chamber through which discharge gas flows, and the discharge gas is caused to discharge and emit light using high frequency waves for heating the heater. So,
Since the light source can be formed integrally with the compartment, there is no need to install a separate light source, and there is no need to specifically provide a power source for the light source, so the configuration of the optical CVD device can be simplified and assembly can be facilitated.

[Brief explanation of the drawing]

Figure 1 is a cross-sectional diagram of a conventional optical CVD device, Figure 2
The figure shows a sectional view of an embodiment of the apparatus of the present invention, and FIGS. 3 to 5 show sectional views of other embodiments of the invention. DESCRIPTION OF SYMBOLS 1... Compartment chamber, 4... Heater, 5... Substrate, 6... Discharge chamber, 7... Light source, 10... High frequency coil.

Claims (1)

[Claims] 1. A substrate and a heater heated by a high-frequency coil outside the compartment are provided in a compartment through which a reaction gas flows, and light is irradiated from a light source to cause a chemical reaction in the reaction gas to cause a reaction on the substrate. In a type that forms a thin film of an object, the light source emits light at a high frequency from the high frequency coil provided on the outer periphery of the compartment.
An optical CVD device consisting of a discharge chamber through which He or other discharge gas flows.