JPS631026A - Manufacture of semiconductor - Google Patents

Abstract

PURPOSE:To improve the quality of a film remarkably by using optical energy to replenish reaction energy on a substrate surface. CONSTITUTION:SiH2, Si2H6 or a gas containing one of these materials is introduced into a reaction chamber 1 of high vacuum, a high-frequency power 3 is applied to upper and lower electrodes 2u and 2d to decompose the material gas, and a film is formed on a substrate S by a vapor-phase chemical reaction of a product of decomposition. On the occasion, light of wavelength 230-450 nm is generated from a light source 4. For this source, a low-pressure Hg lamp (254 nm), excima laser such as KrF (249 nm), XeCl laser (308 nm) or XeF (251 nm) or N2 gas laser (337 nm) is employed. According to this construction, a reaction energy on the surface of the substrate is increased to facilitate reaction even when the reduction of an impressed voltage and the separation of a discharge chamber from a deposition chamber are made to protect the film from high-energy particles, and therefore the quality of the film can be improved remarkably.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a method for manufacturing semiconductors such as amorphous semiconductors or microcrystalline semiconductors.

[Prior art]

As a method for creating semiconductors using parallel plate type glow discharge electrodes, the method shown in Figure 5 is conventionally known (J
apanese Journal of Applia
d Physics Supplement 20-2
(1980) p. 163).

FIG. 5 is a schematic diagram showing a semiconductor manufacturing method using a conventional parallel plate type glow discharge box, and 1 in the figure indicates a high vacuum reaction chamber. In the reaction chamber 1, a pair of electrodes 2u and 2d are disposed in parallel on the upper and lower sides, a substrate S is disposed on the lower electrode 2d, and upper and lower types tf+ 2.4 are formed.

A high-frequency voltage is applied by the high-frequency power source 3 during the 2d period to generate plasma discharge, decompose the raw material gas introduced into the reaction chamber 1, and based on the gas-phase 1hichemical reaction of the decomposition product, the group Is
Film formation is applied to the back surface.

By the way, in the method described above, high-energy particles in the plasma impinge on the film and cause damage to it, so in order to improve the film quality, it is necessary to reduce the applied power or increase the reaction chamber pressure. There were limitations to the film formation conditions, such as the lack of oxidation, and there was a lack of reaction energy on the substrate surface, limiting the ability to improve film properties.

As a means to solve this problem, the reaction chamber 1 is separated into two regions,
A method has been proposed, as shown in FIG. 6, in which the discharge producing high-energy particles is carried out within the discharge region, and the substrate is disposed within the deposition region.

FIG. 6 is a schematic diagram of a conventional device, which includes a discharge chamber 21 and a deposition chamber 22 that are connected to each other by a communication path 21a, and discharge is performed in the discharge chamber 21 separated from the deposition chamber 22. In addition, the structure is such that the substrate S in the deposition chamber 22 is not affected by high-energy particles (Proceedings of the 31st Applied Physics Conference, 1984, 31a-R-7).

In this method, a discharge is caused in a non-deposition gas such as Ar, 82, etc. in the reaction chamber 21 to generate active species such as Ar', H'', etc., and these active species cause a discharge in the deposition &ff chamber 22. The supplied raw material gas such as 5il14 + Si2116 is decomposed and a film is formed on the substrate S based on a gas phase chemical reaction.

[Problem that the invention seeks to solve]

However, if the discharge chamber 21 and the deposition chamber 22 are separated as described above, the influence of high-energy particles is extremely small, but the reaction energy on the substrate surface, which is required to improve film quality, tends to be low. This was a major obstacle in efforts to improve film quality.

The present invention has been made in view of the above circumstances, and its purpose is to provide a semiconductor molding method that uses light energy to replenish reaction energy on the substrate surface, thereby making it possible to significantly improve film quality. There is something to do.

[Means for solving problems]

In the method of the present invention, when monosilane, disilane, or a mixed gas containing at least one of these is used as the source gas, light with a wave fW of 230 to 450 nl is projected onto the substrate surface.

[Effect]

In the method of the present invention, the applied voltage is thereby reduced in order to reduce the influence of high-energy particles, and even when the discharge is performed in a discharge chamber separated from the deposition chamber in which the substrate is arranged, the substrate voltage tends to be lowered. It is possible to replenish the reaction energy on the surface, promote the reaction without being affected by high-energy particles, and improve the film quality.

〔Example〕

The present invention will be specifically described below based on drawings showing embodiments thereof. FIG. 1 is a schematic diagram showing the implementation state of the glow discharge method using parallel plate type electrodes to which the method of the present invention is applied, and in the figure, 1 is a reaction chamber, and 2u is a reaction chamber.

2d is an electrode, 3 is a high frequency power source, and 4 is a light source.

Upper and lower molds +i2u and 2d are placed above and below inside the reaction chamber 1, and a light source 4.4 is placed on the left and right sides (II+), and gas is supplied into the reaction chamber 1 set at high vacuum. A raw material gas is supplied from the device, and a required high frequency is applied to the upper and lower electrodes 2u and 2d by a high frequency power source 3 to decompose the raw material gas, and a film is formed on the surface of the group ffj S by a gas phase chemical reaction of the decomposition products. It is supposed to be done.

As the raw material gas, SiH4, Si2 Hs, or a mixed gas containing at least one of these is used.

In addition, as the light source 4.4, 5il14 is used as the raw material gas.
.

When using Si2)16 gas or a mixed gas containing at least one of these, a light source that emits light with a wavelength in the range of 230 to 450 nm, such as a low-pressure mercury lamp (wavelength:
254nm) + KrF laser (wave W: 24
9nm).

XeCj! Laser (wavelength: 308nm), XeF
An excimer laser such as a laser (wavelength: 251 nm) or an N2 gas laser (eL length: 337 r++n) is used.

In the case of ultraviolet light with a wavelength of less than 230 nm, the source gas molecules absorb the ultraviolet light, causing decomposition and excitation of the gas molecules, and the plasma state may be disturbed by the light. is light with a wavelength of 150 nm or more,
Further, Si2It6 gas hardly absorbs light having a wavelength of L210 nm or more, and this is because the Si2It6 gas can be effectively used as surface reaction energy.

In addition, the reason why the wave ffi is set to be 450 nm or less is that light in a region exceeding this causes vibrational excitation on the surface of the core or in the film.
The result is similar to that of an increase in substrate temperature, and energy is not only applied to the substrate surface, but also reaches into the already formed film, resulting in an increase in the amorphous silicon film (a-5i).
:H) Now for hydrogen! This is because problems such as 1iIt desorption or carrier generation and recombination occur, resulting in defects.

An example of specific reaction conditions is shown in Table 1.

(Margins below) In the experiment, amorphous silicon films were formed using the conventional parallel plate glow discharge method and the method of the present invention, which uses an ultraviolet light source. UV light with a wavelength of 253.7 nm (approximately 10 f
The results of examining the infrared absorption spectrum when irradiated with flW/cffi2) are shown in Figures 2 (a) and (b).

Figures 2 (a) and 2 (b) are graphs showing the results of comparative tests between the method of the present invention and the conventional method, in which the horizontal axis represents the wave number (1/wavelength) (ω-1), and the vertical axis represents absorption. It is expressed in terms of quantity (arbitrary unit). FIG. 2(a) shows the results of the method of the present invention, and FIG. 2(b) shows the results of the conventional method.

As is clear from this graph, absorption by the Si-It band at a wave number of around 2000 cm, which is observed when the film quality is good, is observed in the present invention, but absorption in the 5i-H2 band when obtained by the conventional method is observed. Only the absorption by the Si-II-band was observed, and no absorption by the Si-II-band was observed, indicating that the method of the present invention can improve the drawing quality.

FIG. 3.4 is a schematic diagram showing another state of implementation of the present invention, in which the vacuum chamber is separated into a discharge region and a thickening region 22. Ultraviolet light sources 24.24 are provided on the left and right side walls of the area 22, and in the embodiment shown in FIG. glass window 2
2a and 22a are arranged at the bottom of the groove.

In the method of the present invention, after setting the vacuum chamber to a predetermined degree of vacuum, raw material gas is injected, and the substrate S
A film is formed by heating the substrate to generate plasma in the discharge region and simultaneously irradiating it with light having a wavelength of 230 to 450 nm from an ultraviolet light source. Specific reaction conditions are as shown in Table 2.

It should be noted that although the above-mentioned embodiments were mainly explained in the case of forming an amorphous silicon film constituting a semiconductor,
It goes without saying that the present invention is not limited to this, and can be applied, for example, to the production of microcrystalline semiconductors.

(Margins below) Table 2 [Effects] As described above, in the method of the present invention, monosilane gas, disilane gas, or a small amount of a mixed gas containing one of these gases is used as the raw material gas for semiconductor film formation. Since the substrate surface is irradiated with light with a wavelength of 230 to 450 nm, it is necessary to reduce the applied voltage to protect the film from high-energy particles and to use a reaction chamber in which the deposition region is separated from the discharge region. The present invention has excellent effects, such as increasing the reaction energy on the substrate surface to promote the reaction and significantly improving the film quality.

[Brief explanation of the drawing]

Figure 1 is a schematic diagram showing the implementation state of the method of the present invention, Figure 2 (
(a) and (b) are graphs showing the comparative test results of film quality obtained by the method of the present invention and the conventional method; Fig. 3.4 is a schematic diagram showing the state of implementation of each variant of the present invention; Fig. 5. 6 are schematic diagrams showing the state of implementation of the conventional method. S... Substrate 1... Reaction chamber 2u, 2d... Upper and lower electrodes 3... High frequency power supply 4... Light source 21...
・Discharge chamber 22... Deposition chamber 23... Supply port patent Applicant Sanyo Electric Co., Ltd. Agent Patent attorney Noboru Kono Figure 4 (C) Figure 2 30 Chapter 4 ■ Hayabusa 5 Zuba et al.

Claims (1)

[Claims] 1. In the process of forming a semiconductor on a substrate by using monosilane gas, disilane gas, or a mixed gas containing at least one of them as a raw material gas and decomposing it with plasma discharge, A semiconductor manufacturing method characterized by irradiating light with a wavelength of 230 to 450 nm. 2. The semiconductor manufacturing method according to claim 1, wherein the semiconductor is an amorphous or microcrystalline semiconductor. 3. The semiconductor manufacturing method according to claim 1, wherein the irradiation light is light from a low-pressure mercury lamp having a wavelength of 253.7 nm. 4. The irradiation light has a wavelength of 230n such as K_2F, XeCl, etc.
2. The semiconductor manufacturing method according to claim 1, wherein the excimer laser beam is an excimer laser beam of m or more, or an N_2 laser beam.