Projected Life-Times of Circuits in Krypton 85 Contaminated Packages

Abstract

This article presents a Monte Carlo model which calculates the radiation dose absorbed by the oxide layers on the chip from the radioactivity level in a package. The simulation allows one to obtain the time of failure of a given circuit, based on the initial activity in the package and the radiation hardness of the circuit. The model includes the effects of (3-particle energy spectrum, package geometry, electron backscattering, and beta absorption through layers of various materials on the chip. Our simulation shows that the levels of Kr85 contamination assumed to be harmless in the literature may in fact cause long term failures in some memories in typical hermetically-sealed ceramic packages. Copyright © 1982 by The Institute of Electrical and Electronics Engineers, Inc.