Effects of electric fields on annealing of radiation damage in MOSFET's

Abstract

Radiation damage in <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">p</tex> -channel MOS devices by 1.5 MeV electrons has been studied by thermal annealing in conjunction with electric fields between the metallic gate and the substrate. Both positive and negative gate biases retard the process of annealing. Annealing with negative gate bias reveals 1) that during thermal annealing the majority of the electrons that recombine with the positive charge in the oxide originate from the conduction band of the silicon, and 2) that during irradiation a great number of ionized electrons that remain in the oxide do not recombine with the holes, but are trapped in weakly bound states. The effect of positive bias on annealing of radiation damage is obscured by the positive charge induced due to positive bias-temperature treatment alone. No effect of drain-to-source potential on annealing has been observed.