3326-V Modulation-Doped Diamond MOSFETs

This letter reports the fabrication and characterization of 3.3-kV modulation-doped diamond metal–oxide–semiconductor field-effect transistors (MOSFETs). The modulation doping was performed via NO
₂
delta doping in the Al
₂
O
₃
gate layer. The modulation-doped diamond MOSFET with a gate length of
$2.8~\mu \text{m}$
showed a maximum drain current density of 0.42 A/mm, with an estimated specific ON-resistance of
${13.48}~\text {m}\Omega \cdot \text {cm}^{{2}}$
. Therefore, the Baliga’s figure-of-merit (BFOM) was determined to be 820.6 MW/cm
²
. A subthreshold swing of 109.89 mV/dec, indicative of a high-quality Al
₂
O
₃
/diamond interface with an interfacial state density of
${1.49} \times {10}^{{12}}$
cm
⁻²
eV
⁻¹
, was obtained. The maximum effective mobility was estimated to be 496 cm
²
/Vs near the threshold, and a maximum output power density of 46.5 W/mm was projected.