A compact large-signal model for hydrogen-terminated (C-H) diamond metal-oxide field effect transistors (MOSFETs) is presented based on an improved quasi-physical zone division (QPZD) model. Unlike the conventional QPZD model for the AlGaN/GaN high-electron-mobility transistors (HEMTs), the linear-mode current-voltage (I-V) model of the diamond FET is analytically deduced with an improved velocity-electric field relation and temperature-dependent effective hole mobility μeff(T ). The I-V model can directly demonstrate the relation between the negative Vds and the negative Ids of the p-type diamond FETs, which cannot be achieved by the conventional QPZD model. Finally, the proposed model has been verified by the on-wafer measurements of an in-house 2 x 500 μm diamond FET. The good consistency shows that the presented compact large-signal model can accurately predict the DC I-V, multibias scattering-parameters (S-parameters), and large-signal performances. The results of this paper will be useful for the microwave diamond-based transistor and circuit designs.
