Kaoru Kuramochi

US Patent:

56118570, Mar 18, 1997

Filed:

Jun 7, 1995

Appl. No.:

8/474662

Inventors:

Yoshihiro Akashi - Kobe, JP
Kaoru Kuramochi - Montgomery OH
Setsuo Okamoto - Nishinomiya, JP
Yasuji Tsujimoto - Kobe, JP
Makoto Ito - Saga, JP

Assignee:

Sumitomo Sitix Corporation - Amagasaki

International Classification:

C30B 3500

US Classification:

117217

Abstract:

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.

US Patent:

55758479, Nov 19, 1996

Filed:

Nov 8, 1994

Appl. No.:

8/337474

Inventors:

Kaoru Kuramochi - Montgomery OH
Setsuo Okamoto - Nishinomiya, JP

Assignee:

Sumitomo Sitix Corporation - Amagasaki

International Classification:

C30B 3500

US Classification:

117210

Abstract:

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.

US Patent:

56835051, Nov 4, 1997

Filed:

Feb 27, 1996

Appl. No.:

8/607401

Inventors:

Kaoru Kuramochi - Montgomery OH
Setsuo Okamoto - Nishinomiya, JP

Assignee:

Sumitomo Sitix Corporation - Amagasaki

International Classification:

C30B 1520

US Classification:

117 34

Abstract:

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.

US Patent:

54740193, Dec 12, 1995

Filed:

Oct 13, 1994

Appl. No.:

8/322197

Inventors:

Yoshihiro Akashi - Kobe, JP
Kaoru Kuramochi - Montgomery OH
Setsuo Okamoto - Nishinomiya, JP
Yasuji Tsujimoto - Kobe, JP
Makoto Ito - Saga, JP

Assignee:

Sumitomo Sitix Corporation - Amagasaki

International Classification:

C30B 1534

US Classification:

117 1

Abstract:

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.