Experimental Characterization of Drain Current Transient Effects in ‘Buffer-Free’ RF GaN HEMTs

Drain current transient measurements performed on an RF GaN HEMT device manufactured using a ‘buffer-free’ technology are compared with those from a corresponding device sharing the same layout and processing steps but utilizing a conventional Fe-doped buffer. A substantially different empirical behavior is observed, that is characterized by a significantly reduced drain-lag and non-monotonic current transients with extended relaxation times.