Charge-based modeling of capacitance in MOS transistors
Abstract
Conventional transistor models for the transient simulation of MOS circuits are formulated in terms of nonlinear capacitors. A charge-based model was developed to overcome errors and to account for the bulk charge. It is shown that the capacitances between any pair of terminals are nonreciprocal. Bulk-source, bulk-drain, and drain-source couplings are modeled, as are gate-to-bulk capacitances in saturation. The drain-source capacitances are negative. The capacitance characteristics of the model verified experimentally. The impact of the charge-based model on simulation of practical circuits was considered. Although the model is particularly useful in simulating silicon-on-insulator circuits, it gives improved simulation of bulk MOS technologies as well. Although the derivations are strictly valid only for long-channel devices operating at low speed, the model should prove useful for the simulation of practical circuits using state-of-the-art technology. Extensions of the model to short-channel devices and high-speed operation are discussed.
- Publication:
-
Ph.D. Thesis
- Pub Date:
- 1981
- Bibcode:
- 1981PhDT........36W
- Keywords:
-
- Capacitance;
- Capacitors;
- Computerized Simulation;
- Electric Charge;
- Metal Oxide Semiconductors;
- Transistor Circuits;
- Transistors;
- Computer Programs;
- Electric Current;
- Electric Potential;
- Gates (Circuits);
- Numerical Integration;
- Electronics and Electrical Engineering