Patent ID: 7294554

Claim:
A method of fabricating a semiconductor structure comprising: providing a semiconductor substrate having at least one trench opening having an aspect ratio of greater than 3.0 located therein, said at least one trench opening having sidewalls that extend to a common bottom wall by forming an arsenic-containing film within the at least one trench opening covering said sidewalls and said bottom wall, forming a first photoresist within said at least one trench opening on said arsenic-containing film, recessing said first photoresist to expose portions of the arsenic-containing film in the upper portion of the at least one trench opening, and entirely removing said arsenic-containing film from said upper portion of said at least one trench opening; providing a recessed arsenic-containing film within a bottom portion of said at least one trench opening, while maintaining the sidewalls in an upper portion of the at least one trench opening essentially free of residual arsenic; and annealing in an oxygen-containing ambient to cause outdiffusion of arsenic from said recessed arsenic-containing film into said semiconductor substrate, wherein during said annealing oxide growth within the at least one trench opening is monitored, wherein said entirely removing said arsenic-containing film from the upper portion comprises recessing said arsenic-containing film from said upper portion whereby a residual arsenic-containing film remains, forming a first dielectric cap within said at least one trench opening, forming a second recessed photoresist within said bottom portion of said at least one trench opening, and stripping said first dielectric cap and said residual arsenic-containing film not protected by said second recessed photoresist.