Nippon Steel Corporation

Mitsubishi Materials Corporation

Research Development Corporation of Japan

Toshiba Ceramics Co., Ltd.

Komatsu Electronic Metals Co., Ltd.

Sumitomo Sitix Corporation

Nsc Electron Corporation

Wacker Nsce Corporation

Atsushi Ikari

Shigeyuki Kimura

Hitoshi Sasaki

Souroku Kawanishi

Koji Izunome

Shinji Togawa

Atsuki Matsumura

Isao Hamaguchi

Keisuke Kawamura

Tsutomu Sasaki

Wataru Ohashi

Yoshiharu Inoue

Koki Tanaka

Takayuki Yano

Shunichi Hayashi

Yoichi Nagatake

Toshio Iwasaki

Shin-ichi Fujimoto

Hiroshi Isomura

Takayoshi Ishida

Michiharu Tamura

Masami Hasebe

Katsuhiko Nakai

Hikaru Sakamoto

Taizo Hoshino

The present invention provides a wafer holder, a wafer support member, a wafer boat and a heat treatment furnace, which are capable of sufficiently suppressing slip dislocations, without lowering productivity and at low cost, in the high temperature heat treatment of silicon wafers, and said wafer holder is characterized in that: the wafer holder is composed of a wafer support plate and three or more wafer support members mounted on said wafer support plate, each of the wafer support members having a wafer support portion or more; at least one of said wafer support members is a tilting wafer support member which has a plurality of upward-convex wafer support portions on the upper surface and is tiltable with respect to said wafer support plate; and the wafer is supported by at least four wafer support portions.

Wafer holding, wafer support member, wafer boat and heat treatment furnace

A SOI substrate of high quality which allows LSI to be formed thereon in an improved yield and realizes excellent electric properties and a method for the production thereof are provided. The SOI substrate is obtained by forming an embedded oxide layer on a silicon single crystal substrate and forming a SOI layer for the formation of a device on the embedded oxide layer and is characterized by the SOI layer containing pit-like defects at a density of not more than 5 cm or the embedded oxide layer containing pinhole defects at a density of less than one piece/cm .

SOI substrate and method for production thereof

A silicon semiconductor substrate is obtained by deriving a silicon semiconductor substrate from a silicon single crystal grown by the Czochralski method from a molten silicon containing not less than 1&times;10 atoms/cm and not more than 1.5&times;10 atoms/cm of nitrogen and heat-treating the silicon semiconductor substrate at a temperature of not less than 1000&deg; C. and not more than 1300&deg; C. for not less than one hour and is characterized by the fact that the density of crystal defects measuring not less than 0.1 &mgr;m as reduced to diameter is not more than 10 pieces/cm at least in the region reaching a depth of 1 &mgr;m from the surface of the substrate and the nitrogen content at the center of thickness of the silicon semiconductor substrate is not less than 1&times;10 atoms/cm and not more than 1&times;10 atoms/cm .

Silicon semiconductor wafer and method for producing the same

This invention is directed to a method for the production of a dislocation-free silicon single crystal by the Czochralski method. This method attains growth of the main body part of the dislocation-free silicon single crystal by immersing a seed crystal in a melt of silicon and then pulling the seed crystal without recourse to the necking. The seed crystal thus used is a dislocation-free silicon single crystal. The horizontal maximum length of the part of the seed crystal being immersed in the melt at the time of completing the immersion of the seed crystal in the melt is not less than 5 mm. The immersing rate of the seed crystal in the melt is not more than 2.8 mm/min and the part of the seed crystal to be immersed in the melt is a crystal as grown.

Method for production of dislocation-free silicon single crystal

When a Si single crystal 8 is pulled up from a melt 6 received in a crucible 2, the state of eddy flows generated in the melt 6 is judged from the temperature distribution of the melt at the surface. According to the result of judgement, the gas, i.e. N.sub.2, Xe or Kr, which causes extraoridnary deviation in the density of a melt 6 is added to an atmospheric gas, so as to keep the eddy flows under unstabilized condition. The effect of said gas is typical in the case of crystal growth from the melt to which a dopant such as Ca, Sb, Al, As or In having the effect to suppress the extraordinary deviation in the density is added. Since the single crystal is pulled up from the melt held in the temperature-controlled condition at the surface, impurity distribution and oxygen distribution are made uniform along the direction of crystal growth. A single crystal obtained in this way has highly-stabilized quality.

Growth of silicon crystal from melt having extraordinary eddy flows on

When a B or P-doped Si single crystal is pulled up from a B or P-doped melt by the Czochralski method, an element such as Ga, Sb or In having the effect to reduce the heat expansion coefficient of said melt at a temperature near the melting point is added to said melt. The additive element stabilizes the temperature condition of crystal growth so as to control the generation of eddy flows just below the interface of crystal growth. When a Ga or Sb-doped Si single crystal is pulled up from a Ga or Sb-doped melt, an element such as B or P having the effect to increase the heat expansion coefficient of said melt at a temperature near the melting point is added. The agitation of the melt just below the interface of crystal growth is accelerated by the addition of B or P, so as to assure the growth of a Si single crystal from the melt having impurity distribution made uniform along the radial direction. Accordingly, a Si single crystal is formed having a uniform impurity distribution along its lengthwise or radial direction.

Growth of silicon single crystal having uniform impurity distribution

When a single crystal is pulled up from a melt, the difference .DELTA.T between temperatures at the bottom of a crucible and at the interface of crystal growth is controlled so as to hold the Rayleigh constant defined by the formula of:

Growth of silicon single crystal

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Tsukuba, Japan

Atsushi Ikari