Recovery Performance of Ge-Doped Vertical GaN Schottky Barrier Diodes

Vertical GaN Schottky barrier diodes (SBDs) were fabricated on Ge-doped free-standing GaN substrates. The crystal quality of the SBDs was characterized by cathode luminescence measurement, and the dislocation density was determined to be ~ 1.3 × 10⁶ cm^- 2. With the electrical performance measurements conducted, the SBDs show a low turn-on voltage V_on (0.70~0.78 V) and high current I_on/I_off ratio (9.9 × 10⁷~1.3 × 10¹⁰). The reverse recovery characteristics were investigated. The reverse recovery time was obtained to be 15.8, 16.2, 18.1, 21.22, and 24.5 ns for the 100-, 200-, 300-, 400-, and 500-μm-diameter SBDs, respectively. Meanwhile, the reverse recovery time and reverse recovery charge both show a significant positive correlation with the electrode area.