An analytical model for snapback in n-channel SOI MOSFET´s

An analytical snapback model for n-channel silicon-on-insulator (SOI) transistors with body either tied to the source or floating is been presented. The snapback is modeled as a nonlinear feedback system leading to negative transconductances from which the jump in current can occur at the point of instability. The crux of this model is based on the strong dependence of the transistor threshold voltage on the body potential when the body potential is above the transistor surface potential at strong inversion. No parasitic bipolar action is invoked to account for the snapback phenomena. The model correctly predicts the occurrence of hysteresis/latch phenomena and the conditions under which the current jump occurs despite some gross approximations in the electric field and the injection level. Results obtained from this model show good agreement with experimental data measured from SIMOX devices fabricated on 0.3-μm epi film