Multiple thickness semiconductor-on-insulator field effect transistors and methods of forming the same

Abstract

Semiconductor-on-insulator (SOI) field effect transistors (FETs) including body regions having different thicknesses may be formed on an SOI substrate by selectively thinning a region of a top semiconductor layer while preventing thinning of an additional region of the top semiconductor layer. An oxidation process or an etch process may be used to thin the region of the top semiconductor layer, and a patterned oxidation barrier mask or an etch mask may be used to prevent oxidation or etching of the additional portion of the top semiconductor layer. Shallow trench isolation structures may be formed prior to, or after, the selective thinning processing steps. FETs having different depletion region configurations may be formed using the multiple thicknesses of the patterned portions of the top semiconductor layer. For example, partially depleted SOT FETs and fully depleted SOI FETs may be provided.