Method of manufacturing a dielectric layer for a silicon-oxide-nitride-oxide-silicon (SONOS) type devices

The present invention relates generally to dielectrics for field effect semiconductor devices, and more particularly to dielectrics that may retain charge for nonvolatile insulated gate field effect transistors. A method of forming a charge storing layer is disclosed. According to an embodiment, a method may include the steps of forming a first portion of a charge storing layer with a first gas flow rate ratio (step ), forming at least a second portion of the charge storing layer by changing to a second gas flow rate ratio that is different than the first gas flow rate ratio (step ), and forming at least a third portion of the charge storing layer by changing to a third gas flow rate ratio that is different than the second gas flow rate ratio (step ).