1.5-kV (reverse breakdown) AlGaN/GaN lateral Schottky barrier diode on a Si substrate by surface-O2 treatment

A high-voltage GaN Schottky barrier diode (SBD) on a Si substrate was fabricated by surface-O
₂
treatment. The surface of the active area was annealed in O
₂
ambient at 800
^o
C after Ohmic-contact formation. The isolation-leakage current, which flowing from a mesa to another one, was considerably suppressed from 2.4×10
^-3
to 2.7×10
^-10
A/mm at 100 V by O
₂
treatment. The device leakage current was also decreased from 2.4×10
^-2
to 1.7×10
^-4
mA/mm at -100 V. The O
₂
treatment seems to form group-III oxides on the surface which may passivate surface states. The breakdown voltage of O
₂
-treated GaN SBDs with a drift length of 5, 10, and 20 μm were 700, 1400, and 1530 V, respectively.