General large-signal charge-control equations for the MOSFET drainand source current under nonquasistatic conditions

摘要

General large-signal charge-control equations for the drain andnsource terminal currents of the long-channel MOSFET on a previouslynproposed recursion relation are presented. These equations arenphysically derived following Van Nielen's iterative procedure to revealnthe relaxation mechanism in the MOSFET channel under nonquasistaticnconditions. The relation between the channel charge partitioning modelnand the general theoretical development is discussed. This makes itnpossible to put various solution techniques reported for the MOSFETnnonquasistatic problem into perspective. Within the theoreticalnframework of this work, it is observed that, in general, the drain andnsource currents share a common relaxation time. The generalncharge-control equations presented in the paper differ from the simplenfirst-order nonquasistatic current equations, in that they incorporatencorrection terms to account for the otherwise neglected high-ordernnonquasistatic effects. Quasistatic formulation of these correctionnterms is used to illustrate their effects on transient response. It isnshown that consistency in the introduction of such correction terms tonspecific models is crucial to the continuity in current valuesnthroughout the transient