METHOD FOR DIFFERENTIAL FIELDOX GROWTH

摘要

A local oxidation of silicon (LOCOS) process directed to forming differential field oxide thickness on a single wafer in one patterning step and one growth step. When patterning the masking layer, at least two window widths are formed in the masking layer, exposing the underlying substrate and pad oxide. When one of the window widths is sufficiently small, oxidation of the substrate will be inhibited causing reduced growth and thus a reduced field oxide thickness in that window as compared to other larger windows formed in the same masking layer, creating differential field oxide thicknesses in one growth step.