Modeling of charge-injection effects in metal-oxide-semiconductor structures

Abstract

A recently published dynamic balance model which describes gate-oxide degradation following prolonged charge injection is modified. This modification replaces the average electric field in the oxide with the electric field spatial distribution. It is shown that a very close interchangeable relationship exists between the electric field spatial distribution and the spatial distributions of the trapped charge and generated trapping sites. The validity of the new modified model is confirmed for different oxide thicknesses (130–720 Å), injection techniques (hot-electron injection and constant current-tunneling injection), and gate electrode material (aluminum versus polycrystalline silicon). The most attractive feature of the modified dynamic balance model is its ability to describe the steady-state occupation level changes for any given electric field following any oxide stress injection. Furthermore, the modified model is used to propose a new breakdown model which is described in a companion paper.