Patent ID: 8643123

Claim:
A method of making a semiconductor device comprising: forming a select gate dielectric layer over a semiconductor substrate; forming a select gate layer over the select gate dielectric layer; forming a select gate sidewall of the select gate layer and the select gate dielectric layer by removing at least a portion of the select gate layer and the select gate dielectric layer, wherein said removing further results in exposing a surface of the semiconductor substrate; forming a charge storage stack over at least a portion of the exposed surface of the semiconductor substrate and at least a portion of the select gate sidewall, wherein a corner portion of a top surface of the charge storage stack is non-conformal with a corner region between the select gate sidewall and the exposed surface of the semiconductor substrate, the charge storage stack comprises: a first to dielectric layer over a charge storage layer; and a second to dielectric layer over the first to dielectric layer, the second to dielectric layer is non-conformal with the first to dielectric layer, and the corner portion of the top surface of the charge storage stack has a radius of curvature measuring approximately one-third of a thickness of the charge storage stack over the substrate surface or greater; and forming a control gate layer over the charge storage stack.