The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jan. 20, 1976
Filed:
Mar. 09, 1973
Krishan S Tarneja, Pittsburgh, PA (US);
John Bartko, Pittsburgh, PA (US);
Joseph E Johnson, Pittsburgh, PA (US);
Westinghouse Electric Corporation, Pittsburgh, PA (US);
Abstract
Diodes of a particular type are fine tuned with irradiation to optimize the reverse recovery time while minimizing forward voltage drop and providing more uniform electrical characteristics. The initial and desired minority carrier lifetimes in the anode region of the type are determined as a function of forward voltage drop and reverse recovery time, and the minority carrier radiation damage factor is determined for a desired type of diode and radiation source. The radiation dosage to achieve the desired carrier lifetime with the radiation source is thereafter determined from the function 1/.tau. = 1/.tau..sub.o + K.phi., where .tau. is the desired minority carrier lifetime, .tau..sub.o is the initial minority carrier lifetime, K is the determined minority carrier radiation damage factor and .phi. is the radiation dosage. A major surface and preferably the major surface adjoining the anode region of the diodes is then irradiated with the radiation source to the determined radiation dosage. Preferably, the radiation dosage is between about 1 .times. 10.sup.12 and 5 .times. 10.sup.13 e/cm.sup.2, with electron radiation of intensity between 1 and 3 Mev.