Ion kinetic energy control in dual plasma deposition of thin films

Dual plasma deposition based on plasma immersion ion implantation and plasma deposition is a fledgling technique for the fabrication of functional thin films. One of its advantages is the easy adjustment of the ion kinetic energy during the process. It is straightforward to control the ion kinetic energy during the fabrication of conducting thin films on conducting substrates by simply varying the negative dc voltage applied to the targets. However, for the fabrication of insulating thin films or film deposition on insulating substrates, charge accumulation makes it difficult for ions to attain the proper kinetic energy. In these cases, a pulse or ac voltage is commonly employed. In this article, we theoretically investigate the process window in dual plasma deposition with respect to the pulse width and frequency of the applied voltage to avoid electrical breakdown of the film as well as large ion kinetic energy deviation. The model can deal with the deposition of insulating thin films on conducting or insulating substrates.