In situ monitoring of target voltage in magnetron reactive sputtering of ZnO

Zinc oxide (ZnO) films were deposited on glass substrates by radio-frequency (RF) magnetron reactive sputtering at room temperature. With the relationship between deposition rate and oxygen flow, the appropriate deposition condition was not set up easily for reactive sputtering. The mechanisms between the sputtered material and the reactive gas may cause some processing stability problems. Therefore, it is required to find the in situ way of determining which mode films would be deposited before deposition. The in situ monitoring of the target voltage during deposition can be helpful for obtaining transparent and conductive films. With the in situ monitoring of the target voltage, the properties of ZnO thin films can be predicted and selected within metallic, transition, and oxide modes.