Negative conductance model for short-channel SOI MOSFET

A short-channel SOI (silicon on insulator) n-channel MOSFET when source/drain junctions bottom out to the buried oxide may display a negative conductance in the output characteristics when the body tie is connected to the source. This phenomenon has been recently attributed to a temperature effect. However, the temperature effect is too small to account for the observation. Based on the theory of charge particle interaction in an electric field (between the channel electron flow and hole flow generated by impact ionization), a physical model is derived to account for the observation of the negative conductance. The model is implemented in a modified SPICE program to facilitate the verification. The model fits to a short-channel SOI n-channel MOSFET made on a thin low-defect SIMOX material at V/sub GS/=5.0 V.<
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