12.88W/mm GaN High Electron Mobility Transistor on Silicon Substrate for High Voltage Operation

We have demonstrated the highest RF output power density of 12.88W/mm, to our knowledge, at 2.14 GHz in GaN high electron mobility transistor on silicon (Si) substrate at high voltage operation. This highest record was achieved by reducing the parasitic loss at the conductive interface layer between the epitaxial structure and the Si substrate, and thinning the Si substrate thickness. The parasitic loss evaluation by a capacitance-voltage method proved to be effective since the epitaxial wafer selection is possible without fabricating RF devices. Si substrate as thin as 60 mu m results in good thermal resistance and contributes to the large RF output power density. (C) 2009 The Japan Society of Applied Physics