Semiconductor eyed for next-generation ‘power electronics’

semiconductor

The schematic on the left shows the design for an experimental transistor made of a semiconductor called beta gallium oxide, which could bring new ultra-efficient switches for applications such as the power grid, military ships and aircraft. On the right is an atomic force microscope image of the semiconductor. Image: Purdue University/Peide Ye

Researchers have demonstrated the high-performance potential of an experimental transistor made of a semiconductor called beta gallium oxide, which could bring new ultra-efficient switches for applications such as the power grid, military ships and aircraft.

The semiconductor is promising to enable next-generation “power electronics,” or devices needed to control the flow of electrical energy in circuits. Such a technology could help to reduce global energy use and greenhouse gas emissions by replacing less efficient and bulky power electronics switches now in use.

The transistor, called a gallium oxide on insulator field effect transistor, or GOOI, is especially promising because it possesses an “ultra-wide bandgap,” a trait needed for switches in high-voltage applications.

Compared to other semiconductors thought to be promising for the transistors, devices made from beta gallium oxide have a higher “breakdown voltage,” or the voltage at which the device fails, said Peide Ye, professor of electrical and computer engineering at Purdue University.

Along with graduate student Hong Zhou, Ye also developed a new low-cost method using adhesive tape to peel off layers of the semiconductor from a single crystal, representing a far less expensive alternative to a laboratory technique called epitaxy. The market price for a 1cm x 1.5cm piece of beta gallium oxide produced using epitaxy is about US$6,000. In comparison, the “Scotch-tape” approach costs pennies and it can be used to cut films of the beta gallium oxide material into belts or “nano-membranes,” which can then be transferred to a conventional silicon disc and manufactured into devices, according to Ye.

The technique was found to yield extremely smooth films, having a surface roughness of 0.3 nanometers, which is another factor that bodes well for its use in electronic devices, said Ye.

The Purdue team achieved electrical currents 10 to 100 times greater than other research groups working with the semiconductor, according to Ye.

One drawback to the material is that it possesses poor thermal properties. To help solve the problem, future research may include work to attach the material to a substrate of diamond or aluminium nitride.