9-kV p-GaN Gate HEMT with Gate Termination Extension Demonstrated on Sapphire Substrate for Improved Breakdown Voltage

In this work, a <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$9-\text{kV}$</tex> E-mode p-GaN gate HEMT with gate termination extension (GTE-HEMT) is demonstrated on sapphire substrate. The GTE-HEMT with <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$L_{\text{GD}}=77 \mu \mathrm{m}$</tex> exhibits a low <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$R_{\text{ON}}$</tex> of <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$39.5 \Omega \cdot \text{mm}$</tex> and a specific <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$R_{\text{ON}}$</tex> of <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$34.76 \mathrm{m} \Omega \cdot \text{cm}^{2}$</tex>. Moreover, the gate termination extension effectively reduces the electric filed peak at the gate edge, leading to a high breakdown voltage of 9582 V and an excellent figure of merit (FOM) of <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$2.64 \text{GW} / \text{cm}^{2}$</tex>.