Dependence of Ohmic Contact Resistance on Barrier Thickness of AlN/GaN HEMT Structures

摘要

A multi-faceted study on the reduction of ohmic contact resistance to AlN/GaN-based heterostructures is presented. Minimum contact resistance of 0.5 X mm has been achieved by partially etching the AlN barrier layer using a chlorine-based plasma dry-etch prior to ohmic contact metallization. For thin GaNcapped AlN/GaN heterostructures, we find it is necessary to remove the GaN cap in the vicinity of the contact metal in order to obtain a linear current- voltage relationship. We compare our results of the premetallization etched contacts to those without an etch as well as to results reported in the literature.