Top-Down Fabrication of Large-Area GaN Micro and Nano Pillars
Albert Davydov, Ratan K. Debnath, B. Wen, Dipak Paramanik, Abhishek Motayed, M. King
Large-area gallim nitride (GaN) nanopillars (NPs) arrays were fabricated by plasma etching of lithographically patterned GaN thin-film grown on Si substrate. Deep-UV lithography, inductively-coupled plasma etching, and follow-on chemical treatments were effectively utilized to fabricate GaN pillars with diameters ranging from 250 nm to 10 um. Effect of various plasma etching process parameters and chemical etchants on the morphology, strain and surface defects of these NPs were studied using scanning-electron microscopy (SEM), photoluminescence (PL), and Raman scattering. It was found tht the final shape of the NPs can be controlled by the substrte temperature during the plasma etch and using different gas chemistries. Room-temperature PL and Raman scattering measurements reveled significant strain relaxation in 250 nm diameter etched pillars as compared to 10 um diameter pillars. Room temperature PL measurement suggested that the surface damage due to plasma etch can be removed by subsequent etching in KOH-ethylene glycol solution. Post plasma etch chemical treatment not only removed the surface damage but also enabled us to fabricate functional structures such as micro- and nano-disks of GaN, which could be potentially useful in nitride-based resonators and lasers.
, Debnath, R.
, Wen, B.
, Paramanik, D.
, Motayed, A.
and King, M.
Top-Down Fabrication of Large-Area GaN Micro and Nano Pillars, Journal of Vacuum Science and Technology B
(Accessed December 9, 2023)