Gate capacitance of back-gated nanowire field-effect transistors

Gate capacitances of back-gated nanowire field-effect transistors (NW-FETs) are calculated by means of finite element methods and the results are compared with analytical results of the “metallic cylinder on an infinite metal plate model.” Completely embedded and nonembedded NW-FETs are considered. It is shown that the use of the analytical expressions also for nonembedded NW-FETs gives carrier mobilities that are nearly two times too small. Furthermore, the electric field amplification of nonembedded NW-FETs and the influence of the cross section shape of the nanowires are discussed.