BSIM3v3.2.2 MOSFET Model - The University of Texas at Dallas
BSIM3v3.2.2 MOSFET Model - The University of Texas at Dallas
BSIM3v3.2.2 MOSFET Model - The University of Texas at Dallas
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CHAPTER 5: Non-Quasi St<strong>at</strong>ic <strong>Model</strong>5.1 Background Inform<strong>at</strong>ionAs <strong>MOSFET</strong>’s become more performance-driven, the need for accur<strong>at</strong>e prediction<strong>of</strong> circuit performance near cut-<strong>of</strong>f frequency or under very rapid transientoper<strong>at</strong>ion becomes more essential. However, most SPICE <strong>MOSFET</strong> models arebased on Quasi-St<strong>at</strong>ic (QS) assumptions. In other words, the finite charging timefor the inversion layer is ignored. When these models are used with 40/60 chargepartitioning, unrealistically drain current spikes frequently occur [33]. In addition,the inability <strong>of</strong> these models to accur<strong>at</strong>ely simul<strong>at</strong>e channel charge re-distributioncauses problems in fast switched-capacitor type circuits. Many Non-Quasi-St<strong>at</strong>ic(NQS) models have been published, but these models (1) assume, unrealistically,no velocity s<strong>at</strong>ur<strong>at</strong>ion and (2) are complex in their formul<strong>at</strong>ions with considerablesimul<strong>at</strong>ion time.5.2 <strong>The</strong> NQS <strong>Model</strong><strong>The</strong> NQS model has been re-implemented in BSIM3v3.2 to improve thesimul<strong>at</strong>ion performance and accuracy. This model is based on the channel chargerelax<strong>at</strong>ion time approach. A new charge partitioning scheme is used, which isphysically consistent with quasi-st<strong>at</strong>ic CV model.<strong>BSIM3v3.2.2</strong> Manual Copyright © 1999 UC Berkeley 5-1
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