High-current metal oxide semiconductor field-effect transistors on h-terminated diamond surfaces and their high-frequency operation

Metal semiconductor field-effect transistors (MESFETs) or metal oxide semiconductor FETs (MOSFETs) can be fabricated on hydrogen-terminated diamond without losing the surface hydrogen-carbon bonds and the surface adsorbates responsible for the surface carrier generation. Those FETs show their best performance in diamond transistors. The maximum drain current density is above 1A/mm and the highest transconductance is 400mS/mm. These values are comparable to those of modern FETs made of Si or III-V semiconductors. Regarding RF performance, the highest cutoff frequency reaches nearly 50 GHz. The power handling capability exceeds those of Si and GaAs at 1 GHz. The function of surface adsorbates and their stabilization are crucial for the application of diamond FETs.