A charge-based capacitance model of short-channel MOSFETs

A quasi-static two-dimensional intrinsic capacitance model for short-channel MOSFETs is discussed. It is derived based in a physically based charge-sharing scheme and implemented using a quasi-static solution of a MOS device simulator. Two-dimensional field-induced mobility degradation, velocity saturation, and short-channel effects are included in the model. The charge conservation rule holds, and channel charge partitioning is properly treated. The simulation results clearly show the importance of two-dimensional field-induced effects to short-channel MOS devices. Comparison of the simulated results with experimentally measured data shows that the model is far more reliable than the analytical one. The method can be used to link a device simulator and a circuit simulator for accurate timing calculation in both digital and analog MOS integrated circuits.<
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