The I-V characteristics of SOI MOSFET are studied and an analytic model for SOI MOS devices is established.The model

which is valid for any SOI film thickness and each kind of front/back-gate bias conditions

has such advantages as analytic expression

clear physical meaning

simple and quick calculation

and easy extraction of used parameters.For each SOI film thickness or back gate bias

the suitable expression will be adopted automatically by the computer.The simulation results are well consistent with the experimental data.