Thomas C Joseph

US Patent:

59869500, Nov 16, 1999

Filed:

Oct 15, 1997

Appl. No.:

8/950780

Inventors:

Thomas Wesley Joseph - Wappingers Falls NY

Assignee:

International Business Machines Corporation - Armonk NY

International Classification:

G11C 700

US Classification:

365200

Abstract:

To improve both the yield and the reliability of manufactured integrated circuits incorporating redundancy circuits, unused redundancy circuits are additionally used to bracket a defective circuit or circuits identified through production testing by replacing adjacent circuits which have tested satisfactorily and which would otherwise not be replaced, but which are considered to be prone to subsequent failure.

US Patent:

59077778, May 25, 1999

Filed:

Jul 31, 1997

Appl. No.:

8/903671

Inventors:

Thomas W. Joseph - Wappingers Falls NY
Christopher C. Parks - Beacon NY

Assignee:

International Business Machines Corporation - Armonk NY

International Classification:

H01L 218234

US Classification:

438275

Abstract:

The preferred embodiment provides a method for fabricating field effect transistors that have different threshold voltages without requiring excessive masking and other fabrication steps. In particular, the method facilitates the formation of FETs with different threshold voltages by doping the gate dielectric with various amounts of ions. This provides a built in potential in the gate dielectric proportional to the amount of ions in the gate dielectric. This potential changes the threshold voltage of the FET. Thus, by selectively doping the gate dielectric with ions the threshold voltage of a FET can be changed. The selective doping of many FETs to many different threshold voltages can be done with only one additional masking step. Thus, the present invention provides the ability to form FETs having different threshold voltages without requiring excessive process complexity.