The development of monolithic integrated energy-efficient
complementary
circuits is crucial for the large-scale application of wide bandgap
semiconductor-based high-frequency and high-power field-effect transistors
(FETs). However, the inferior performance of p-channel FETs attributed
to low hole density and mobility presents a substantial challenge.
Diamond is a promising candidate due to its excellent comprehensive
electrical properties and high thermal conductivity. Here, we report
the fabrication of normally off diamond FETs based on a low work function
metal gate and (110) hydrogen-terminated diamond with high hole density.
The use of high-quality SiO2 layer ensures the complete
depletion of the channel by the gate and offers high gating efficiency.
Therefore, the developed devices demonstrate exceptional reproducibility
of normally off characteristics with centrally distributed threshold
voltages (−0.37 ± 0.3 V) and realize large current and
voltage handling capabilities and low static standby power consumption
in a synergic manner with record-high on/off ratio exceeding 1010, high current density (∼200 μA·μm–1), ultralow off-state current (∼fA·μm–1), and high breakdown voltage (−676 V). Additionally,
the thermal desorption of negatively charged acceptors has been proven
to significantly reduce carrier scattering. This work offers superior
performance p-channel FETs for implementing energy-efficient complementary
circuits, laying the groundwork for accelerated development in wide
bandgap semiconductor power electronics.