This letter reports high-voltage GaN field-effect transistors fabricated on Si substrates. A halide-based plasma treatment was performed to enable normally off operation. Atomic layer deposition of Al₂O₃ gate insulator was adopted to reduce the gate leakage current. Incorporation of multiple field plates, with one field plate connected to the gate electrode and two field plates connected to the source electrode successfully enabled a high breakdown voltage of 1200 V and low dynamic on-resistance at high-voltage operation.

This letter reports the first demonstration of gallium nitride (GaN) complementary metal-oxide-semi-conductor (CMOS) field-effect-transistor technology. Selective area epitaxy was employed to have both GaN N-channel MOSFET (NMOS) and P-channel MOSFET (PMOS) structures on the same wafer. An AlN/SiN dielectric stack grown by metal-organic chemical vapor deposition served as the gate oxide for both NMOS and PMOS, yielding enhancement-mode N- and P-channel with the electron mobility of 300 cm²/V-s and hole mobility of 20 cm²/V-s, respectively. Using the GaN CMOS technology, a functional inverter integrated circuit was fabricated and characterized.

This letter reports a GaN vertical trench metal-oxide-semiconductor field-effect transistor (MOSFET) with normally-off operation. Selective area regrowth of n±GaN source layer was performed to avoid plasma etch damage to the p-GaN body contact region. A metal-organic-chemicalvapor-deposition (MOCVD) grown AlN/SiN dielectric stack was employed as the gate “oxide”. This unique process yielded a 0.5-mm ² -active-area transistor with threshold voltage of 4.8 V, blocking voltage of 600 V at gate bias of 0 V, and on-resistance of 1.7 Ω at gate bias of 10 V.

Vertical GaN Schottky barrier diode (SBD) structures were grown by metal-organic chemical vapor deposition on free-standing GaN substrates. The carbon doping effect on SBD performance was studied by adjusting the growth conditions and spanning the carbon doping concentration between ≤3 × 10¹⁵ cm⁻³ and 3 × 10¹⁹ cm⁻³. Using the optimized growth conditions that resulted in the lowest carbon incorporation, a vertical GaN SBD with a 6-μm drift layer was fabricated. A low turn-on voltage of 0.77 V with a breakdown voltage over 800 V was obtained from the device.

Smooth N-polar $\text{GaN}/{\text{Al}}_x{\text{Ga}}_{1-x}\text{N}/\text{GaN}$ heterostructures with a different Al mole fraction were grown by metalorganic chemical vapor deposition on (0001) sapphire substrates with a misorientation angle of $4°$ toward the $a$ -sapphire plane. The sheet electron density of the two-dimensional electron gas (2DEG), which formed at the upper $\text{GaN}/{\text{Al}}_x{\text{Ga}}_{1-x}\text{N}$ interface increased with an increasing Al-mole fraction in the ${\text{Al}}_x{\text{Ga}}_{1-x}\text{N}$ layer and increasing silicon modulation doping, similar to the observations for Ga-polar heterostructures. The transport properties of the 2DEG, however, were anisotropic. The growth on vicinal substrates led to the formation of well ordered multiatomic steps during ${\text{Al}}_x{\text{Ga}}_{1-x}\text{N}$ growth and the sheet resistance of the 2DEG parallel to the steps was about $25\%$ lower than the resistance measured in the perpendicular direction. The fabricated devices exhibited a drain-source current, $I_{\text{DS}}$ , of 0.9 A/mm at a gate-source voltage $+1\text{V}$ . At a drain-source voltage of 10 V and $I_{\text{DS}}=300\text{mA}/\text{mm}$ , current-gain and maximum oscillation frequencies of 15 and 38 GHz, respectively, were measured.