In this letter, the ultrafast reverse recovery β -Ga ₂ O ₃ Schottky barrier diode (SBD) with improved breakdown voltage is proposed and investigated experimentally. It features the compound termination, consisting of air space field plate and thermal oxidation terminal. The compound termination not only reduces high-density interface states at the dielectric/Ga ₂ O ₃ interface and the electron concentration in the oxidation terminal, but also modulates the electric-field distribution and suppresses the peak electric-field at the bottom of anode. Therefore, the reverse leakage current is suppressed as well as the reverse recovery and breakdown characteristics are improved effectively. The Ga ₂ O ₃ SBDs with the diameter of 1000 μm obtain ultrashort reverse recovery time of 7.5 ns and ultralow reverse recovery charge of 1.0 nC at di / dt = 50 A/μs with its breakdown voltage up to 400 V, maintaining good rectification characteristics. The temperature-dependences of both forward conduction and reverse recovery characteristics are discussed in temperature range from 300 to 500 K. The results prove that the superior electronics performance of the β -Ga ₂ O ₃ SBDs with good electronics thermal tolerance can overcome the low thermal conductivity of β -Ga ₂ O ₃ to a certain extent. The fabricated β -Ga ₂ O ₃ SBDs have great potential for high power and high-frequency applications.

In this study, we proposed and experimentally demonstrated a high breakdown voltage (BV) and low dynamic ON-resistance (RON, D) AlGaN/GaN high electron mobility transistor (HEMT) by implanting fluorine ions in the thick SiNx passivation layer between the gate and drain electrodes. Instead of the fluorine ion implantation in the thin AlGaN barrier layer, the peak position and vacancy distributions are far from the two-dimensional electron gas (2DEG) channel in the case of fluorine ion implantation in the thick passivation layer, which effectively suppresses the direct current (DC) static and pulsed dynamic characteristic degradation. The fluorine ions in the passivation layer also extend the depletion region and increase the average electric field (E-field) strength between the gate and drain, leading to an enhanced BV. The BV of the proposed HEMT increases to 803 V from 680 V of the conventional AlGaN/GaN HEMT (Conv. HEMT) with the same dimensional parameters. The measured RON, D of the proposed HEMT is only increased by 23% at a high drain quiescent bias of 100 V, while the RON, D of the HEMT with fluorine ion implantation in the thin AlGaN barrier layer is increased by 98%.

In this work, we propose combining a low work function anode metal and junction barrier Schottky structure to simultaneously achieve low turn-on voltage (Von) and high breakdown voltage (BV), which alleviates the dilemma that high BV requires high Schottky barrier height (SBH) and high Von. Molybdenum (Mo) is used to serve as the anode metal to reduce the SBH and facilitate fast turn-on to achieve a low Von. To resolve the low SBH related low BV issue, a p-NiO/n-Ga2O3-based heterojunction structure is used to enhance β-Ga2O3 sidewall depletion during the reverse state to improve the BV. With such a design, a low Von = 0.64 V(@1A/cm2) and a high BV = 2.34 kV as well as a specific on-resistance (Ron,sp) of 5.3 mΩ cm2 are demonstrated on a 10 μm-drift layer with a doping concentration of 1.5 × 1016 cm−3. β-Ga2O3 JBS diodes with low Von = 0.64 V and a power figure of merit of 1.03 GW/cm2 show great potential for future high-voltage and high-efficiency power electronics.

A novel ultra-fast snapback-free CTG RC-IGBT is proposed and investigated by simulation. It features a controllable trench gate (CTG) in the collector side and a bias voltage (V RC) is applied between the CTG and collector electrode. In the forward conduction state with V RC < 0, a high density hole inversion layer is formed around the CTG. The CTG acts as not only a folded controllable hole injector to enhances the hole injection efficiency, but also an electron barrier to increase the distributed resistance. The CTG RC-IGBT achieves a low on-state voltage drop (V on) and snapback-free with a small cell pitch. In the blocking state with V RC > 0, an electron accumulation layer is formed around the CTG. The electron layer together with the CTG acts as an equivalent N-buffer layer to stop the electric field and support high breakdown voltage. During turn-off, the CTG RC-IGBT behaves like a unipolar device without long tail current because the hole injection is deactivated by properly switching the V RC. Compared with conventional RC-IGBT, the proposed device decreases the V on and turn-off energy loss (E off) by 34% and 74% respectively under the load current of 100A/cm2 and bus voltage of 600V.

In this work, a reverse conduction beta-phase gallium oxide ( $\beta $ -Ga ₂ O ₃ vertical FinFET with an integrated Fin diode (FD) is proposed to improve reverse conduction characteristics with little effect on the threshold voltage ( ${V}_{\text {th}}$ ) and breakdown voltage (BV). Its electrical characteristics are studied and analyzed by Sentaurus technology computer aided design (TCAD) simulation. The integrated FD achieves metal–insulator–semiconductor (MIS)-like conduction/blocking characteristics owing to the Fin channel combined with an Ohmic contact anode. In the reverse conduction state, the FD first realizes a very low reverse turn-on voltage ( ${V}_{\text {on}}$ ), and then forms the electron accumulation layers along the Fin sidewalls to improve reverse current capability; in the forward conduction and blocking states, the Fin channel of FD is pinched off by the MIS structures from the two sidewalls due to the work function difference between the source metal and $\beta $ -Ga ₂ O ₃ , without obvious influence on the forward conduction and blocking characteristics. Compared with the conventional FinFETs (C-FinFETs), the reverse conduction $\beta $ -Ga ₂ O ₃ vertical FinFET (RC-FinFET) reduces the ${V}_{\text {on}}$ by 71% with almost the same ${V}_{\text {th}}$ and BV values. The proposed $\beta $ -Ga ₂ O ₃ RC-FinFET achieves a low ${V}_{\text {on}}$ of 0.45 V, high ${V} _{\text {th}}$ of 1.6 V, BV of 2545 V, and Baliga’s figure of merit (BFOM) up to 1.41 GW/cm ² . In addition, compared to a field effect transistor (FET) externally connecting a freewheeling diode, the RC-FinFET reduces the parasitic inductance and the total chip area, enhancing its application potential for high-power and low-loss power conversion systems.