Ultra-low leakage and high breakdown Schottky diodes fabricated on free-standing GaN substrate

Vertical Schottky diodes were fabricated on the bulk GaN substrate with decreasing impurity concentration from N-face to Ga-face. An array of circular Pt Schottky contacts and a full backside Ti/Al/Ni/Au ohmic contact were prepared on the Ga-face and the N-face of the n-GaN substrate, respectively. The Schottky diode exhibits a minimum specific on-state resistance of 1.3 m Omega cm(2) and a maximum breakdown voltage of 600 V, resulting in a figure-of-merit of 275 MW cm(-2). An ultra-low reverse leakage current density of 3.7 x 10(-4) A cm(-2) at reverse bias of 400 V was observed. Temperature-dependent I-V measurements were also carried out to study the forward and reverse transportation mechanisms.

Wang, Y., Alur, S., Sharma, Y., Tong, F., Thapa, R., Gartland, P., ... Evans, K. R. (2011). Ultra-low leakage and high breakdown Schottky diodes fabricated on free-standing GaN substrate. Semiconductor Science and Technology, 26(2), [022002]. DOI: 10.1088/0268-1242/26/2/022002