LiF/Al₂O₃ as Dielectrics for MOSFET on Single Crystal Hydrogen-Terminated Diamond

Fabrication of single crystal hydrogen-terminated diamond MOSFET with dielectrics of LiF/Al
₂
O
₃
has been successfully carried out. After patterning source and drain electrodes, 60nm LiF/20nm Al
₂
O
₃
were deposited as dielectrics. The output and transfer characteristics were investigated, indicating the typical p-type channel MOSFET. The on/off ratio was ~10
⁹
, which was high enough for practical applications. The fixed and trapped charge in LiF/Al
₂
O
₃
were also examined. Based on the capacitance-voltage curves, the dielectric constant of LiF/Al
₂
O
₃
was calculated to be 36.1, which was ascribed to the LiF supercapacitor structure. To the best of our knowledge, this LiF supercapacitor structure was first used in hydrogen-terminated diamond MOSFET to improve the dielectric constant.