Sumitomo Sitix Corporation

Sumitomo Sitix of Amagasaki, Inc.

Setsuo Okamoto

Kaoru Kuramochi

Yoshihiro Akashi

Makoto Ito

Yasuji Tsujimoto

Kaoru Takiuchi

Takayuki Kubo

Yasunori Yoshimura

Takashi Ohnishi

Titanium target for sputtering and method of manufacturing same

A process for producing single crystals with little OSF generation and excellent dielectric strength of gate oxide films by adjusting the temperature gradient of the silicon single crystal in the direction of pulling. The process is carried out with an apparatus including a crucible which contains the melt of the single crystal material, a heating element which heats the melt, a pulling shaft to grow the single crystal, a protective gas inlet pipe, and a chamber which contains all above mentioned components. In addition, the apparatus is provided with a circular cylinder or a conical shaped heat resistant and heat insulating component below the protective gas inlet pipe. In the process of producing single crystals, the single crystal is pulled up through the circular cylinder or conical shaped heat resistant and heat insulating component below the protective gas inlet pipe, and while the pulled-up crystal is at high temperature the temperature gradient is held small and when the crystal is cooled to low temperature the temperature gradient is increased.

Process for producing single crystals

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

This invention relates to the apparatus and the process for producing single crystals with little OSF generation and excellent dielectric strength of gate oxide films by adjusting the temperature gradient of the silicon single crystal in the direction of pulling. The apparatus is provided with a crucible which contains the melt of the single crystal material, a heating element which heats the melt, a pulling shaft to grow the single crystal, a protective gas inlet pipe, and a chamber which contains all above mentioned components. In addition, the apparatus is provided with a circular cylinder or a cylindrical shaped heat resistant and heat insulating component below the protective gas inlet pipe noted above. In the process of producing single crystals, the single crystal is pulled up through the circular cylinder or a cylindrical shape heat resistant and heat insulating component below the protective gas inlet pipe, and while the palled-up crystal is at high temperature the temperature gradient in it is held small and when the crystal is cooled to low temperature the temperature gradient is increased.

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.

Growing community of inventors

Nishinomiya, Japan

Setsuo Okamoto