2kV Low Leakage Vertical NiO/β-Ga2O3 Hetero-Junction Diode and its Thermal/Electrical Stability

This work demonstrates a vertical
$\text{NiO}/\beta-\text{Ga}_{2}\mathrm{O}_{3}$
Heterojunction Diode (HJD) with a deep trench termination. The 7μm deep trench is etched using a self-aligned technique to reduce electric field at the anode edge. Additionally, a combined
$\text{SiO}_{2}/\text{PI}/\text{Si}\mathrm{O}_{2}$
dielectric structure is used to fill the trench and an additional field plate is also used to reduce the electric field in
$\text{Ga}_{2}\mathrm{O}_{3}$
. TCAD simulations demonstrate a significant reduction in the electric field at the anode edge. The Mesa-HJD is fabricated along with the DT-HJD. The specific on resistance of them are both
$2.4\mathrm{m}\Omega\cdot \text{cm}^{2}$
. The fabricated DT-HJD shows a high breakdown voltage of
$> 2\text{kV}$
with a doping concentration of
$-3\times 10^{16}\text{cm}^{-3}$
. Consequently, a high-Power Figure of Merit (PFOM) of 1.
$75\text{GW}/\text{cm}^{2}$
is hence achieved. Moreover, a remarkably low leakage current of
$10^{-5}\mathrm{A}/\text{cm}^{2}$
at 1700 reverse bias is also achieved, which is among the lowest in multi-kilovolts
$\text{Ga}_{2}\mathrm{O}_{3}$
HJDs. The results demonstrate the promising potential of
$\text{Ga}_{2}\mathrm{O}_{3}$
HJD for power electronics applications.