Performance improvement of ohmic contacts on Al-rich n-AlGaN grown on single crystal AlN substrate using reactive ion etching surface treatment

摘要

Four orders of magnitude improvement in specific contact resistivity of Al-rich n-AlGaN grown on single crystal AlN substrates is achieved by surface treatment based on reactive ion etching (RIE). The ohmic contacts to as-grown Al-rich n-AlGaN/AlN exhibit a high contact resistance and nonlinearity due to a large Schottky barrier and low dislocation density. The RIE surface treatment reduces the barrier height at the free surface by similar to 0.5 eV and is also expected to introduce a defective surface required for ohmic contact formation. (C) 2017 The Japan Society of Applied Physics