Hydrogenation of ZnO:Al Thin Films Using Hot Filament

Abstract

ZnO : Al films were prepared through the optimization process of aluminum content and substrate temperature in rf-magnetron sputtering. When hydrogenation was performed on these films using a hot filament method, all films showed improvement in conductivity although more conductive film showed less improvement. When the substrate temperature (T_H) was varied from 25℃ to 300℃ during hydrogenation, the resistivity was reduced more at higher T_H but the recovery of resistivity was observed upon the extinction of hot filament. This dehydrogenation was caused by the hydrogen evolution out of the film and it was more severe at higher T_H (more than 30% at T_H = 300℃) Thus, two methods were developed to suppress the dehydrogenation in ZnO : Al films: (1) capping with amorphous silicon thin film as a diffusion barrier, and (2) cooling during hydrogenation.