An analytic model for thin SOI transistors

A simple charge sheet model is shown to provide a surprisingly accurate approximation to the behavior of a long-channel FET fabricated in a silicon-on-insulator (SOI) structure with a very thin silicon film. Using this charge sheet model, an accurate calculation of the I-V characteristics of transistors fabricated in these thin films is derived. Included in the results is an expression for the threshold voltage which shows, among other things, that the threshold voltage of suitably designed transistors is only logarithmically dependent on the thickness of the silicon film.<
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