Sumitomo Sitix Corporation

Sumitomo Metal Industries, Inc.

Yoshihiro Akashi

Setsuo Okamoto

Kaoru Kuramochi

Makoto Ito

Yasuji Tsujimoto

Kaoru Takiuchi

Takayuki Kubo

Yasuhiro Kogure

A method for improving the productivity when a single crystal is pulled while being mechanically held at a knob section formed at an upper end of the crystal. By controlling the crucible rotational speed, a reproducible knob section having a complex shape can be formed in a more time efficient manner than if the knob section were formed by controlling the temperature of the heater.

Method for manufacturing a single crystal

A process and apparatus for producing silicon single crystals with excellent dielectric strength of gate oxide films by adjusting the temperature gradient of the pulled-up silicon single crystal without loss of its rate of pulling. The process of producing silicon single crystals by pulling up the single crystal from a melt of material of the single crystal imposes a certain average temperature gradient on the grown single crystal while it is still at high temperature. The apparatus is provided with a heating element outside a crucible and pulling shaft with which a single crystal is pulled up from the melt of the material in the crucible. The ratio of length h of the heating element to the inside diameter .phi. of the crucible is adjusted so as to be between 0.2 and 0.8 whereby the temperature gradient can be maintained below 2.5.degree. C./mm.

Apparatus for producing single crystals

An apparatus for producing a single crystal comprising a heater which is arranged on the outer periphery of a crucible and movable along the axis of growth of a single crystal. The heater is moved along the direction of growth of the single crystal in accordance with the surface position of the molten liquid layer in the crucible. The apparatus for producing a single crystal further comprising means for adjusting the speed at which the seed crystal is pulled. For example, the pulling speed of the seed crystal is adjusted in accordance with the position of the heater.

Apparatus for producing single crystal

A solid layer is melted from the upper part thereof by the heat of a heater while the contact area between a molten liquid layer and an inner wall of a crucible is adjusted in a Double Layered CZ method, so that the eluting amount of oxygen from the crucible to the molten liquid layer is controlled. Accordingly, silicon single crystals of the low concentration of oxygen are produced.

Method of producing silison single crystal

Process for producing silicon single crystals

Method of producing single crystal

Growing community of inventors

Hyogo, Japan

Yoshihiro Akashi