Temporal evolution of Ti sputtered species number densities in multi-pulse HiPIMS process

The major drawback of HiPIMS technology is typically lower deposition rate in comparison with dc magnetron sputtering for the same average applied power. Significant increase of the deposition rate can be achieved by using HiPIMS in multi-pulse operation mode [1]. We found that the ion flux to the substrate increased by 37% just by rearranging the pulses in the multi-pulse HiPIMS. The absolute ground state number densities of sputtered Ti atoms and ions were determined spectroscopically by an on-site developed effective branching fraction method [2]. The influence of different delays (200µs, 400µs and 1500µs) between successive pulses on the temporal evolution of Ti and Ti+ in the pulse sequence was thoroughly investigated. It was concluded that the residual Ti atoms and ions originating from the preceding pulse assisted faster ignition of the subsequent pulse. Beside enhanced deposition rate of the multi-pulse HiPIMS, certain fraction of the atoms sputtered by the preceding pulse was ionized by the subsequent pulse which resulted in beneficial higher ion bombardment of the growing film.