Gallium oxide offers promise for power electronics

January 12, 2017 // By Peter Clarke
A semiconductor material known as beta gallium oxide (Ga2O3) could be of benefit in high-voltage applications if its poor thermal properties can be overcome.

A research team from Purdue University (Lafayette, Indiana) has reported on the performance characteristics of a field effect transistor (FET) made in a thin film of beta gallium oxide on insulator (GOOI) in a paper published in IEEE Electron Device Letters.

The ultra-wide band gap of the material makes it efficient for high-voltage switching and the efficiency could help reduce energy use by replacing less efficient power switches typically implemented in silicon.

The schematic at left shows the design for an experimental transistor made of a semiconductor called beta gallium oxide. At right is an atomic force microscope image of the semiconductor. Source: Peide Ye/Purdue University

The transistor has a current on/off ratio of 10^10 and a subthreshold voltage roll off 140mV/decade when laid down on 300nm thick silicon dioxide. E-mode GOOI FET with source to drain spacing of 0.9 μm demonstrates a breakdown voltage of 185V and an average electric field (E) of 2 MV/cm, showing the promise of GOOI FET for future power devices.

The team also developed a low-cost method to produce layers of Ga2O3. Similar to the way graphene can be produced, adhesive tape can be used to peel off layers of the semiconductor from a single crystal.

To get round the poor thermal properties of the material future research will focus on attaching the material to heatsink substrate such as diamond or aluminum nitride.

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