Dependence of Ohmic Contact Resistance on Barrier Thickness of AlN/GaN HEMT Structures
NAVAL RESEARCH LAB WASHINGTON DC
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A multi-faceted study on the reduction of ohmic contact resistance to AlNGaN-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 AlNGaN 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.
- Inorganic Chemistry
- Electrical and Electronic Equipment