Deposition of High Conductivity ITO Films by High Power Pulsed Magnetron Sputtering (HPPMS)

摘要

ITO films were deposited by HPPMS sputtering at room temperature and 300°C. The film properties were compared to properties obtained by conventional DC sputtering. In both cases the film properties were found to strongly depend on the amount of oxygen added to the sputtering gas. In the case of HPPMS sputtering the film properties also strongly depend on the peak power density determined by the charge voltage. For low temperature deposition the HPPMS sputtering process proved to be superior in terms of resistivity obtained for the highest charge voltages used. At 300°C state-of-the-art ITO films are obtained by DC sputtering for optimized oxygen flow using a shielding. For low oxygen flows or without a shielding DC sputtering led to undesired strong spike formation. For HPPMS sputtering without a shielding it was possible to prevent spike formation by using high charge voltages. It was possible to obtain flat films with a lowest resistivity of 135 μΩcm. For in-line production this means that high quality films can be obtained by HPPMS sputtering without the need for a shielding that strongly reduce deposition rate.