Patent ID: 7816211

Claim:
A method of making a semiconductor device on a semiconductor substrate, comprising: forming a first oxide layer on the semiconductor substrate for use as a gate dielectric for a high voltage transistor in a first region of the semiconductor substrate; performing decoupled plasma nitridation to the first oxide layer to form a nitrogen-rich oxide on a top surface of the oxide layer, wherein the nitrogen-rich oxide layer has a nitrogen concentration of not more than 10 atomic percent; forming a first well region in a portion of the substrate; removing a portion of the nitrogen-rich oxide layer and a portion of the first oxide layer over the first well; forming a first insulating layer, after the step of forming the oxide layer, on the well for use as a gate dielectric for a non-volatile memory transistor in and over the well; forming a charge storage layer including nanocrystals over the nitrogen-rich oxide layer and over the first insulating layer; and removing the charge storage layer including the nanocrystals over the nitrogen-rich oxide layer and adjacent to the first well using an etchant that is selective between the charge storage layer including the nanocrystals and the nitrogen-rich oxide layer so that the nitrogen-rich oxide layer functions as an etch stop layer during overetching of the charge storage layer including the nanocrystals.