Six-die gallium oxide module switches 1000 A at 1000 V in pulses, University of Hong Kong team reports

A team led by the University of Hong Kong has built a packaged power module of six gallium oxide switches that repeatedly switched 1000 V and 1000 A in pulses, according to a paper in Nature Communications. The authors describe it as the first packaged multi-die ultra-wide bandgap power module. They report that it raises the power capacity of ultra-wide bandgap electronics by over two orders of magnitude nature.comNature Communicationsnature.comOpen source ↗.

The 1000 V and 1000 A combination corresponds to about a megawatt of peak power during the pulses. This is a short-burst rating: continuous operation at that level would pose a different cooling problem. Earlier discrete ultra-wide bandgap devices had reached switching capacities up to the kilowatt level.

Package and heat management

Gallium oxide withstands strong electric fields, which suits high-voltage equipment, but heat removal from the material has been difficult. Heat trapped near the active region of a switch limits the current the device can carry safely. The team redesigned the package in a flip-chip configuration to give heat a shorter path out.

They also used a high-permittivity interface layer to spread the electric field and reduce stress at vulnerable points. According to the authors, this device-package electrothermal co-optimization maximizes transient thermal performance. It lets the module use the high volumetric heat capacity of gallium oxide, an advantage that earlier device work largely left untapped, together with its high-temperature stability nature.comNature Communicationsnature.comOpen source ↗.

Results

A single packaged device carried 234 A at 1000 V in pulses. It remained functional at temperatures above 250 °C in the part of the chip where current flows.

The module combining six devices switched 1000 V and 1000 A repeatedly, with fast switching speed and minimal reverse recovery. The authors report a pulsed power capacity density above 1.8 MW/cm², which they say exceeds that of silicon and wide-bandgap semiconductor counterparts.

The authors name industrial, biomedical, grid and aerospace applications as targets for further power scaling. Open questions include how long the module can maintain its performance and whether the packaging can be produced consistently at larger scale. Each application would also set its own requirements for reliability and the number of switching cycles nature.comNature Communicationsnature.comOpen source ↗.