JPH02214115A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To eliminate deterioration of contact characteristic by a method wherein an amorphous silicon layer is formed, by a heat treatment, on another polysilicon layer united to a polysilicon layer and a contact between the polysilicon layer and a silicon single-crystal substrate is formed in a contact- formation region. CONSTITUTION:An amorphous silicon layer 4 is applied to and formed on an insulating film 2 and a contact-formation region 3 by a CVD operation; in addition, a polysilicon layer 5 is applied to and formed on the amorphous silicon layer 4 by the CVD operation. After that, a heat treatment is executed; the amorphous silicon layer 4 is transformed into a polysilicon layer; a polysilicon layer 6 united to the polysilicon layer 6 is formed; a contact between the layer and a silicon single crystal of a silicon single-crystal substrate 1 is formed in the contact-formation region 3. Thereby, a P-N junction reverse-current value in the contact-formation region 3, i.e., a leakage current value, can be suppressed by one digit or above as compared with ordinary cases.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method of manufacturing a semiconductor device that forms good contact between a silicon substrate and a polysilicon layer.

(Prior Art) FIG. 2 is a process cross-sectional view showing a conventional method for manufacturing a semiconductor device.

In the conventional manufacturing method, first, as shown in FIG. 2(a), an insulating film 22 is formed on a silicon single crystal substrate 21, and a contact forming region 23 is formed by selectively photoetching the insulating film 22 to open it. Thereafter, as shown in FIG. 2(b), a polysilicon layer 24 is deposited on the entire surface by CVD, and a contact between the silicon single crystal substrate 21 and the polysilicon layer 24 is formed by further heat treatment. was.

(Problems to be Solved by the Invention) However, in the above-mentioned conventional manufacturing method, as shown in FIG.
), crystal defects were generated in the region 25 shown in ), resulting in deterioration of contact characteristics.

This is because the crystal structure within the polysilicon layer 24 is destroyed by the heat treatment, causing strain within the silicon single crystal, particularly in the contact formation region 23.

An object of the present invention is to provide a method for manufacturing a semiconductor device that eliminates the deterioration of contact characteristics as described above.

(Means for Solving the Problems) The present invention achieves the above-mentioned object in manufacturing a semiconductor device by forming an insulating film on the surface of a silicon single crystal substrate and selectively etching the insulating film to form an opening and making contact. After that, an amorphous silicon layer and a polysilicon layer are successively deposited on the entire upper surface including the insulating film, and heat treatment is performed on the amorphous silicon layer to form another layer integral with the polysilicon layer. This is achieved by forming a polysilicon layer and forming a contact between the formed polysilicon layer and the silicon single crystal substrate in the contact formation region.

(Function) According to the present invention, during heat treatment, the amorphous silicon layer starts solid phase epitaxial growth without preserving the crystal axis of the underlying single crystal, and provides a buffer against destruction of the crystal structure within the polysilicon layer. It acts as a layer to initiate polysiliconization and ultimately forms a single polysilicon layer. Therefore, contact defects as described above are eliminated, and a semiconductor device with stable characteristics is manufactured.

(Example) An example of the present invention will be described below using the manufacturing process cross-sectional diagram of FIG. 1.

In the manufacturing method of the present invention, first, as shown in FIG. 1(a), an insulating film 2 is formed on the surface of a silicon single crystal substrate, and an opening is formed by selectively photoetching the insulating film 2. is defined as a contact formation region 3.

Next, as shown in FIG. 2B, an amorphous silicon layer 4 is deposited on the insulating film 2 and the contact formation region 3 by CVD at a temperature of 550°C.

Furthermore, as shown in the same figure (0), temperature 62
A polysilicon layer 5 is formed on the amorphous silicon layer 4 at 0° C., and then heat treatment is performed at 900° C. to convert the amorphous silicon layer 4 into a polysilicon layer. A contact between the silicon layer 6 and the silicon single crystal of the silicon single crystal substrate 1 is formed in the contact formation region 3 .

Although the present invention forms a contact as described above, the PN junction reverse current value, that is, the leakage current value in the contact forming region can be suppressed by more than one order of magnitude compared to the conventional method.

(Effects of the Invention) As is clear from the above, according to the present invention, a contact between a silicon single crystal and a polysilicon layer without crystal defects can be easily formed, and therefore a semiconductor device with good contact characteristics can be obtained. The effect of manufacturing with high yield can be achieved.

[Brief explanation of the drawing]

FIG. 1 is a process sectional view showing an embodiment of the present invention, and FIG. 2 is a process sectional view explaining a conventional manufacturing method. 1...Silicon single crystal substrate, 2...Insulating film. 3... Contact formation region, 4... Amorphous silicon layer. Layer 5.6...Polysilicon patent applicant Matsushita Electronics Co., Ltd.

Claims (1)

[Claims] In the manufacture of semiconductor devices, an insulating film is formed on the surface of a silicon single crystal substrate, and an opening is formed by selectively etching it to form a contact formation region.
An amorphous silicon layer and a polysilicon layer are sequentially deposited on the entire upper surface including the insulating film, and heat treatment is performed on the amorphous silicon layer to form another polysilicon layer integral with the polysilicon layer. A method of manufacturing a semiconductor device, comprising forming a contact between the formed polysilicon layer and the silicon single crystal substrate in the contact formation region.