Enhancement-Mode InAlN/GaN Power MOSHEMT on Silicon With Schottky Tri-Drain Extension

This study demonstrates an enhancement-mode (E-mode) InAlN/GaN MOSHEMT on a silicon substrate with a Schottky tri-drain extension (STDE) to yield a large breakdown voltage (V
_BD
) while maintaining a low on-resistance (R
_on
). The E-mode operation is realized by a recessed tri-gate nanowire structure. The STDE functions as a drain-connected field plate (FP) to effectively distribute the electric field (E-field) around the drain contact edge, improving the V
_BD
. Moreover, through the metal of the STDE directly contacting the 2-D electron gas (2-DEG) from the sidewalls, a low specific R
_on
(R
_on,
sp
) is achieved. The proposed device with a gate-to-drain length (L
_GD
) of 5 μm exhibits a threshold voltage (V
_TH
) of +0.9 V, large maximum drain current (I
_D,
max
) of 815 ± 27 mA/mm, high I
_on
/I
_off
ratio of 1010, steep subthreshold swing (SS) of 67 mV/decade, superior V
_BD
of 830 V, and low R
_on,
sp
of 0.74 ± 0.04 mΩ·cm
²
. With L
_GD
of 10 μm, a V
_BD
of 1190 V is achieved, corresponding to a R
_on,
sp
of 1.39 ± 0.07 mΩ·cm
²
. These results reveal great potential for future E-mode power device applications.