An avalanche-and-surge robust ultrawide-bandgap heterojunction for power electronics

Abstract

Avalanche and surge robustness involve fundamental carrier dynamics under high electric field and current density. They are also prerequisites of any power device to survive common overvoltage and overcurrent stresses in power electronics applications such as electric vehicles, electricity grids, and renewable energy processing. Despite tremendous efforts to develop the next-generation power devices using emerging ultra-wide bandgap semiconductors, the lack of effective bipolar doping has been a daunting obstacle for achieving the necessary robustness in these devices. Here we report avalanche and surge robustness in a heterojunction formed between the ultra-wide bandgap n-type gallium oxide and the wide-bandgap p-type nickel oxide. Under 1500 V reverse bias, impact ionization initiates in gallium oxide, and the staggered band alignment favors efficient hole removal, enabling a high avalanche current over 50 A. Under forward bias, bipolar conductivity modulation enables the junction to survive over 50 A surge current. Moreover, the asymmetric carrier lifetime makes the high-level carrier injection dominant in nickel oxide, enabling a fast reverse recovery within 15 ns. This heterojunction breaks the fundamental trade-off between robustness and switching speed in conventional homojunctions and removes a key hurdle to advance ultra-wide bandgap semiconductor devices for power industrial applications.

A landscape of β-Ga2O3 Schottky power diodes

“…First, the power-law temperature dependence of the R ON,sp in β-Ga 2 O 3 devices shows a temperature coefficient 2 to 4 times smaller than the corresponding values of SiC SBDs. This is possibly due to a weak temperature dependence of electron mobility in β-Ga 2 O 3 and an increase in donor ionization at high temperatures [94] , both reducing the risk of thermal runaway. Second, the doubleside and flip-chip packaging strategies allow heat extraction directly from the Schottky junction rather than through the thermally resistive β-Ga 2 O 3 substrate.…”

Toward Smart, Flexible, and Omnidirectional Self-Powered Photodetection by an All-Solution-Processed In2O3/Pbl2 Heterojunction

“…Zan et al quenched the PPC phenomenon by constructing P3HT/InGaZnO heterojunction, where the electrons accumulated at the interface and recombined with the holes inside the P3HT film rapidly after removing the light illumination . Additionally, benefiting from the large barrier height and built-in electric field, the construction of heterojunction can also effectively suppress the dark current, promising the I light / I dark ratios and the detectivitly ( D *) of photodetectors. − …”

2 in. Bulk β-Ga2O3 Single Crystals Grown by EFG Method with High Wafer-Scale Quality

“…As a new emerging ultrawide band gap semiconductor, gallium oxide (Ga 2 O 3 ) possesses a large band gap of 4.9 eV, a high breakdown field of 8 MV/cm, and a desirable Baliga’s figure of merit of 3214. Additionally, it exhibits strong bonding structures with Ga- and O-displacement energies of 25 and 28 eV, respectively. , These excellent material characteristics enable Ga 2 O 3 to find extensive applications in electronic and optoelectronic devices, even comparable with GaN and SiC. , In recent years, numerous successful device demonstrations of Ga 2 O 3 , such as deep-ultraviolet photodetectors, − resistive random access memories, , gas sensors, light-emitting diodes, photocatalysts, Schottky diodes, heterojunction diodes, and metal oxide semiconductor field effect transistors for power devices, − have been explored and investigated experimentally. In all examples, the performance of these devices is highly dependent on the material merit of Ga 2 O 3 .…”