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:
Jun. 08, 1976
Filed:
Nov. 18, 1974
Michael P Murphy, Flint, MI (US);
John W Riddel, Fenton, MI (US);
General Motors Corporation, Detroit, MI (US);
Abstract
A silicon solid state temperature responsive switching device having a thermally dependent P-N junction. The thermally dependent P-N junction is at the interface of a thermally invertible region and a non-invertible region. The thermally invertible region is doped with both P-type and N-type impurities. The P-type impurities have a concentration which is at least about 10 times the concentration of the N-type impurities. The P-type impurities also have an activation energy which is at least about three times the activation energy of the N-type impurities. Below a predetermined temperature, the doping effect of the N-type impurities predominates, and the invertible region is N-type. However, above the predetermined temperature, the doping effect of the P-type impurities predominates. A device insensitive to voltage source polarity is formed by sandwiching the thermally invertible region between two non-invertible regions.