imec develops GaN on Si fet

Belgian research centre IMEC has developed a GaN on Si double heterostructure FET architecture for power switching devices. The architecture, which meets the normally off requirements of power switching circuits, is characterised by low leakage and high breakdown voltage.

Although high voltage power devices are traditionally based on silicon mosfets, these have, in a number of applications, reached intrinsic material limits. GaN compounds offer a route forward due to their high band gap and high electrical breakdown field. But the devices are expensive. According to IMEC, GaN epilayers grown on large diameter silicon wafers may offer a lower cost approach than other substrates. Using the GaN on Si approach, IMEC has demonstrated breakdown voltages of almost 1000V, combined with low on resistance, using a SiN/AlGaN/GaN/AlGaN double heterostructure FET structure on a silicon substrate. These results, says IMEC, hold the promise of a huge market opportunity for GaN on Si power devices.