Dry and wet etching for β-Ga₂O₃ Schottky barrier diodes with mesa termination

We investigated dry and wet etchings of β -Ga 2 O 3 and fabricated vertical Schottky barrier diodes (SBDs) with mesa termination using the optimal etching condition. Using an inductively-coupled plasma reactive-ion etching with a nickel-hard mask, a β -Ga 2 O 3 (010) mesa structure with a smooth sidewall is obtained at an etching rate of 77 nm min −1 in BCl 3 /Cl 2 mixture gas. By immersing β -Ga 2 O 3 (001) vertical SBDs with mesa termination in hot phosphoric-acid solution, the specific on resistance and ideality factor of the SBDs are reduced to 0.91 mΩcm 2 and 1.03, respectively. Current density at reverse bias is in good agreement with thermionic field emission model.