Characteristics of low-resistivity aluminum-doped zinc oxide films deposited at room temperature by off-axis radio-frequency sputtering on flexible plastic substrates

On the grain size-thickness correlation for thin films

“…Again when the surface features are small enough, several authors report a good agreement with XRD: for SEM [46,47] and for AFM [48][49][50][51] . In contrast, some other studies have reported that the grain size determined by microscopy technique is much larger than the domain size obtained by XRD: for SEM [52] , for AFM [53][54][55][56][57] , and for STM [58] . Some of the aforementioned researchers reasoned that the grains are composed of several domains separated by low-angle grain boundaries [53,55,58,59] .…”

Lowering the resistivity of aluminum doped zinc oxide thin films by controlling the self-bias during RF magnetron sputtering

“…While a race for very low J o u r n a l P r e -p r o o f resistivity values is still ongoing, practical applications such as solar cells, smart windows and touch panels, require from moderate to excellent optoelectronic properties (depending on specific application) obtained over an area comparable with the magnetron cathode surface. Several attempts have been made to avoid the negative ions during AZO deposition, including facing target sputtering [34], cathode tilt [35], off axis deposition [36] or magnetic field deflection when operating the discharge in high power impulse magnetron mode [37]. Despite of not knowing the exact mechanism of AZO thin film growth, this work demonstrates that lowering the DC self-bias below 100 V can improve the resistivity with a factor larger than 2 not only for certain locations on the substrate but over and area almost equal with that of the magnetron cathode.…”