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:
Apr. 07, 1992
Filed:
Dec. 13, 1990
Anthony L Caviglia, Laurel, MD (US);
Andras F Cserhati, Columbia, MD (US);
John B McKitterick, Columbia, MD (US);
Allied-Signal Inc., Morris Township, Morris County, NJ (US);
Abstract
Means for compensating for threshold voltage shifts of Metal Oxide Semiconductor Field Effect Transistors (MOS FETs) of a Large Scale Integrated Circuit device (LSI), where the threshold voltage shifts are induced by radiation dosage. The FETs are formed in a relatively thin layer of silicon on an insulator film supported by a substrate. The compensating means includes a pair of sensor FETs formed integrally with the LSI device, an operational amplifier and a back gate formed opposite the channel regions of the FETs of the LSI device. The sensor FETs develop an output voltage that is applied as one input to the operational amplifier. A reference voltage, equal to the sensor output voltage prior to exposure to radiation, is applied as a second input to the operational amplifier. The amplifier output is applied to the back gate. The sensor output voltage changes as a result of radiation dosage. The amplifier output then changes, altering the back gate voltage in a manner tending to restore the sensor output to the original value. Such change in the back gate voltage compensates for radiation induced changes in the threshold voltages of the FETs of the LSI device.