AlGaN/GaN microwave HFET including a thin AlN carrier exclusion layer

A study of the effect of the insertion of a thin AlN exclusion layer between the AlGaN and GaN buffer layer in microwave hetero-junction field effect transistor structures grown by MOVPE on sapphire and SI-SiC substrates is presented. A dramatic improvement in carrier drift mobility is observed and we present evidence from CV analysis that this improvement is associated with reduced penetration of the 2D electron gas into the AlGaN. (© 2003 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)