1.2-kV Low-Barrier 4H-SiC JBS Diodes by Virtue of P-Implants Across Dead Field of Current Flow

A low value of Schottky barrier height (SBH) (
$\Phi _{B}{)}$
is highly desired to further reduce the power loss in 4H-SiC junction barrier Schottky (JBS) diodes; however, the reduced
$\Phi _{B}$
results in serious leakage current (
${I}_{R}{)}$
when blocking high voltages. In this work, a tunable low
$\Phi _{B}$
of 0.92–0.98 eV with an ideal factor
${n}$
= 1.02–1.03 was first realized through effectual rapid thermal annealing (RTA) methods and combined with a trench-assisted stage-style p-type implants taking advantage of dead region for current flow to resolve the
${I}_{\text {R}}$
issue. Numerical simulation demonstrated the superiority of this promising strategy in alleviating the Schottky interface electric field (
${E}_{\text {S}}{)}$
and suppressing
${I}_{R}$
without constraining the forward current flow. Based on this practical strategy, the fabricated device achieved one order of magnitude less
${I}_{R}$
at 25 °C and 220% enhancement of breakdown voltage (
${V}_{B}{)}$
at 175 °C in contrast to the conventional low-barrier one. In addition, benefiting from the low
$\Phi _{B}$
, the device achieved an ultralow turn-on voltage of 0.47 eV and a remarkable forward voltage drop (
${V}_{F}{)}$
of 1.36 V extracted at 20 A, indicating 14% lower conduction loss than the titanium-based JBS diodes with the same device configuration. This novel device structure incorporating low-barrier Schottky contact metal and trench-assisted stage-style p-implants (SPs) in the dead region of current flow suggests a promising way to develop more advanced 4H-SiC JBS diodes in the future.