SWITCHING OXIDE TRAPS

Abstract

Positive oxide trapped charge is one of the main factors determining the radiation response of a CMOS device. The most widely accepted model for oxide-trapped charge is the dipole model, originally proposed by Lelis et al. The annealing of radiation-induced positive trapped charge proceeds (usually) via the tunneling of electrons, which form metastable dipoles, compensating the trapped positive charge without removing it. Under appropriate bias, these compensating electrons can tunnel back to the Si substrate, restoring the trapped positive charge. The experimental work leading to the development of this model is summarized. By now there is a large body of experimental and theoretical work by others, confirming and extending the original model. In particular, the relevance of the model to some electron trapping studies has been shown, and its application to the larger topic of oxide reliability is discussed.