JPH0620054B2 - Thin film formation method - Google Patents

Description

TECHNICAL FIELD The present invention relates to silicon epitaxy, and more particularly to a thin film forming method for selectively growing silicon.

(Prior Art) FIG. 2 shows a conventional process of silicon selective epitaxy. In FIG. 2 (1), the nitride film 2 is formed on the substrate 21.
2 is formed, and a mask 23 such as a resist is further formed by light or electron beam exposure method (FIG. 2 (1)). Next, using the mask 23, the nitride film 22 is etched by CF ₄ reactive ion etching (FIG. 2 (2)). After that, the resist is removed by oxygen plasma (FIG. 2 (3)). In this way, a nitride film pattern is formed on the silicon substrate. Then, silicon selective epitaxy is performed in which silicon is grown only on silicon and silicon is not grown on the nitride film by gas reactive vapor deposition using a dichlorosilane source.

(Problems to be Solved by the Invention) However, this conventional method has a drawback that the steps are complicated. It is an object of the present invention to provide a thin film forming method by a silicon selective epitaxy method in which the process is simplified by selective ion implantation.

(Means for Solving Problems) According to the present invention, a step of forming silicon nitride in a portion where ion implantation is performed by performing ion implantation of nitrogen into a predetermined region on a silicon substrate, and then the silicon nitride Is a method for forming a thin film, which comprises a step of performing silicon epitaxy on a region where no film is formed.

(Operation) The principle and operation of the present invention will be described. In the field of ion implantation, there is a technique for surface modification by implanting ions into a substrate. For example, by implanting nitrogen ions into a silicon substrate, the substrate surface can be made into silicon nitride (SiNx). Here, the value of x can be controlled by the ion implantation amount of nitrogen. Further, the ion implantation depth can be controlled by the ion acceleration energy at the time of ion implantation. In this way, by the surface modification technology by ion implantation,
It is possible to form silicon nitride on a silicon substrate. By implanting nitrogen ions into the silicon substrate, the silicon nitride layer can be selectively formed on the silicon substrate. From this, by selective ion implantation of nitrogen, a silicon nitride layer is selectively formed on the silicon substrate, and selective epitaxy of silicon becomes possible.

Example An example of the present invention will be described below with reference to FIG. In FIG. 1 (1), a mask 12 such as a resist is formed on the substrate 11.
Are formed by a light or electron beam exposure method (FIG. 1 (1)).
Next, ion implantation is performed on the silicon substrate 11 by the nitrogen ion beam 13. Here, acceleration energy 200ke
A nitrogen ion beam with V and a dose of 1 × 10 ¹⁸ / cm ² was used.
In this way, the nitrogen ion implantation region 13 is formed (first
Figure 2)). Next, the mask 12 is removed (FIG. 1 (3)). In this way, the silicon nitride layer is selectively formed by nitrogen ion implantation. Next, selective epitaxy in which silicon does not grow only in a region (silicon nitride) into which nitrogen ions are implanted can be performed by a gas reactive vapor deposition method using dichlorosilane (FIG. 1 (4)). In this example, 200 keV acceleration energy was used, but since selective epitaxy utilizes the difference in surface energy, ion implantation may be performed at a lower energy. The dose is 1 × 10 ¹⁷ / cm ² or more 1 × 10
The range is ²⁰ / cm ² .

(Effects of the Invention) As described above, according to the thin film forming method of the present invention, nitrogen ion implantation is performed on a silicon substrate to selectively form a silicon nitride layer, and selective epitaxy is performed to simplify the process. It is possible to form a thin silicon film.

[Brief description of drawings]

FIG. 1 is a partial sectional view schematically showing an embodiment of the present invention, and FIG. 2 is a sectional view showing a conventional silicon selective epitaxy method. 11,21: Si substrate, 12,23: Mask, 14,23: Si epitaxial thin film, 13: Implanted region

Claims (1)

[Claims] 1. A step of implanting nitrogen ions into a predetermined region of a silicon substrate to form silicon nitride in the ion-implanted portion, followed by silicon implantation in the region where the silicon nitride film is not formed. A thin film forming method including at least a step of performing epitaxy.