Side gate AlGaN/GaN FET on silicon and sapphire

Abstract

AbstractAlGaN/GaN heterostructures were grown on sapphire and alternatively on silicon substrates covered with a thin SiC layer by MOCVD. The side gated transistors were fabricated using electron beam lithography. The conductivity of the drain‐source branch could be tuned via the side gate formed by a two‐dimensional electron gas directly connected to the source drain branch or separated by a trench.The electrical measurements of the fabricated in‐plane‐gated devices revealed unipolar transistor behavior for both types of substrates. The transconductance was 1 µA/V and the output conductance reached 1.9 µA/V for the side gate transisitor on sapphire. The transconductance and output conductance of the side gate device on silicon substrates were 6 and 18 µA/V, respectively. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)