In this letter, we report on demonstrating high-performance field-plated lateral β-Ga ₂ O ₃ Schottky barrier diode (SBD) on a sapphire substrate with a reverse blocking voltage of more than 3 kV and a low dc specific ON-resistance (R _ON,sp ) of 24.3 mΩ·cm ² at an anode-cathode spacing (L _AC ) of 24 μm. To the best of our knowledge, this lateral breakdown voltage (BV) >3 kV with dc power figure-of-merit (FOM) >370 MW/cm ² is the highest BV achieved among all the β-Ga ₂ O ₃ SBDs. Meanwhile, lateral β-Ga ₂ O ₃ SBD with L _AC = 16 μm also demonstrates a high BV of 2.25 kV and low R _ON,sp = 10.2 mΩ·cm ² , yielding a record high dc power FOM of 500 MW/cm ² . Combining with 109 high-current ON/OFF ratio, 1.15-eV Schottky barrier height and 1.25 ideality factor, β-Ga ₂ O ₃ SBD with field-plate structure shows its great promise for power electronics applications.

Gallium nitride (GaN)-based vertical power Schottky barrier diode (SBD) has demonstrated outstanding features in high-frequency and high-power applications. This paper reviews recent progress on GaN-based vertical power SBDs, including the following sections. First, the benchmark for GaN vertical SBDs with different substrates (Si, sapphire, and GaN) are presented. Then, the latest progress in the edge terminal techniques are discussed. Finally, a typical fabrication flow of vertical GaN SBDs is also illustrated briefly.

In this work, we have demonstrated normally-off β-Ga2O3 metal-oxide-semiconductor field-effect transistor (MOSFET) with the ferroelectric charge storage gate stack structure. Saturation currents of 18.3 and 16.0 mA/mm were achieved in Depletion (D-) and Enhancement (E-) mode device, respectively, which shows negligible current reduction. Steep subthreshold swing (SS) of 72 mV/dec and breakdown voltage of 670 V were also obtained in the E-mode MOSFET. Furthermore, after gate stess test of 10 V for 105 s was performed. The threshold voltage (VTH) shift was 26.5 %. These electrical characteristics of the E-mode β-Ga2O3 MOSFET shows the great potential for future power switch application.

We report on the electrical and microstructural characterization of Au-free Ti/Al/Ti/TiN contacts for AlGaN/GaN heterostructures. Ultra-low Au-free ohmic contact has been obtained with contact resistance and specific contact resistivity as low as 0.21 Ω · mm and 1.16 x 10 ^-6 Ω · cm ² , respectively. The ohmic alloy temperature is reduced as low as 550 °C by pre-ohmic recess of the AlGaN barrier and optimization of the thickness of bottom Ti layer. We found that interfacial layer formation of AlN between the ohmic metal and AlGaN surface is crucial to realize a low contact resistance with reduced low annealing temperature by a combination of electrical I-V characterization and high-resolution transmission electron microscopy analysis. Furthermore, we suggest a hypothesis that the bottom Ti layer plays a catalytic role for the Al-N reaction with optimized thickness.

In this work, an enhancement-mode (E-mode) β-Ga₂O₃ metal-oxide-semiconductor field-effect transistor (MOSFET) has been achieved by incorporating a laminated-ferroelectric charge storage gate (L-FeG) structure [Al₂O₃/HfO₂/Al₂O₃/Hf_0.5Zr_0.5O₂ (HZO) of 10/5/2/16 nm]. The band diagram between L-FeG dielectrics (Al₂O₃, HfO₂, and HZO) and β-Ga₂O₃ was determined by x-ray photoelectron spectroscopy. After applying a gate pulse with an intensity of +18 V and width of 1 ms, the saturation current of the E-mode device was measured to be 23.2 mA/mm, which shows a negligible current reduction compared to that of 22.1 mA/mm in a depletion- (D-) mode device. In addition, the threshold voltage (V_TH) is only shifted by 2.76% and 2.18%, respectively, after applying the gate stress and gate-drain stress of 15 V for 10⁴ s. Meanwhile, a high breakdown voltage of 2142 V and specific on-resistance (R_ON,sp) of 23.84 mΩ·cm² were also achieved, which correspond to a state-of-art high power figure of merit of 192.5 MW/cm², showing the great potential of combing the ferroelectric gate stack and lateral Ga₂O₃ MOSFET as next generation power devices.