Development of a high transconductance GaN MMIC technology for millimeter wave applications

Abstract In this paper we report on the development of high transconductance GaN‐based high electron mobility transistors (HEMTs) to improve the performance at W‐Band frequencies. At first, the influence of the barrier thickness on the maximum transconductance (gm,max) was investigated by using two different technologies: growth of thin barrier layers and deep gate recess. Second, the effect of a gate length reduction down to 100 nm on gm,max was examined. The reduction of the barrier thickness results in a strong increase of the extrinsic transconductance up to 600 mS/mm. The technology was then used to fabricate HEMTs, with a cut‐off frequency of 110 GHz, which are compatible to a MMIC technology (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)