Suppressed charge trapping characteristics of (NH₄)₂S_x passivated GaN MOS device with atomic layer deposited HfAlO_x gate dielectric

다국어 초록 (Multilingual Abstract)

<P><B>Abstract</B></P> <P>The charge trapping behaviors of ammonium poly-sulfide, (NH<SUB>4</SUB>)<SUB>2</SUB>S<SUB>x</SUB>, passivated GaN MOS device with atomic layer deposited HfAlO<SUB>x</SUB> gate dielectric and DC-sputtered TiN gate electrode are investigated and compared with those of GaN MOS device with hydrochloric acid, HCl, passivation. Compared to non-S passivated device, higher peak capacitance (>20% @1MHz), reduced frequency dispersion (~30% ↓), lower hysteresis (~34% ↓), higher breakdown (1.3×), lower stress induced flat-band voltage (V<SUB>FB</SUB>) shift (~30% ↓), and lower interface state density (D<SUB>it</SUB>), stronger immunity D<SUB>it</SUB> generation (ΔD<SUB>it</SUB>) against gate bias voltage are attained with S-passivated device. Further improved characteristics are observed with post deposition annealing at 400°C for 10min. These behaviors are mainly attributed to higher bond strength energy of SO and SN than those of ClO and ClN bonds.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Sulfur passivation induces higher C<SUB>ox</SUB>, reduced frequency dispersion, lower hysteresis, higher V<SUB>BD</SUB>, and lower D<SUB>it</SUB>. </LI> <LI> Stress induced ΔV<SUB>FB</SUB> and ΔD<SUB>it</SUB> are significantly suppressed with sulfur-passivation. </LI> <LI> Further improvement is still observed after post annealing at 400 <SUP>o</SUP>C. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>