Freeze-out characterization of radiation hardened N/sup +/ polysilicon gate CMOS transistors

Abstract

Freeze-out behavior of radiation hardened N+ polysilicon gate CMOS devices is studied at liquid-nitrogen temperature before and after irradiation at different dose levels. Explanations are given for the threshold voltage variations and freeze-out effects both before and after irradiation. The degree of freeze-out of the counterdope implant is controlled by temperature, applied gate potential, and applied body-to-source potential. Based on experimental results of this work, freeze-out is not significantly affected by irradiation doses, or the magnitude of the gate bias during radiation.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>