JPH02302394A - Film-forming apparatus - Google Patents

Abstract

PURPOSE:To obtain a film-forming apparatus capable of lowering the film- forming temperature and producing a high quality thin film by decomposing. ionizing or exciting a gas introduced into a vacuum chamber with an ultraviolet- radiation lamp and making the gas to collide with a heated substrate. CONSTITUTION:The side wall of a vacuum chamber 1 of the subject film- forming apparatus is provided with a cell 13 produced by providing a low- pressure mercury lamp 10 for radiating ultraviolet ray and a gas-inlet nozzle 11 to introduce O2 gas as a reaction gas and fixing the lamp and the nozzle to one flange 12. Accordingly, a molecular beam is generated by evaporating an evaporation source from a pair of Knudsen cells 2a, 2b. O2 gas as a source of the molecular beam is decomposed, ionized or excited by ultraviolet ray radiated from the low-pressure mercury lamp 10 and is made to collide with a substrate 3 heated with a heater 4. A thin layer grown by epitaxial growth at a low temperature can be formed on the surface of the substrate 8 by this process.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a film forming apparatus for forming an epitaxially grown thin film layer on the surface of a substrate.

(Prior Art) In a conventional film forming apparatus in which a gas source substance is used as a crystal constituent element, as shown in FIG. Knudsen cells 2a and 2b are arranged, and there is also a vacuum chamber! A substrate 3 is placed in the upper part of the cell so as to face the Knudsen cells 2a and 2b.

A substrate heater 4 is provided on the back of the substrate 3. An oxygen gas introduction nozzle 5 is attached to a flange boat 1a on the side wall of the vacuum chamber 1, and oxygen gas ejected from the oxygen gas introduction nozzle 5 flows toward the substrate 3.

In the figure, 6 and 7 are liquid nitrogen shrouds, 8 is a preparation chamber, and 9 is a gate valve.

Therefore, in the above device, the oxygen gas introduction nozzle 5
While introducing more oxygen gas, two Knudsen cells 2
When the evaporated substances are evaporated from a and 2b to generate molecular beams, and the substrate 3 is heated by the substrate heater 4, a thin film layer is epitaxially grown on the surface of the substrate 3.

(Problem to be solved by the invention) Since the conventional film forming apparatus has the above-mentioned configuration,
When forming an epitaxially grown thin film layer on the surface of the substrate 3, it is necessary to perform treatments such as introducing a large amount of oxygen gas at a high substrate temperature or annealing at high temperature in an oxygen atmosphere after film formation. Problems occurred in that the film-forming atmosphere in the vacuum chamber 1 deteriorated due to the introduction of oxygen gas, and the quality of the thin film formed on the surface of the substrate 3 deteriorated due to annealing at a high temperature. In addition, a large amount of oxygen gas introduced near the surface of the substrate 3 may disturb the molecular beams from the two Knudsen cells 2a12b, or an increase in the oxygen partial pressure in the vacuum chamber 1 may cause the Knudsen cells 2a, There also occurred a problem that heating filaments such as 2b deteriorated early.

This invention solves the above-mentioned conventional problems and improves the film forming atmosphere in the vacuum chamber by introducing as little oxygen gas as possible, which is necessary for epitaxial growth, and eliminates the disturbance of molecular beams caused by oxygen gas. It is an object of the present invention to provide a film forming apparatus that can reduce early deterioration of the substrate and lower the substrate temperature using activated gas ionized or excited by ultraviolet rays.

(Means for Solving the Problems) In order to achieve the above object, the present invention places a molecular beam generation source and a substrate facing each other in a vacuum chamber into which gas is introduced from a gas introduction nozzle, and heats the substrate at the back of the substrate. In a film forming apparatus equipped with a heater, a lamp that emits ultraviolet rays is installed in the vacuum chamber, and the ultraviolet rays from this lamp decompose, ionize, or excite the gas and activate it, thereby creating a low temperature on the surface of the substrate. It is characterized by forming a thin film layer epitaxially grown.

(Function) In this invention, molecular beams are generated from a molecular beam generation source, and the gas introduced from the gas introduction nozzle is decomposed, ionized, or excited by a lamp that emits ultraviolet rays, and then,
When it is applied to a substrate heated by a substrate heater, a thin film layer is epitaxially grown on the surface of the substrate at a lower substrate temperature.

(Example) Hereinafter, an example of the present invention will be described with reference to the drawings.

FIG. 1 shows an embodiment of the present invention. In the same figure, the same reference numerals as in FIG. Instead of the gas introduction nozzle, a low-pressure mercury lamp 10 that emits ultraviolet rays and a gas introduction nozzle 11 that introduces oxygen gas as a reaction gas as shown in FIG. 2 are installed on one flange 1.
A cell 13 made by fixing the cell 2 to the vacuum chamber 1 is attached to a flange boat la on the side wall of the vacuum chamber l.

Therefore, in the above embodiment, two Knudsen cells 2
A and 2b evaporate the evaporated matter to generate a molecular beam, and the oxygen gas introduced from the gas introduction nozzle 11 is decomposed, ionized or excited by a low-pressure mercury lamp lO that emits ultraviolet rays, and then it is When applied to the substrate 3 heated by the substrate heater 4, a thin film layer epitaxially grown at a low temperature is formed on the surface of the substrate 3.

In the above embodiment, the cell 13 is attached to the flange port 1a on the side wall of the vacuum chamber 1, but the invention is not limited thereto.
Alternatively, the cell 13 may be attached to the flange boat 1c at the bottom of the vacuum chamber 1. Further, a conventional oxygen gas introduction nozzle 5 is attached to the flange boat 1a on the side wall of the vacuum chamber l, and a cell 13 in which the gas introduction nozzle 11 is closed is attached to the flange boat 1b on the side wall of the vacuum chamber l next to the substrate 3. Good too. Furthermore, although oxygen gas is used as the reaction gas introduced from the gas introduction nozzle 11, various gases necessary for film formation, such as Os and NtO, may be used instead. Furthermore, depending on the type of reaction gas introduced from the gas introduction nozzle 11, instead of the low pressure mercury lamp,
A lamp with a wavelength necessary for activation of Kr, Xe, etc. may be used. Further, instead of the two Knudsen cells 2a and 2b, the number of Knudsen cells may be increased. Further, instead of the Knudsen cell, a gas cell, a clutching cell, a sputter target, a reaction gas from a CVD device, etc. may be used as long as the source is for forming a thin film layer on a substrate.

(Effects of the Invention) According to the present invention, the following effects can be achieved.

(1) The gas introduced from the gas introduction nozzle is decomposed, ionized, or excited by a lamp that emits ultraviolet rays, and then applied to the substrate heated by the substrate heater, so the film can be formed. The temperature can be lowered, and high-quality thin films can be obtained without the need for, for example, annealing the substrate after film formation.As a result, deterioration of the thin film surface is prevented, and heterojunctions with different types of thin films are prevented. Made possible in good condition.

(2) Since the amount of gas introduced can be reduced, the pressure near the substrate can be lowered, making it possible to prevent disturbance of the molecular beam.

(3) Since the partial pressure of the gas in the vacuum chamber could be lowered, it was possible to reduce early deterioration of the heating filament, etc.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing an embodiment of the invention, and FIG. 2 is an explanatory diagram used in the embodiment of the invention. FIG. 3 is an explanatory diagram showing a conventional device. In the figure, 1... Vacuum chambers 2a, 2b... Knudsen cell 3... Substrate 10... Low pressure mercury lamp 11... Gas introduction nozzle 13... Cell Nao. In the drawings, the same reference numerals indicate the same or corresponding parts. Patent applicant: Japan Vacuum Technology Co., Ltd. No. 1vA Figure 2 Figure 3

Claims (1)

[Claims] 1. In a film forming apparatus in which a molecular beam generation source and a substrate are placed facing each other in a vacuum chamber into which gas is introduced from a gas introduction nozzle, and a substrate heater is provided on the back of the substrate, a lamp that emits ultraviolet rays is connected to the vacuum chamber. A film forming apparatus that is attached to a chamber and activated by decomposing, ionizing, or exciting the gas using ultraviolet rays from the lamp, thereby forming a thin film layer that is epitaxially grown on the surface of the substrate at a low temperature.