Diamond field effect transistors using bilayer dielectrics Yb2TiO5/Al2O3 on hydrogen-terminated diamond

Abstract

In this study, we fabricated and studied metal-oxide-semiconductor field effect transistors (MOSFETs) using bilayer Yb2TiO5/Al2O3 dielectrics on single crystal hydrogen-terminated diamond (H-diamond). Dielectric materials Yb2TiO5 and Al2O3 were deposited on H-diamond surface using radio frequency sputtering and atomic layer deposition, respectively. We point out that leakage current and hysteresis shift voltage of bilayer dielectric were three order of magnitude lower and one-third that of single layer Al2O3 dielectric, respectively. Based on capacitance-voltage characteristics dielectric constant, trapped charges and carrier hole density were evaluated for SD-Yb2TiO5/ALD-Al2O3 and ALD-Al2O3 MOSFET's. The effective mobility for Yb2TiO5/Al2O3 sample evaluated by using the relation between on-state resistance and 1/|VGS-VTH|was 102.4 cm2.V−1.s−1.