Naoetsu Electronics Co., Ltd.

Shin-etsu Chemical Co., Ltd.

Shin-etsu Handotai Co., Ltd.

Takeshi Akatsuka

Masatoshi Takahashi

Takenori Watabe

Hiroyuki Ohtsuka

Junichi Okada

Naoki Ishikawa

Satoyuki Ojima

Tsutomu Sato

Toyohiro Ueguri

Shigenori Saisu

Yasushi Yoshimura

Tsutomu Onishi

Shunichi Igarashi

The present invention can finely arrange p-type diffusion layers and n-type diffusion layers. A p-type diffusion layerand an n-type diffusion layerare simultaneously formed on a back surfaceof a semiconductor substratein a state that the p-type diffusion layerand the n-type diffusion layerare arranged close to each other, and a back surfaceside of the semiconductor substrateon which outer end portions of the p-type diffusion layersand the n-type diffusion layersare brought into contact with each other is removed thus separating the p-type diffusion layerand the n-type diffusion layerfrom each other and hence, the p-type diffusion layerand the n-type diffusion layercan be separately arranged in a state that the p-type diffusion layerand the n-type diffusion layerare arranged close to each other.

Back junction solar cell and process for producing the same

An efficient method is proposed for the preparation of a silicon single crystal wafer for discrete semiconductor devices, such as transistors, deeply doped with a dopant on one surface, the other surface being mirror-polished. Different from the conventional process in which a single base wafer is subjected to a deposition doping and drive-in doping treatments to form a deeply doped layer on each of the surfaces followed by removal of one of the doped layers and lapping and mirror-polishing the surface, the improvement of the invention can be obtained by subjecting a base wafer having an increased thickness to the deposition and drive-in doping treatments to form deeply doped layers on both surfaces leaving an undoped layer in-between followed by slicing this base wafer by using an annular slicing blade having a thickness specifically correlated to the thickness of the starting wafer along the undoped layer into two separate wafers each having a laminar structure consisting of a doped layer and an undoped layer which are each lapped and mirror polished on the surface of the undoped layer.

Method for the preparation of discrete substrate plates of semiconductor

In a method of preparing a diffused silicon device substrate for use in the fabrication of a MOS power device, a drive-in diffusion step is followed by a thermal donor formation heat treatment which is achieved by heating the silicon device substrate at a temperature from 400.degree. to 500.degree. C. for 1 to 20 hours and in a gas atmosphere containing oxygen gas, and subsequently a thermal donor formation retarding heat treatment is performed by heating the silicon device substrate at a temperature of from 600.degree. to 700.degree. C. for 8 to 24 hours in a gas atmosphere containing oxygen gas.

Method of preparing diffused silicon device substrate

Growing community of inventors

Niigata, Japan

Takeshi Akatsuka