Growth and characterization of DH‐HEMT structures with various AlGaN barriers and AlN interlayers on 200 mm Si(111) substrates

Abstract

AbstractAlGaN/GaN/AlGaN double heterojunction high‐electron‐mobility transistors were grown on 200 mm Si (111) using metalorganic chemical vapor deposition. The Al composition of AlGaN barrier varied from 20 at% to 30 at% and thickness from 10 nm to 20 nm. In some structures, a 1 nm AlN interlayer was inserted between AlGaN barrier and GaN channel. The as‐grown wafers were proven to be of high material quality and the layer thickness were well controlled to the target values. A buffer break down voltage of over 700 V were obtained for all grown wafers. Compared to their counterparts without AlN interlayer, structures with AlN interlayer showed a much lower and more uniform two‐dimensional electron gas sheet resistance. With the presence of AlN interlayer, the sheet resistance was much less sensitive towards variations in AlGaN barrier composition and thickness. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)