Structure and optical properties of plasma immersion ion processed boron-alloyed diamondlike carbon films

Abstract

Boron (B)-alloyed diamondlike carbon (B-DLC) films were prepared on polymethyl methacrylate (PMMA), glass, and silicon (100) using an inductive radio frequency Ar + C2H2 + B2H6 plasma immersion ion processing (PIIP) technique. The composition of the B-DLC films was measured by ion beam analysis techniques, and the bonding structure was characterized by infrared and Raman spectroscopy. The incorporation of B2H6 gas into the PIIP deposition introduced B-C bonds into the DLC structure, resulting in increased sp3-carbon bonding and improved optical performance. The energetic activation of the deposition atoms, induced by the ion bombardment during the PIIP film growth, enhanced the properties of the B-DLC films deposited on dielectric and transparent optical materials. With B-alloying and an optimized deposition energy of 40–135 eV, B-DLC films were synthesized with B-alloying up to 10.4 at.%, high hardness, high refractive index, and optical transmittance that is higher than that of unalloyed DLC films. The experimental results indicate that C-B hybridization and ion-energy transfer are critical to the synthesis of these hard and transparent B-DLC films.