600-V Normally Off ${\rm SiN}_{x}$ /AlGaN/GaN MIS-HEMT With Large Gate Swing and Low Current Collapse

In this letter, 600-V normally-OFF
${\rm SiN}_{x}$
/AlGaN/GaN metal–insulator–semiconductor high-electron-mobility transistor (MIS-HEMT) is reported. Normally-OFF operation and low OFF-state gate leakage are obtained by using fluorine plasma ion implantation in conjunction with the adoption of a 17-nm
${\rm SiN}_{x}$
thin film grown by plasma-enhanced chemical vapor deposition as the gate insulator. The normally-OFF MIS-HEMT exhibits a threshold voltage of
${+}{\rm 3.6}~{\rm V}$
, a drive current of 430 mA/mm at a gate bias of 14 V, a specific ON-resistance of 2.1
${\rm m}\Omega\cdot{\rm cm}^{2}$
and an OFF-state breakdown voltage of 604 V at a drain leakage current of 1
$\mu{\rm A}/{\rm mm}$
with
$V_{\rm GS}=0~{\rm V}$
, and the substrate grounded. Effective current collapse suppression is obtained by AlN/
${\rm SiN}_{x}$
passivation as proved by high-speed pulsed
$I\hbox{--}V$
and low-speed high-voltage switching measurement results.