A Physical Model of Floating Body Thin Film Silicon-On-Insulator nMOSFET with Parasitic Bipolar Transistor

Abstract

An analytical model for SOI nMOSFET with a floating body is developed to describe the I(ds)-V(ds) characteristics. Considering all current components in MOSFET as well as parasitic BJT, this study evaluates body potential, investigates the correlations among many device parameters, and characterizes the various phenomena in floating body: threshold voltage reduction, kink effect, output conductance increment, and breakdown voltage reduction. This study also provides a good physical insight on the role of the parasitic current components in the overall device operation. Our model explains the dependence of the channel length on the I(ds)-V(ds) characteristics with parasitic BJT current gain. Results obtained from this model are in good agreement with the experimental I(ds)-V(ds) curves for various bias and geometry conditions.