Low ON-Resistance GaN Schottky Barrier Diode With High $V_{\mathrm{ON}}$ Uniformity Using LPCVD Si3N4 Compatible Self-Terminated, Low Damage Anode Recess Technology

In this letter, we demonstrate a recessed-anode Schottky barrier diode (SBD) on a double AlGaN/GaN heterojunction structure. A self-terminated, oxidation/wet etching with low-pressure chemical vapor deposition (LPCVD) Si
₃
N
₄
mask is applied in the anode recess process. Unlike common plasma-based, dry etching techniques, the etched surface is not subjected to ion bombardment, and the etch depth is precisely controlled. As a result, a high effective channel mobility of 1079 cm
²
/
$\text {V}~\cdot ~\text {s}$
is maintained in the channel beneath the recess surface. The fabricated devices with a 15-
$\mu \text{m}$
anode-to-cathode distance (
${L} _{\mathrm {AC}}$
) are found to exhibit a uniform, low turn-ON voltage (
${V}_\mathrm {ON}$
) of 0.69 ± 0.03 V, and a low specific on-resistance (
${R} _{\mathrm{ON,SP}}$
) of 2.83
$\text{m}\Omega \cdot \text {cm}^{2}$
. The SBDs also show excellent off-state blocking characteristics due to the smooth recess interface together with the assistance of LPCVD grown Si
₃
N
₄
. A breakdown voltage of 1190 V is achieved for the SBDs with 15-
$\mu \text{m}~{L} _{\mathrm {AC}}$
at a leakage current criteria of
$1~\mu \text{A}$
/mm, and the Baliga’s figure-of-merit is 500 MW/cm
²
.