Characterization of AlGaN/GaN HEMT devices grown by MBE

Ammonia-MBE growth techniques were developed to allow the production of AlGaN and GaN layers suitable for electronic applications on sapphire [000] substrates. DC and RF characterization of AlGaN/GaN HEMT devices have been carried out over a temperature range from -40\ub0C to 200\ub0C. The devices characterized were two finger 7 50 \ub5m wide designs with measured gate lengths ranging from 1 \ub5m to 3.5 \ub5m. Hall and CV measurements indicate a 2DEG sheet charge density at the AlGaN/GaN heterojunction interface as high as 1.9 710\ub9\ub3/cm\ub2 and 1.5 710\ub9\ub3/cm\ub2 respectively. Low field mobilities in excess of 950 cm\ub2/V 7s have been measured. Room temperature measurements for a device with a gate length of 1 \ub5m and Vds set to 10 V exhibited a pinch off voltage of -5 volts. A maximum drain current of 946 mA/mm and a peak transconductance of 160 mS/mm were also measured. The off state drain to source breakdown voltage is 33 volts. Room temperature RF characterization with Vds=10 volts indicate intrinsic device fT and fMAX to be 15.6 GHz and 49.4 GHz respectively. At maximum power dissipation and chuck temperature, the channel temperature is estimated to be >320\ub0C.NRC publication: Ye