Comparative study of structure, optical properties and residual stress of boron carbide thin films deposited by RF-PECVD and PLD technique

Abstract Boron carbide (BxC) thin films deposited using Radio-Frequency Plasma Enhanced Chemical Vapour Deposition (RF-PECVD) and Pulsed Laser Deposition (PLD) techniques were investigated to compare crystallinity, chemical composition, optical properties, and residual stress. The film deposited by PLD was amorphous, while PECVD technique yielded crystalline BxC film. Better stoichiometric purity was obtained via PLD technique, with B4C being the most dominant phase as observed in XPS spectra. Super-stoichiometric phase (BxC (x > 4)) was dominant in PECVD deposited film. Moreover, PECVD film had greater adhesion (Lc3 ∼29.5 N), hardness (∼2798 HK), and lubricity (COF∼ 0.03) in comparison with PLD deposited film. Optically, higher value of refractive indices (1.82 at 600 nm) and lower extinction coefficient was measured for PECVD deposited film. Estimated rresidual stress for PLD 400 C film was compressive in nature while the same for PECVD -100 V film was tensile, with 10 times less in magnitude in comparison. This study provides the user with opportunity to weigh the advantages and disadvantages of PECVD and PLD techniques for deposition of functional BxC films.