875-MW/cm² Low-Resistance NO₂ p-Type Doped Chemical Mechanical Planarized Diamond MOSFETs

In this study, an Al
₂
O
₃
passivated, NO
₂
p-type doped diamond metal–oxide–semiconductor field-effect transistor (MOSFET) was fabricated on a chemical mechanical planarized high-quality heteroepitaxial diamond (Kenzan diamond
^®
) substrate. This MOSFET exhibited a low specific ON-resistance of 7.54
$\text{m}\Omega \cdot $
cm
²
and a high OFF-state breakdown voltage of −2568 V. The chemical mechanical planarization (CMP) was performed for 200 h on the diamond surface which effectively removed the subsurface damages resulting in a low resistive diamond surface. Thus, the MOSFET showed a high drain current density of −0.68 A/mm and a maximum available power density (Baliga’s figure-of-merit) of 874.6 MW/cm
²
—the highest reported value for diamond devices.