In this work, we show that the $\beta $ -Ga ₂ O ₃ Schottky Barrier Diode (SBD) can perform beyond the 1-D unipolar limit of the SiC and GaN by employing a deep trench with filled thick SiO ₂ layer structure to enhance the breakdown voltage (BV). By doing so, BV and specific on- resistance ( $\text{R}_{\text {on},\text {sp}}$ ) of 5–6 kV and 3.4 $\text{m}\boldsymbol {\Omega } \cdot \text {cm}^{{2}}$ are simultaneously derived on the SBDs with $\beta $ -Ga ₂ O ₃ epi-layer thickness of 10 $\boldsymbol {\mu } \text{m}$ and diode radius of 90 $\boldsymbol {\mu }\text{m}$ . Therefore, the Baliga’s power figure of merit (P-FOM = BV $^{{2}} /\text{R}_{\text {on,sp}}$ ) is yielded to be 7.4-10.6 GW $/$ cm ² . To the best of all authors’ knowledge, those P-FOMs are the highest values among all types of SBDs, which is a significant step towards the Ga ₂ O ₃ SBD performance improvement. Combined with negligible forward hysteresis and low reverse leakage current, vertical $\beta $ -Ga ₂ O ₃ SBDs with state-of-the-art BV and P-FOM show its great promise for next generation high voltage and high power applications.

In this work, we report on demonstrating the firstvertical ${\rm{\beta}-Ga_{2}O_{3}}$ junction barrier Schottky (JBS) diode with theimplementation of thermally oxidized p-type NiO to compensatethe dilemma of the forfeit of the p-type ${\rm{\beta}-Ga_{2}O_{3}}$ . With this widebandgap p-type NiOx, ${\rm{\beta}-Ga_{2}O_{3}}$ JBS diodes with an area of 100×100 ${\mu m^{2}}$ achieves a breakdown voltage (BV) and specific onresistance(Ron,sp) of 1715 V and 3.45 ${m\Omega\cdot cm^{2}}$ , respectively,yielding a Baliga'figure of merit (FOM) of ${BV^{2}/R_{on,sp}= 0.85 \rm{GW/cm^{2}}}$ , which is the highest direct-current (DC) FOM valueamong all ${\rm{\beta}-Ga_{2}O_{3}}$ diodes. Meanwhile, a large size JBS diodewith area of 1×1 ${mm^{2}}$ shows a forward current (IF) and BV of 5A/700 V, which is also the best IF and BV combinations (FOM =64 MW/ ${cm^{2}}$ ) among all published results about large area Ga2O3diodes. Dynamic switching characteristics reveal that the diodesuffers from negligible current collapse phenomenon even at a -600 V and 103 s stress, showing the great promise ofimplementing p-NiO in the future ${\rm{\beta}-Ga_{2}O_{3}}$ power electronicdevices.

In this work, we have demonstrated high-performance lateral β-Ga2O3 metal-oxide-semiconductor field-effect transistors (MOSFETs) with state-of-art power figure-of-merit (P-FOM) and breakdown voltage (BV) by adopting a T-shape gate field-plate and source connected field-plate structures. Depletion-mode (D-mode) β-Ga2O3 MOSFETs with gate-to-drain distance (LGD) of 4.8 μm/17.8 μm demonstrate a BV of 1.4 kV/2.9 kV and specific ON-resistance (Ron,sp) of 7.08 mΩ·cm2/46.2 mΩ·cm2, respectively, yielding a high P-FOM of 277 MW/cm2 and averaged electrical field of 2.9 MV/cm for the device with LGD = 4.8 μm. To the best of all the authors’ knowledge, this P-FOM of 277 MW/cm2 and BV = 2.9 kV are the highest values among all the lateral D-mode β-Ga2O3 MOSFETs. Combined with negligible gate pulsed and drain pulsed current collapse and drain current on/off ratio of 109, these β-Ga2O3 MOSFETs show a great potential for future power electronic applications.

We report on achieving high-performance β-Ga ₂ O ₃ power devices through the incorporation of the p-type NiO _x . β-Ga ₂ O ₃ p-n heterojunction (HJ) diodes, as well as the novel p-n HJ gate (G) field-effect-transistors (HJ-FETs), have all demonstrated state-of-the-art Baliga's power figure of merit (P-FOM). The HJ p-n diode is introduced to provide a large built-in potential and alleviate the peak electric field to enhance the BV. The non-field plated p-n HJ diode and HJ-FET acquire a breakdown voltage (BV)/specific on-resistance (R _on,sp ) of 1220 V/1.08 mΩ · cm ² and 1115 V/3.19 mΩ ·cm ² , respectively. Therefore, the P-FOM which is defined as the BV ² /R _on,sp is yielded to be 1.38 GW/cm ² and 0.39 GW/cm ² for p-n HJ diode and HJ-FET, respectively. Due to the hard realization of p-type Ga ₂ O ₃ , these findings show significant insights on the development of Ga ₂ O ₃ power devices and offer great promises of implementing p-NiO _x in boosting the Ga ₂ O ₃ power device performances.