Planar geometry, lateral Schottky rectifiers were fabricated on high resistivity AlxGa1-xN (x = 0-0.25) epitaxial layers grown on sapphire substrates. The reverse breakdown voltages of unpassivated devices increased with Al composition, varying from 2.3 kV for GaN to 4.3 kV for Al0.25Ga0.75N. The reverse current-voltage (I-V) characteristics showed classical Shockley-Read-Hall recombination as the dominant mechanism, with I∝ V0.5. The reverse current density in all diodes was in the range 5-10 × 10-6 A cm-2 at 2 kV. The use of p+ guard rings was effective in preventing premature edge breakdown and with optimum ring width increased VB from 2.3 to 3.1 kV in GaN diodes.
All Science Journal Classification (ASJC) codes
- Physics and Astronomy (miscellaneous)