High performance GaN/AlGaN MODFETs grown by RF-assisted MBE

High performance 0.25 μm gate-length GaN/AlGaN modulation doped field effect transistors grown by RF-assisted MBE on sapphire are demonstrated. A maximum drain current of 750 mA/mm, and a breakdown voltage exceeding 45 V were obtained. Small signal measurement yielded a current gain cutoff frequency of 28 GHz, and a maximum oscillation frequency of 40 GHz. The authors have achieved <5% variation in the maximum drain current across 2 in wafers. These results demonstrated the excellent potential of RF-assisted MBE in the growth of GaN-based microwave power devices for practical applications