Suppression of Current Leakage Along Mesa Surfaces in GaN-Based p-i-n Diodes

Trifluoromethane-containing plasma is used to passivate the mesa surfaces and suppresses the surface leakage current of GaN p-i-n rectifiers. Reduction of surface leakage enhances the reverse blocking voltage by 25% measured at J = 1 A/cm
²
. Differential forward resistances of control samples and plasma-treated ones are 0.65 and 0.49 mΩ-cm
²
, respectively, and an excellent Baliga's figure-of-merit of more than 800 MW/cm
²
, as compared with the conventional 545 MW/cm
²
, is achieved for GaN diodes fabricated on sapphire substrates.