Preparation of silicon-doped diamond-like carbon films with electrical conductivity by reactive high-power impulse magnetron sputtering combined with a plasma-based ion implantation system

Abstract

Silicon-doped diamond-like carbon (Si-doped DLC) films were prepared by a reactive high-power impulse magnetron sputtering (HiPIMS) combined with a plasma-based ion implantation (PBII) system, in which tetramethylsilane (TMS) was used as a reactive gas. The preparation of the Si-doped DLC films was based on both plasma-enhanced chemical vapor deposition and physical vapor deposition. The incident energy of the reactive ions was controlled by applying negative pulse voltage to the substrate using the PBII system. The Si content was controlled by the flow rate ratio of TMS to Ar. The negative pulse voltage was crucial because the resistivity of Si-doped DLC films prepared under the conditions of an Ar flow rate of 75 sccm and a TMS flow rate of 1.5sccm exponentially decreased from 575 to 30 Ωcm with an increase in the negative pulse voltage in the voltage range up to −7 kV. Through X-ray photoelectron spectroscopy, it was estimated that the Si content in the films ranged between 4.3% and 11% in our experiment. The resistivity of the films, which were prepared at a negative pulse voltage of −5 or − 7 kV in the range of the flow rate ratio up to 0.043, markedly increased from 3 to 380 Ωcm with an increase in the Si content. Moreover, the film hardness ranged between 9 and 16 GPa.