Abstract: A method of forming round corners for a gate oxide between a floating gate and a control gate of a memory cell comprises the steps of forming the floating gate over a tunnel oxide; forming a mask over the floating gate; forming rounded end caps adjacent distal ends of the mask; transferring the rounding of the end caps to top corners of the floating gate; forming the gate oxide over the floating gate; and, forming the control gate over the gate oxide. A memory cell having a rounded corner interface between the floating gate and control gate is also provided.

Abstract: A method of shallow trench isolation by forming a trench in a semiconductor device comprises the steps of forming an oxide layer; forming a mask layer; anisotropically etching the mask layer; forming a second oxide layer; forming a cap layer; forming rounded end caps adjacent the mask; and transferring the rounding of the caps to the top corners of the trench. The oxide layer is formed over a substrate of the semiconductor device. The mask layer is formed over the oxide layer. The mask layer is then anisotropically etched to form the mask and an opening in the mask. The opening in the mask exposes the substrate, and the width of the opening is greater than the width of the trench. Blanket etching the cap layer forms the rounded end caps. The rounded end caps are adjacent to the mask on opposite ends of the opening, and the distance between the end caps is about equal to the width of the trench. The trench is formed by plasma etching the trench.