Enhancing Key Performance of Vertical GaN Schottky Barrier Diodes Through AlOxInsertion and Dual Ion Co-Implantation

The main challenges in current vertical GaN diodes involve electric field crowding effects and ohmic contacts on the nitrogen face (N-Face). Extensive prior research has been conducted in these areas. In this study, we introduced a novel dual-ion (carbon and helium) co-implantation edge termination (ET), aiming to enhance the breakdown voltage
$(V_{\text{BR}})$
capability of vertical GaN Schottky barrier diodes (SBDs). Furthermore, atomic layer deposition (ALD) was applied on the N-face to deposit a 1.2 nm aluminum oxide
$(\text{AlO}_{x})$
layer, effectively reducing the contact resistance of the ohmic contacts
$(\rho_{\mathrm{c}})$
. The fabricated devices exhibit a low turn-on voltage
$V_{\text{on}}$
of 0.56 V and a high
$I_{\text{on}}/I_{\text{off}}$
of
$\sim 10^{9}$
. The introduction of
$\text{AlO}_{x}$
mitigates the Fermi-level pinning effect (FLP), reducing the device resistance
$R_{\text{on},\text{sp}}$
from 3.01
$\mathrm{m}\Omega\cdot \text{cm}^{2}$
to 1.34
$\mathrm{m}\Omega\cdot \text{cm}^{2}$
. Moreover, the dual-ion co-implantation ET enables the devices to achieve a maximum
$V$
BR
of 1410 V, resulting in a high figure of merit (FOM) of 1.48 GW/cm
²
.