Effect of Deposition Power on DLC Structure on Alumina in RF-Biased Inductively Coupled Plasma

Abstract

Diamond-like carbon (DLC) coating can improve the material surface's friction performance and interfacial compatibility. The current process for DLC deposition on alumina is inadequate, and the effect of deposition power on DLC structure is still unclear. In this paper, the RF-biased inductively coupled plasma (ICP) was introduced to enhance DLC deposition on alumina. By studying the morphology and bonding structure of films under different power conditions, the effects of total power and bias power fraction on DLC structure were decoupled, and the dominant mechanism determining the behavior of the sp2 phase in the films was investigated. The results show that the increase of total power and bias power fraction led to a decrease in the fraction of sp3 hybridized carbon in films, and partition phenomena with increasing internal stress. As the total power increased from 90 W to 180 W, the variation trend of sp2 clusters and CH groups with the bias power fraction reversed, which reflected that the dominant effect factor for deposition changed from implanted ion energy to thermal spike accumulation. The study deepened the understanding of the DLC formation process under plasma action.