3659-V NO₂ p-Type Doped Diamond MOSFETs on Misoriented Heteroepitaxial Diamond Substrates

In this letter, we report an NO2 p-type doped and Al2O3 bilayer passivated diamond metal–oxide–semiconductor field-effect transistor (MOSFET) fabricated on a misoriented heteroepitaxial diamond substrate. The MOSFET demonstrated a high breakdown voltage of 3659 V, the highest reported among diamond MOSFETs. MOSFETs with a gate length of $2.5~\mu \text{m}$ exhibited a maximum drain current density of 372 mA/mm and maximum available power density (Baliga’s figure-of-merit) of 173 MW/cm2. In addition, the maximum mobility was estimated to be ${187}\,\text {cm}^{{2}}/\text {V}\cdot \text{s}$ , and the subthreshold swing was 189 mV/dec. This study explores the prospects of misoriented heteroepitaxial diamonds in power electronic device applications.