Ultra-wide bandgap semiconductor Ga₂O₃based electronic devices are expected to perform beyond wide bandgap counterparts GaN and SiC. However, the reported power figure-of-merit hardly can exceed, which is far below the projected Ga₂O₃material limit. Major obstacles are high breakdown voltage requires low doping material and PN junction termination, contradicting with low specific on-resistance and simultaneous achieving of n- and p-type doping, respectively. In this work, we demonstrate that Ga₂O₃heterojunction PN diodes can overcome above challenges. By implementing the holes injection in the Ga₂O₃, bipolar transport can induce conductivity modulation and low resistance in a low doping Ga₂O₃material. Therefore, breakdown voltage of 8.32 kV, specific on-resistance of 5.24 mΩ⋅cm², power figure-of-merit of 13.2 GW/cm², and turn-on voltage of 1.8 V are achieved. The power figure-of-merit value surpasses the 1-D unipolar limit of GaN and SiC. Those Ga₂O₃power diodes demonstrate their great potential for next-generation power electronics applications.

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.

Gallium oxide (Ga₂O₃) is an emerging ultra‐wide bandgap (UWBG) semiconductor material that has gained significant attention in the field of high voltage and high frequency power electronics. Its noteworthy attributes include a large bandgap (E_g) of 4.8 eV, high theoretical critical breakdown field strength (E_C) of 8 MV cm⁻¹, and saturation velocity (ν_s) of 2 × 10⁷ cm s⁻¹, as well as high Baliga figures of merit (BFOM) of 3000. In addition, Ga₂O₃ has the advantages of large‐size substrates that can be achieved by low‐cost melt‐grown techniques. This review provides a partial overview of pivotal milestones and recent advancements in the Ga₂O₃ material growth and device performance. It begins with a discussion of the fundamental material properties of Ga₂O₃, followed by a description of substrate growth and epitaxial techniques for Ga₂O₃. Subsequently, the contact technologies between Ga₂O₃ and other materials are fully elucidated. Moreover, this article also culminates with a detailed analysis of Ga₂O₃‐based high voltage and high frequency power devices. Some challenges and solutions, such as the lack of p‐type doping, low thermal conductivity, and low mobility are also presented and investigated in this review.