HfAlO x /Al 2 O 3 Bilayer Dielectrics for a Field Effect Transistor on a Hydrogen-Terminated Diamond

In this work, a hydrogen-terminated (H-terminated) diamond field effect transistor (FET) with HfAlO /Al O bilayer dielectrics is fabricated and characterized. The HfAlO /Al O bilayer dielectrics are deposited by the atomic layer deposition (ALD) technique, which can protect the H-terminated diamond two-dimensional hole gas (2DHG) channel. The device demonstrates normally-on characteristics, whose threshold voltage (V ) is 8.3 V. The maximum drain source current density (I ), transconductance (G ), capacitance (C ) and carrier density (ρ) are -6.3 mA/mm, 0.73 mS/mm, 0.22 μF/cm and 1.53 × 10 cm , respectively.