[22p-E302-1~15] CS.9 Code-sharing Session of 13.7 & 15.6

▲ [22p-E302-12] Mg-implanted Vertical GaN Superjunction Barrier Schottky Rectifiers with Extremely Low On-Resistance, High Breakdown Voltage, Low Turn-On Voltage and Avalanche Capability

〇Tetsu Kachi¹, Maciej Matys¹, Tsutomu Uesugi¹, Kazuki Kitagawa², Jun Suda^1,2 (1.IMass, Nagoya Unuv., 2.Nagoya Univ.)

Keywords:GaN, Schottky diode, superjunction

We report the experimental demonstration of vertical gallium nitride (GaN) superjunction (SJ) devices. The SJ barrier Schottky (SJ-JBS) diode structure was formed by implantation of Mg ions into a 10 μm thick Si-doped GaN drift layer grown on a free-standing n-type GaN (0001) substrate under the <0001> channeling conditions with 180 keV energy. The depth of Mg was 4~5μm. The Mg ions were activated via the ultra-high-pressure annealing process. We fabricated the SJ-JBS diodes with a different n-GaN channel width: L_n=1 and 1.5 μm. The SJ-JBS diodes showed R_ON of 0.58-0.67 mOhm cm² and BV of 647-675 V. The leakage currents in SJ-JBS diodes were relatively low (10³-10⁴ lower than conventional GaN SBDs) and stable (low leakage slope). Moreover, the SJ-JBS diodes exhibited the low turn-on voltage (V_ON) of 0.7 V and the reverse avalanche capabilities against the rapid increase of the reverse current over 2.5 orders of magnitudes. This result shows that the vertical GaN SBDs based on the SJ structure can realize extremely low R_ON and low V_ON simultaneously keeping high BV, which makes them a strong candidate for ultra-low loss power switching applications.