GaN transistors brought to market
The superiority of GaN stems from its unique material and electronic properties, making it attractive for electronics and optoelectronics applications. In addition to operating at higher voltages and currents, the switching capability of GaN transistors is up to 10times faster than that of their silicon equivalents. High electron mobility transistors based on GaN have also shown an improvement by a factor of 10in the power density produced at microwave frequencies. While the achieved performance reveals tremendous potential for GaN in a variety of applications, GaN devices have yet not replaced existing technologies. Technical issues such as electron trapping remain to be consistently solved. Drawing on the research resources of the III-V Lab in France, EU-funded researchers availed themselves of state-of-the-art equipment to understand the origin and physical mechanisms involved in trapping effects. Within the framework of the 'Advanced characterisation of electronic properties of gallium nitride based devices' (ELEGAN) project, they found that the influence of traps is greater in transistors operating at high frequencies. In transistors based on thin layers of GaN grown on other materials such as silicon nitride, the drain current was significantly reduced as a result of the trapping effects. The so-called current collapse along with voltage swings ultimately affected the output power. Based on these findings, ELEGAN project fellows prepared GaN-based power bar transistors with normally-off operation. Normally-off operation was strongly desired for the first industrial generation of electrical vehicles designed within the 'Nanoelectronics for an energy-efficient electric car' (E3CAR) project. Moreover, the developed power bar transistors reached the largest drain current ever demonstrated. GaN-based transistors did not only prove to have the characteristics necessary to cope with the advanced power supply and power management designs of E3CAR.ELEGAN has also revealed that market penetration of GaN is well within the realms of near-future possibility, offering exciting new prospects for the European semiconductor industry.
Keywords
Transistors, electronics, gallium nitride, silicon, electric car
