Single Crystal Al Interconnects Formed on p-GaN and Their Application to GaN FET

A new technology for manufacturing a GaN FET is proposed and demonstrated. A Ti/AI/Ti stack contacting to p-GaN is used as a gate metal. Surprisingly, Al forms a single crystal on p-GaN. The single crystal formation is due to an epitaxial growth of Al on p-GaN. Sheet resistance of the Ti/AI/Ti stack is decreased by the single crystal formation. Electromigration lifetime is drastically improved with the fraction of the single crystal. In addition, the Ti/AI/Ti stack shows very low contact resistance to p-GaN.