Non-volatile memory device with improved data retention and method therefor

Abstract

A semiconductor device () comprises an underlying insulating layer (), an overlying insulating layer () and a charge storage layer () between the insulating layers (). The charge storage layer () and the overlying insulating layer () form an interface, where at least a majority of charge in the charge storage layer () is stored. This can be accomplished by forming a charge storage layer () with different materials such as silicon and silicon germanium layers or n-type and p-type material layers, in one embodiment. In another embodiment, the charge storage layer () comprises a dopant that is graded. By storing at least a majority of the charge at the interface between the charge storage layer () and the overlying insulating layer (), the leakage of charge through the underlying insulating layer is decreased allowing for a thinner underlying insulating layer () to be used.