High-power AlGaN∕InGaN∕AlGaN∕GaN recessed gate heterostructure field-effect transistors

Abstract

We demonstrate the use of high-quality thin InGaN films as the reactive ion etching (RIE) stop layer for fabrication of recessed gate high-microwave-power AlGaN∕InGaN∕AlGaN∕GaN heterostructure field-effect transistors. We used migration-enhanced-metalorganic-chemical-vapor-deposition grown InGaN layer sandwiched in AlGaN barrier yields better than 10 times RIE selectivity of AlGaN and InGaN compared to our conventional standard AlGaN∕GaN high electron mobility transistors. The fabricated devices exhibited a 50% increase in the breakdown voltage, which is attributed primarily due to the improved electric field distribution at the gate edge and to the increased distance between the AlGaN surface and the device channel. The continuous wave microwave power was measured at the drain bias as high as 60V. The maximum output power and power added efficiency were 8.9W∕mm and 40%, respectively. The obtained results demonstrate a potential of this technique for development of the next-generation high-power transistors.