MOCVD-grown 0.25- mu m MESFET's using tertiary butyl arsine as the arsenic source

Abstract
High-performance 0.25- mu m-gate MESFETs on MOCVD-grown epitaxial structure have been fabricated using tertiary butyl arsine (TBA) as the arsenic source. TBA, a liquid-phase organometallic arsenic compound, is a promising alternate arsenic source due to its lower vapor pressure, which makes it safer to handle than arsine. DC characterizations show that the extrinsic peak transconductance is 508 mS/mm. From on-wafer S-parameter measurements, the MESFETs show a current-gain cutoff frequency of 55 GHz and a maximum-available-gain cutoff frequency of 93 GHz. These results represent the best results reported for MOCVD-grown MESFETs using a TBA source and compare favorably with the previously reported f/sub t/ of 40 GHz for molecular beam epitaxy (MBE)-grown MESFETs.