A low-temperature remote plasma-assisted oxidation process for interface formation and passivation has been extended from Si and SiC to GaN. The process, which can be applied to nano-scale structures including quantum dots and wires, provides excellent control of ultra-thin interfacial layers which passivate the GaN substrate, preventing a parasitic or subcutaneous oxidation of the substrate during plasma deposition Of SiO2. The remote plasma processing for GaN-SiO2 heterostructures includes: (i) an in situ nitrogen plasma surface clean; (ii) a remote plasma-assisted oxidation for formation of an interfacial GaOx (x = 1.5) transition region between the GaN and deposited dielectric; and (iii) a remote plasma-enhanced chemical vapor deposition of an SiO2 dielectric. (C) 2003 Elsevier Science B.V. All rights reserved.