Scaling effects of single-event gate rupture in thin oxides

Abstract

The dynamics of the excess carriers generated by incident heavy ions are considered in both SiO2 and Si substrate. Influences of the initial radius of the charge track, surface potential decrease, external electric field, and the LET value of the incident ion on internal electric field buildup are analyzed separately. Considering the mechanisms of recombination, impact ionization, and bandgap tunneling, models are verified by using published experimental data. Moreover, the scaling effects of single-event gate rupture in thin gate oxides are studied, with the feature size of the MOS device down to 90 nm. The value of the total electric field decreases rapidly along with the decrease of oxide thickness in the first period (12 nm to 3.3 nm), and then increases a little when the gate oxide becomes thinner and thinner (3.3 nm to 1.8 nm).