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 x /Al 2 O 3 bilayer dielectrics is fabricated and characterized. The HfAlO x /Al 2 O 3 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 TH ) is 8.3 V. The maximum drain source current density (I DSmax ), transconductance (G m ), capacitance (C OX ) and carrier density (ρ) are -6.3 mA/mm, 0.73 mS/mm, 0.22 μF/cm 2 and 1.53 × 10 13 cm -2 , respectively.