JPS5935015A - Preparation of silicon film - Google Patents

Abstract

PURPOSE:To form a silicon film having a uniform distribution and small electric resistance on a substrate, by making a silicon film in a hydrogen-containing inert gas atmosphere by sputtering method, heat-treating it. CONSTITUTION:In the preparation of silicon film wherein silicon is applied from the target 3 set on the electrode 2 to the substrate 5 on the base 4 arranged in the container 1 by sputtering, it is then heat-treated at 800-1,200 deg.C, an inert gas containing 0.5-50% hydrogen is used as an atmospheric gas in the container 1 instead of a single inert gas (e.g., argon).

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of manufacturing a silicon film by sputtering, which has low electrical resistance and uniform distribution.

Conventionally, the vapor phase growth method has been most widely used to manufacture silicon films used as electrodes and wiring in semiconductor devices such as H40S or bipolar. However, as a method for manufacturing this silicon film, a sputtering method is also used, which has the characteristic of being able to perform low-temperature processing.

The production of a silicon film by sputtering (hereinafter abbreviated as sputtering) is carried out in an inert gas such as argon using an apparatus whose main parts are shown in FIG. That is, when an inert gas such as argon is introduced into the sputtering container 1 at a predetermined pressure and a negative voltage or high frequency voltage is applied to the electrode 2 to cause discharge, the target 6 made of silicon fixed to the electrode 2 is A substrate 5 whose surface has been sputtered and is held on a substrate support 4 facing a target 6
A silicon film is formed on the surface. In this case, the target used is one containing impurity atoms such as l-', As, or B to lower the electrical resistance, or a target made of simple silicon. In the latter case, impurity atoms are introduced into the silicon film using ion implantation or the like. The silicon film formed as described above is subjected to heat treatment to lower its electrical resistance and used as electrodes and wiring in semiconductor devices.

Figure 2 shows the change in sputtering gas pressure of the silicon film formed using the conventional method described above, that is, in a simple inert gas such as argon, and Figure 3 shows the change in resistance with respect to the position on the wafer. Shown below. These values are 8 for the target
"φ (203, 21 former ηφ) with a purity of 99.9999% was used, the distance between the target and the substrate was 39 mm, and the background pressure was approximately 3 × 10' 1.
”o+°1, 4”φ(101,61
1011φ) sea urchin…” Second, magnetron It
I'''' sputtering equipment, thickness 0.57Al11
After the deposition, P is introduced by the ion corporation method, and then,
These are the results when heat treatment was performed at 1000° C. for 20 minutes in a N2 atmosphere. As shown in FIG. 2, the 7-t resistance is significantly dependent on the sputter gas pressure, and unless the sputter gas pressure is strictly controlled, the resistance will be poor; /j 'l! 11'l is in
I can't. However, as shown in FIG. 6, the distribution of characteristics is not uniform and is limited only to the center of the film where the sheet resistance is small.

As shown in Figure 2 below, if a single inert gas such as argon is used in the conventional method, only the 7 licon film in the center of the wafer can be used, resulting in poor productivity and high manufacturing costs for semiconductor devices. However, since the sputtering gas pressure must be strictly controlled, there are drawbacks such as the sputtering apparatus being complicated to handle.

The purpose of the present invention is to eliminate the drawbacks of the above-mentioned conventional methods, and to form a silicon film with low electrical resistance using an extremely simple method.
An object of the present invention is to provide a method for manufacturing a silicon film that can be manufactured over the entire surface of a wafer.

The method for producing a silicon film according to the present invention, which achieves the above purpose, is characterized by the step of forming a silicon film by a sputtering method in an inert gas containing 0.5 to 50% hydrogen; and heat treating the film at a temperature in the range of 800°C to 1200°C. According to the present invention, in an extremely simple method,
A silicon film with low electrical resistance can be formed over the entire surface of the wafer.

EXAMPLES The present invention will be specifically explained in detail below using Examples.

Using the apparatus shown in Fig. 1 described above, using a sputtering gas containing 50% hydrogen mixed with argon, and other conditions being the same as when obtaining the results shown in Figs. 2 and 6 above, We fabricated a silicon film and investigated its properties.

As a result, the sputtering gas pressure dependence of the /-t resistance is
The dependence of sheet resistance on spuck gas pressure is as shown in the figure, and the dependence of sheet resistance on argon alone (second
(see figure), and the sheet resistance value was also reduced. It's a trench, 4"φ (101,6...
mφ) Sea urchin... The sheet resistance distribution on the surface was as shown in FIG. 5, and the sheet resistance was uniform over the entire wafer surface.

However, the change in root resistance due to the amount of hydrogen mixed in the sputtering gas was investigated by fabricating a silicon film under the same conditions as in the above example and examining its characteristics by varying the amount of hydrogen mixed in the sputtering gas. However, the results shown in Figure 6 were obtained. Suwachi, 0.5%
If it is smaller than 50%, the effect of hydrogen is not recognized, and if it is larger than 50%, it becomes worse again. Therefore, the appropriate amount of hydrogen to mix is 0.
They are in charge of 5 to 50.

Furthermore, similar effects were observed when hydrogen was mixed with an inert gas other than argon used in the above examples, such as neon, xenon, or krypton.

As explained above, according to the present invention, a silicon film having low electrical resistance can be uniformly obtained over the entire surface of the substrate, thereby significantly improving productivity and reducing the manufacturing cost of semiconductor devices. However, since the dependence of electrical resistance on sputtering gas pressure is reduced, there are advantages such as significantly easier production of silicon films.

[Brief explanation of the drawing]

FIG. 1 is an explanatory cross-sectional view of a main part of a standard sputtering apparatus. FIGS. 2 and 6 are graphs showing the dependence of the sheet resistance of a silicon film 17 manufactured by a conventional method on sputtering gas pressure and its distribution on a wafer. FIGS. 4 and 5 are graphs showing the sputtering gas pressure dependence and the distribution on the sea urchin of the sheet resistance of the silicon film manufactured by the manufacturing method of one embodiment of the present invention. Figure 6 shows the amount of hydrogen mixed into the sputtering gas and /
-I is a graph showing the relationship between resistance. Intestinal 1 ¥ 1 Deda Human Equal Hongen Telecommunications Corporation Junnosuke Nakaritaro Figure 1, 12 Fig. 12, ・ ・ Riki ゛ ス り り り − − − − − − − − −））））） Standing ((tn)

Claims (1)

[Claims] The method comprises a step of forming a silicon film by sputtering in an inert gas containing 0.5% to 50% hydrogen, and a step of heat-treating the silicon film at a temperature in the range of 800°C to 1200°C. A method for manufacturing a silicon film characterized by the following.