JPS6366924A - Manufacture of solid-state thin-film through photo-cvd - Google Patents

Abstract

PURPOSE:To prevent the reduction of the quantity of optical transmission due to the adhesion of a reaction product onto an optical transmitting window member easily and positively by introducing a first gas having atoms contained in a solid-state thin-film to be formed near a substrate at a position where separate from a transmitting window for beams for excitation and guiding a second gas except the first gas near the transmitting window. CONSTITUTION:A first gas having atoms contained in a solid-state thin-film to be shaped is introduced at a position in a reaction vessel 1 separate from a transmitting window 2 for the reaction vessel 1, through which beams for excitation from a light source 3 pass, and near a substrate 4 to be grown in the vapor phase, and a second gas except the first gas is guided neat the transmitting window 2. A gas acquired by exciting the second gas at two steps or more by a plurality of light sources 3 and brought under the state of excitation of high energy is generated in a photo-CVD reaction, and the decomposition and reaction efficiency of the first gas for the photo-CVD reaction are accelerated remarkably by the direct chemical reaction of the gas under the state of excitation of high energy and the first gas. Said reaction vessel 1 is partitioned into a chamber such as a first chamber 12 on the substrate 4 and a chamber such as a second chamber 11 on the optical transmitting window member 2 by a partition wall 13, and the first chamber 12 is supplied with the mixed gas of SiH4 and N2 and the second chamber 11 with O2.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention utilizes so-called optical CVD (Chemical CVD) for manufacturing solid thin films of semiconductors such as silicon.
A solid thin film by apor D deposition)! l! Regarding the method of sending.

In the prior art, a mixed gas of SiH<02 and N20 is supplied into a reaction vessel in order to vapor phase grow silicon on a substrate. The light passage window provided in the reaction vessel has
Light from a light source, such as a mercury lamp, located outside the reaction vessel is directed, and this light is directed onto the substrate.

In such prior art, 5i02 adheres to the light passing window during the vapor phase growth reaction, and the amount of light from the light source passing through the light passing window is reduced. Therefore, it has become difficult to efficiently grow SiO2 on a substrate in a vapor phase.

A prior art technique for solving this problem is disclosed in, for example, Japanese Patent Laid-Open No. 57-187033. In this prior art, a Si wafer is placed facing a space formed by a quartz window as a light passing window member, Xe gas is flowed on the quartz window side, and S for photo-CVD reaction is placed on the Si wafer side.
i H4 and N H gases are flowed as a laminar flow. Light is irradiated from an external light source through the quartz window.1 The quartz window is placed below the Si wafer! This causes gas with a high specific gravity to flow along the quartz window, thus preventing reaction products from adhering to the quartz window.

In such prior art, the XeW gas and the photoCVD reaction gas must flow in a laminar flow, and in order to maintain such a state, the flow rates and pressures of these gases must be adjusted slightly. This requires adjustment, and there is a problem in that reaction products tend to adhere to the quartz window.

Furthermore, when the quartz window is placed below as described above, Xe1f, which is a gas with a higher specific gravity than the reaction gas,
Conversely, when a quartz window is placed above and light is irradiated from above externally, a gas of low specific gravity, for example He1f, is placed above the reactant gas along the quartz window. The problem is that the types of gases that must be flushed are thus limited.

An object of the present invention is to easily and reliably prevent reaction products from adhering to a light-transmitting window member through which light for photo-CVD reaction passes and reducing the amount of light passing through. An object of the present invention is to provide a method for manufacturing a solid thin film by photo-CVD.

In the present invention, atoms contained in a solid thin film to be formed are located in a reaction vessel at a position remote from a passage window of the reaction vessel through which excitation light from a light source passes, and in the vicinity of a substrate to be vapor-phase grown. gi gas, and a second gas other than the first gas to the vicinity of the passage window. In the photo-CVD reaction, the second ff gas is excited in two or more stages by multiple light sources to create a high-energy excited state gas, and this A method for producing a solid thin film by photo-CVD, characterized in that the decomposition of the first gas for the photo-CVD reaction and the reaction efficiency are greatly accelerated by a direct chemical reaction between the gas in a high-energy excited state and the first, f-s. It is.

FIG. 1 is a sectional view showing the basic configuration of the present invention,
FIG. 2 is a simplified plan view thereof.

An opening is formed in the reaction vessel 1, and a translucent passage window member 2 made of CaF2 or the like is provided in this opening for passing excitation light. The short wavelength light from the deuterium lamp 3 can reach the substrate 4 which is a silicon wafer.
Inside: A 11f gas for reaction is supplied from a conduit 5 through a nozzle 6 to a position within the reaction vessel 1 remote from the light passage window member 2 and near the substrate 4 to be subjected to vapor phase growth.

This reaction gas may consist of SiH, 10mol% and N2 of 90IIlo1% to dilute it. 02 as the 27th y gas is led from the conduit 7 to the vicinity of the light passing window member 2, and the nozzle 8 toward the light passing window member 2. The substrate 4 is heated by a heater 9. The reaction vessel 1 may be made of quartz glass, stainless steel, etc., for example. Reactant gas from line 5 and zero from line 7
2 may be, for example, about 0.6:1 to 1:1.

The nozzle 8 is formed in an opening 8a, and 02 is supplied from the conduit 7 to this opening 8a. A flow regulator 7a is provided in the portion of the pipe 7 that is supplied to the frontage 8a, so that the nozzles 8 directed radially inward spray 0□ at approximately the same flow rate. Another nozzle 6
Similarly, the opening 6a is connected to the opening 6a, and the reaction gas is supplied to the opening 6a from the conduit 5 as described above.

The deuterium lamp 3 generates ultraviolet light having a short wavelength band shorter than 200 mm. As shown in FIG. 3, o2 has a large absorption spectrum in such a short wavelength band, for example around 135-1701. Therefore, 02 can be efficiently excited using the deuterium lamp 3, and therefore, 5 in 2 vapor phase growth can be performed on the substrate 4 at a relatively low temperature.

FIG. 4 is a cross-sectional view of one embodiment of the present invention, which is similar in construction to that previously described, and corresponding parts have been given the same reference numerals. What should be noted is that the first chamber 12 of the substrate 411III and the second chamber 11 on the light passing window member 2 side are separated by J! ! 13
Separate by. This distance! S! A passage hole 14 is formed in 13 for guiding the excited reaction gas and for guiding excitation light from the light passage window member 2 to the substrate 4 . The tlIJ1 chamber 12 contains SiH, which is a reactive gas,
A mixed gas of N2 and N2 is supplied from the nozzle 6. Another reaction gas, 02, is supplied to the second chamber 11 from the nozzle 8 at a higher pressure than the reaction gas led to the fjS1 chamber 12. According to such a configuration, ozone excited in the second chamber 11 flows from the passage hole 14 to the first chamber 12, and the photoCVD reaction is promoted. At this time, nozzle 6
The reaction gas from the reactor gas hardly flows into the second chamber 11.

Therefore, there is little possibility that S;02 or the like will adhere to the light passing window member 2 and the amount of light from the deuterium lamp 3 will decrease.

FIG. 5 is a system diagram of another embodiment of the present invention.

Corresponding parts of the previous embodiments are given the same reference numerals. O3 is supplied from the pipe line 16. This oxygen 02 is supplied to a deuterium lamp 1 which generates short wavelength light in an excitation chamber 17.
8 becomes excited oxygen 03. This excited oxygen O1 is supplied into the reaction chamber from a nozzle 8 in the reaction container 1 via a pipe 19 and a pipe 7. A reaction gas is supplied from the pipe line 5 to the nozzle 6 . The light passing window member 2 includes a light source that generates short wavelength light, such as a mercury lamp, a xenon lamp,
A light source 20 such as an excimer laser or a mercury xenon lamp is provided.

In the excitation chamber 17, excited oxygen O1 is produced by a deuterium lamp 18 that generates short wavelength light with a good oxygen absorption spectrum. This excited oxygen 0. has a long life and has an absorption spectrum of light emission at a wavelength as shown in the Pt5a diagram. Therefore, within the reaction vessel 1, this excited oxygen 0. is excited by the light source 20 of the wave light. In this way, by efficiently exciting Ol and using photo-CVD,
A semiconductor thin film can be deposited on the substrate 4 .

FIG. 7 is an energy transfer diagram illustrating the principle of the present invention.

Referring to this figure, if the photoexcitation energy of the first gas for reaction in a CVD reaction is El, it has an energy E1 of recombination radiation from an excited state, and the energy E
An f52 gas having a large absorption coefficient with respect to another energy E2 required for excitation to 1 is prepared, and in addition to the first gas of optical CVD and the light source 11 having excitation energy E1, the light LWI2 having excitation energy E2 and By intervening the second gas at the same time, the decomposition efficiency of the first gas in photo-CVD can be significantly accelerated.

FIG. 8 is another energy transfer diagram for explaining the present invention in detail. Referring to this figure, in the photoCVD reaction, the second gas is excited in two or more stages by multiple light sources such as I3 and 14, and contains a gas in a high-energy excitation state such as Ol. Decomposed into gas and highly chemically active O radicals. The direct chemical reaction between O and the first gas can significantly speed up the decomposition of the first gas and the reaction efficiency for the photo-CVD reaction.

As described above, according to the present invention, a solid thin film such as a semiconductor can be efficiently and stably grown in vapor phase over a long period of time without clouding the light passage hole and therefore without attenuating the amount of light from the light source. It becomes like this.

In particular, in the present invention, the light passing window member 2 side and the heater 9 (111 that heats the substrate 4) are partitioned by a partition wall 13, and the second chamber 11 on the light passing window member 2 side has a heater 9 (111) that heats the substrate 4. A second gas that does not deposit on the light passing 'BBH 3 is injected from the second nozzle 8, and this second gas enters the first chamber 12 on the substrate 4 side.
The pressure is higher than that.

Therefore, the first gas in the first chamber 12 is separated from the second chamber 11! !
! Flowing through the passage holes 14 of 13 is reliably prevented.

Furthermore, a vacuum pump is connected to the fjSl chamber 12 on the opposite side of the substrate 4 from the first nozzle 6 (that is, below the substrate 4 in FIG. 4) to suck gas.

These I holes prevent the first gas from flowing into the second chamber 11 side, and certainly prevent material from accumulating on the light passage window member 2.

The first and second nozzles 6.8 are configured to inject the first and second gases radially inwardly at the outer periphery of the light path, thus allowing the light source 3 to pass through the light passage window member 2. The light from ,20 is not blocked,
PhotoCVD reaction can be performed reliably.

Furthermore, in the present invention, the second gas may be any type of gas that is injected toward the light passing window member 2 and does not accumulate thereon, and the excellent advantage is that the type of gas can be selected as desired. There is.

That is, this second gas may be the 02 gas that reacts with tjSl and fs as in the above embodiment, and does not react with other gases such as the first gas and does not deposit on the light passing window member 2. Other types of gas may also be used.

[Brief explanation of drawings]

tjSl diagram is a sectional view showing the basic configuration of the present invention, FIG. 2 is a simplified plan view of the embodiment shown in tjSl diagram, FIG. 3 is a graph showing absorption spectrum 1 of 02, FIG. 4 is a cross-sectional view of one embodiment of the present invention, FIG. 5 is a cross-sectional view of yet another embodiment of the present invention, FIG. 6 is a graph showing the absorption spectrum of ozone, and FIG. FIG. 8 is an energy transfer diagram illustrating the activation of another principle of the invention. DESCRIPTION OF SYMBOLS 1... Reaction perforator, 2... Light passage window member, 3,18.
...Deuterium lamp, 4...Substrate, 5, 7, 16.19
...Pipeline, 6,8...Nozzle, 9...Heater, 11...Second chamber, 12...First chamber, 13...Partition wall, 14...Light passage hole, 17...excitation chamber, 20...
・Long-wavelength light source agent Patent attorney Shisan Keiichi Part 3 Figure 3 V & 4 Figure 6 Figure 6 Cover] (1) Figure 7 Figure 2 Power 8 Figure 7 2-curse procedural amendment (method) 1988 9 January 28, 1, Indication of the case Patent application No. 62-69695 2. Name of the invention Method for manufacturing solid thin films by optical CVD 3. Person making the amendment Relationship to the case Applicant Address 3-chome, Ichihanayashiki, Kawanishi City, Hyogo Prefecture 17-4 Name: Hamakawa Ibutsu 4, Agent address: Shinkosan Building Kokusai EX, 1-13-38 Nishihonmachi, Nishi-ku, Osaka 0525-5985 INTAPT
J International FAX GIff&GII (06)538-0
2476, Specification to be amended 7, Specification of contents of amendment cleared (no change in content). that's all

Claims (1)

[Claims] At a position in the reaction vessel away from the passage window of the reaction vessel through which the excitation light from the light source passes, and in the vicinity of the substrate to be subjected to vapor phase growth, a first
A second gas other than the first gas is guided near the passage window, and the second gas is excited in two or more stages by a plurality of light sources in a photo-CVD reaction to create a high-energy excited state gas, Production of a solid thin film by photo-CVD, which is characterized in that the direct chemical reaction between this high-energy excited state gas and the first gas greatly accelerates the decomposition of the first gas for the photo-CVD reaction and the reaction efficiency. Method.