Vertical GaN Schottky barrier diodes with ohmic contact on N-polar by the atomic layer deposition of aluminum oxide interfacial layer

In this paper, high-performance vertical GaN on GaN Schottky Barrier Diodes (SBDs) on 2-inch free-standing (FS)-GaN is presented with the specific on-state resistance (R_on) of 1.34 mΩ·cm², breakdown voltage (V_br) of 1150 V and figure of merit (FOM) of 0.98 GW/cm². He-implanted edge termination (ET) structure is introduced to alleviate the peak electric field concentration effect at the anode edge of GaN SBDs. Furthermore, A new ohmic contact structure is explored by atomic layer deposition (ALD)-grown AlO_x interfacial layer. Based on the self-cleaning effect of ALD and Ultra-thin AlO_x interfacial layer, the Fermi-level Pinning (FLP) effect is alleviated effectively, the specific contact resistivity (ρ_c) on N-polar GaN was reduced from 1.63 × 10⁻³ to 7.14 × 10⁻⁵ Ω·cm².The temperature variation test demonstrate the devices has potential of temperature sensors under high voltage and high temperature.