METHODS OF ENHANCING DATA RETENTION OF A FLOATING GATE TRANSISTOR, METHODS OF FORMING FLOATING GATE TRANSISTORS, AND FLOATING GATE TRANSISTORS

摘要

Floating gate transistors and methods of forming the same are described. In one implementation, a floating gate is formed over a substrate. The floating gate has an inner first portion and an outer second portion. Conductivity enhancing impurity is provided in the inner first portion to a greater concentration than conductivity enhancing impurity in the outer second portion. In another implementation, the floating gate is formed from a first layer of conductively doped semiconductive material and a second layer of substantially undoped semiconductive material. In another implementation, the floating gate is formed from a first material having a first average grain size and a second material having a second average grain size which is larger than the first average grain size.