Low Resistance High Reflectance ITO/Al Ohmic Contacts to p-Type GaN Via SF6 Plasma Treatments

Abstract

We demonstrate improved electrical and optical properties of indium tin oxide (ITO)/Al reflectors, via SF6 plasma treatments, for vertical-type GaN light emitting diodes. A 200 nm thick ITO film was deposited and annealed at 650 degrees C to obtain ohmic contacts with p-GaN, after which SF6 and O-2 plasma were applied on ITO before the Al deposition to effectively increase the work function of ITO and decrease the roughness of the ITO surface. The SF6 plasma-treated ITO/Al reflector showed the lowest specific contact resistance of 9.83 x 10(-4) Omega cm(2) and the highest reflectance of 91% at 460 nm, compared to as-deposited and O-2 plasma-treated ITO/Al reflectors. (C) 2010 The Electrochemical Society. [DOI: 10.1149/1.3290733] All rights reserved.