Room-temperature plasma-enhanced atomic layer deposition of ZnO: Film growth dependence on the PEALD reactor configuration

Room-temperature plasma-enhanced atomic layer deposition (PEALD) of ZnO was studied by depositing the films using diethylzinc and O2 plasma from inductively-coupled plasma (ICP) and capacitively-coupled plasma (CCP) plasma source configurations. The CCP-PEALD was operated using both remote and direct plasma. It was observed that the films deposited by means of remote ICP and CCP were all highly oxygen rich, independently on plasma operation parameters, but impurity (H, C) contents could be reduced by increasing plasma pulse time and applied power. With the direct CCP-PEALD the film composition was closer to stoichiometric, and film crystallinity was enhanced. The ZnO film growth was observed to be similar on silicon, polycarbonate and poly(methyl methacrylate) substrates, but changes in polymer surface morphology indicate plasma-induced damage during the deposition due to exposure to ion bombardment when direct plasma was applied.