Patent ID: 8871645

Claim:
A method of shaping a material layer, comprising: (a) oxidizing a surface of a material layer of a semiconductor substrate having a tunnel oxide layer and a shallow trench isolation region disposed adjacent to the tunnel oxide layer to form an oxide layer at a first initial rate, wherein the material layer is a floating gate that comprises polysilicon, silicon or a metal and is disposed above the tunnel oxide layer; (b) terminating formation of the oxide layer after a predetermined period of time that corresponds to an oxidation rate of about 90% or below of the first initial rate such that oxygen diffusion into exposed oxide layers disposed beneath the material layer is substantially avoided; (c) removing the oxide layer by an etching process to provide a fresh exposed surface of the material layer that can further be oxidized at a new initial rate that is substantially equivalent to the first initial rate; and (d) repeating (a) through (c) until the material layer is formed to a desired shape, wherein subsequent iterations of oxidizing the surface of the material layer form the oxide layer at the new initial rate.