1.5-kV and 2.2-m \(\Omega \) -cm \(^{2}\) Vertical GaN Transistors on Bulk-GaN Substrates

In this letter, vertical GaN transistors fabricated on bulk GaN substrates are discussed. A threshold voltage of 0.5 V and saturation current >2.3 A are demonstrated. The measured devices show breakdown voltages of 1.5 kV and specific ON-resistance of 2.2 mΩ-cm
²
, which translates to a figure-of-merit of V
_BR
²
/R
_ON
~1 × 10
⁹
V
²
Ω
^-1
· cm
^-2
.