High Uniformity Normally-OFF GaN MIS-HEMTs Fabricated on Ultra-Thin-Barrier AlGaN/GaN Heterostructure

Ultra-thin-barrier (UTB) AlGaN/GaN heterostructure is utilized for fabrication of normally-OFF GaN metal–insulator–semiconductor high-electron-mobility transistors (MIS-HEMTs). The sheet resistance of 2-D electron gas in the UTB Al
_0.22
Ga
_0.78
N(5-nm)/GaN heterostructure is effectively reduced by SiN
_x
passivation grown by low-pressure chemical vapor deposition, from 2570 to
$334~\Omega $
/□. The fabricated Al
₂
O
₃
/AlGaN/GaN MIS-HEMTs exhibit normally-OFF behavior with good
$V_{\mathrm {TH}}$
uniformity and low
$V_{\mathrm {TH}}$
-hysteresis. 20 mm-gate-width power devices featuring a low
$R_{\sc {\mathrm{ on}}}$
of
$0.75~\Omega $
(
$\text{I}_{\mathrm {D,MAX}} =6.5$
A) are also demonstrated on the platform.