Characterization of SOI MOSFETs by gate capacitance measurements

A technique to extract the film thickness of silicon on insulator (SOI) MOSFETs from gate capacitance measurements on very large devices is validated through a detailed study including 2D numerical AC device simulations. A new extraction formula is developed. It enhances the precision of the method and extends its applicability to smaller channel lengths, and hence conventional test transistors. An original method unique to SOI MOSFETs is proposed to extract simultaneously the effective gate length and gate oxide and film thicknesses from a set of C-V measurements on transistors of varying lengths. The capabilities of the gate capacitance technique for extracting the physical strong inversion threshold voltage and the film doping level of SOI MOSFETs are demonstrated