2.4 kV Vertical GaN PN Diodes on Free Standing GaN Wafer Using CMOS-Compatible Contact Materials

Abstract

This paper reports vertical Gallium nitride (GaN) PN diodes on free-standing GaN wafer using a complementary metal-oxide-semiconductor compatible contact materials. Static and switching current-voltage measurements have been carried out to evaluate the fabricated vertical GaN PN diodes. The vertical GaN PN diode in this paper shows turn-on voltage Von of ~3.3-3.4 V, on/off current ratio of ~2.7 × 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">7</sup> , and ideal factor n of ~2.1. The reverse recovery time Trr is 21.2 ns and 23.2 ns, respectively, under a testing temperature of 300 K and 500 K. With an on-state resistance Ron of 3.9 mΩ·cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> and a breakdown voltage V <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">BR</sub> of 2.4 kV, this device achieves a power device figure-of-merit V <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">BR</sub> <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> /R <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">on</sub> of 1.5×10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">9</sup> V <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> Ω <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-1</sup> cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-2</sup> .