Researchers from the University of Hong Kong (HKU) and the Center for Advanced Semiconductors and Integrated Circuits (CASIC), led by Professor Yuhao Zhang, Dr. Hehe Gong and graduate student Xin Yang, together with colleagues from Virginia Polytechnic Institute and Nanjing University, have developed a power module based on gallium oxide (Ga2O3). The results were published in the journal Nature Communications.
Gallium oxide belongs to the class of ultra-wide bandgap (UWBG) semiconductors - materials that withstand very strong electric fields without breaking down. This makes them promising for high-power electronics. However, gallium oxide has a weak point: it dissipates heat poorly. In addition, combining several such devices into a single module for operation at high voltage and current is technically difficult. Therefore, earlier real Ga2O3 devices showed relatively low power.
To get around the limitations, the team designed the semiconductor and the package as a single system. In particular, the researchers proposed a junction-side cooling architecture: the region where heat is generated was placed closer to the heat removal path. In addition, they introduced an insulating layer with a high dielectric constant - the ability of a material to accumulate electric charge under the action of a field - which helps redistribute the electric field around the device. As a result, heat is removed more efficiently, and the module withstands higher voltage.
In pulsed mode (short on-times), a single packaged Ga2O3 device conducted a current of 234 amperes at a voltage of 1000 volts and remained operational at a junction temperature above 250 degrees Celsius. Then six such devices were combined into a module that switched repeatedly at 1000 V and 1000 A at a frequency of 1 kHz. The peak power was one megawatt.
"This is the first time an ultra-wide bandgap multi-die module has reached the megawatt power level," Hehe Gong is quoted as saying in a press release. "More importantly, the result provides a scalable approach for turning the exceptional properties of such materials into practical high-power systems."
The authors note that the technology is especially promising for pulsed applications where enormous energy must be delivered in microseconds. Possible areas include protecting future power grids from high voltages, medical equipment, particle accelerators and fusion facilities. The module's fast switching may also enable more compact and efficient power converters.
The work continues the team's previous research on co-designing devices and packages; one of these was recognized as a technical highlight at the IEEE IEDM 2025 conference. The significance of the field was also discussed in a News & Views article in Nature Electronics in 2025 under the headline "Powering the ultrawide-bandgap era".