Hydrogen-terminated diamond field-effect transistor with a bilayer dielectric of HfSiON/Al2O3

Abstract

The fabrication of a single-crystal hydrogen-terminated diamond metal-oxide-semiconductor field-effect transistor (MOSFET) with HfSiON/Al2O3 bilayer dielectric has been carried out. HfSiON and Al2O3 layers were deposited by sputtering-deposition (SD) and atomic layer deposition (ALD) techniques. The maximum output current for SD-HfSiON/ALD-Al2O3 was 36 mA mm−1, and for ALD-Al2O3, it was 31 mA mm−1. We reported that the hysteresis shift voltage of the bilayer dielectric MOSFET was one fourth of the single dielectric layer MOSFET. The leakage current density of SD-HfSiON/ALD-Al2O3 was one order of magnitude lower than the single layer dielectric. We also determined the dielectric constants of HfSiON/Al2O3 and Al2O3 dielectrics based on capacitance–voltage characteristics. The values of VTH, on/off ratio, subthreshold swing, and low field mobility for the bilayer dielectric MOSFET were evaluated to be 4.5 V, 105, 296 mV/decade, and 154 cm2 V−1 s−1, respectively.