145-MW/cm2 Heteroepitaxial Diamond MOSFETs with NO2 p-type Doping and an Al2O3 Passivation Layer

In this study, we investigated diamond metal oxide semiconductor field effect transistors (MOSFETs) with NO2 p-type doping and Al2O3 passivation layer fabricated on a high-quality heteroepitaxial single crystal (001) diamond substrate called Kenzan diamond®. MOSFETs with a gate length of 1.4 $\mu \text{m}$ and nearly zero source-gate spacing exhibited a high drain current density of −776 mA/mm with a negligible gate leakage current ( $ /mm). MOSFETs with a gate-to-drain length of 4.8 $\mu \text{m}$ delivered a high off-state breakdown voltage (−618 V) at an average breakdown field of 1.2 MV/cm and a specific on-resistance of 2.63 $\text{m}\Omega \cdot $ cm2. Baliga’s Figure-Of-Merits was calculated as 145 MW/cm2 and the anticipated maximum power density was 12 W/mm. The diamond MOSFET was improved with high crystal quality.