Gareth Bellinger¹, Peter van Nooten², Jacek Wojcik², Simran¹, Marek Niewczas^1
1McMaster University, Hamilton, Ontario, Canada
²Intlvac Thin Film Inc., Georgetown, Ontario, Canada
Diamond-like Carbon (DLC) is gaining attention for application in new generation technologies such as bipolar plates in hydrogen fuel cells and optoelectronic lenses in infrared (IR) devices. DLC is a hydrogenated, amorphous form of carbon containing bonding characteristics of both diamond (sp3) and graphite (sp2). Variation of the bonding and hydrogen content allows significant changes to the films' physical and chemical properties, which exhibit high mechanical hardness, superior wear resistance, and IR transparency, among other unique properties. The maturity of deposition processes has enabled tuning these properties, expanding DLC applications to various industries, including biomedical, aerospace, and automotive. Characterizing both the chemical bonding configuration and the hydrogen content is essential to devise processing conditions for the synthesis of these materials with desired properties. This work focusses on characterization of DLC films produced by PECVD over a range of applied self-bias conditions and with variation of standard industry precursor gases. Mechanical and tribological properties were obtained using nanoindentation and scratch testing. Chemical bonding information was obtained using X-ray Photoelectron Spectroscopy (XPS) and X-ray excited Auger Electron Spectrometry (XAES) methods in conjunction with Raman spectroscopy. Finally, Elastic Recoil Detection Analysis (ERDA) was used to quantify the hydrogen content of the films. Raman spectroscopy is shown to be the technique of choice for prediction into the sp3 bonding character, hydrogen content, and hardness when compared to quantitative results obtained from XPS, ERDA, and nanoindentation. Tailoring the self-bias allows for DLC films that exhibit mechanical hardness over 20 GPa, suitable as protective optical coatings or in low friction applications.