Nonuniform total-dose-induced charge distribution in shallow-trench isolation oxides

Abstract

A new approach for modeling the radiation-induced charge distribution in shallow-trench isolation (STI) structures shows that much less charge is trapped near the top of the trench. We found that charges inside the STI oxide are pushed down by the vertical electric field coming from the positive gate bias, leaving much less total-dose-induced charge close to the top of trench. This nonuniformity significantly affects the measured leakage current.