Methods of filling gaps by deposition on materials having different deposition rates

摘要

Methods of forming material in a gap in a substrate include forming a pattern to define a gap on a substrate. A bottom oxide layer is formed on a surface of the substrate and substantially filling the gap. The bottom oxide layer is etched back inside an opening in the gap to expose side walls of the gap so that a residual bottom oxide layer remains at a bottom of the gap. A top oxide layer is selectively deposited on the residual bottom oxide layer, wherein the top oxide layer is deposited in a first direction toward the opening at a faster rate than in a second direction away from the side walls.