Influence of Bandstructure and Channel Structure on the Inversion Layer Capacitance of Silicon and GaAs MOSFETs

The influence of MOSFET channel material and channel structure on the inversion layer capacitance is examined. It is well known that the inversion layer capacitance depends strongly on the bandstructure of the channel, but we show that it also depends very strongly on the structure of the channel (e.g., bulk vs. ultrathin body, and the thickness of the body). These results provide some general insights into the channel material and structure tradeoffs that control the inversion layer capacitance-an increasingly important consideration as electrical oxide thicknesses continue to decrease and as new channel materials are considered.