Current status on GaN-based RF-power devices

In this paper, we review the recent advances of GaN power switching and RF transistors developed at Panasonic. The presented devices are formed on cost effective Si substrates, which are very promising for the future mass production contributing to the reduction of the total fabrication cost. We develop the epitaxial growth technology using metal organic chemical vapor deposition (MOCVD) over 6-inch Si substrates by novel buffer layers relaxing the stress caused by the lattice and the thermal mismatches. Aiming at the power switching applications, we propose a new device structure called Gate Injection Transistor (GIT) for strongly desired normally-off operation together with low on-state resistances. The GITs are applied for an inverter to drive a motor which exhibits high operating efficiencies. Further increase of the breakdown voltages up to 2200 V on Si is achieved by a novel Blocking Voltage Boosting (BVB) structure which prevents the inversion elections at the AlN/Si flowing at the periphery of the chips. As for the RF devices, we present 203W output power at 2.5GHz and 10.7W at 26.5GHz by AlGaN/GaN devices on Si. These GaN-based switching and RF power devices on Si substrates are very promising for a variety of applications taking advantages of their inherent low cost with superior performances.