Characteristics of a-C/B:H films from non-toxic o-carborane vapor prepared by using DC glow discharges

A non-toxic boron-containing material, carborane (C 2 B 10 H 12 ), has been utilized to deposit amorphous hydrogenated carbon/boron (a-C/B:H) thin films in helium DC glow discharges. The helium plasma was produced at a target pressure of ∼5 mTorr in the pulsed mode at a duty cycle of 0.375 (3 s on/5 s off) or 0.23 (3 s on/10 s off) by using a filament discharge system connected with a carborane evaporation source. Deposited a-C/B:H thin films were characterized by using variable angle spectroscopic ellipsometry, scanning electron microscopy, Auger electron spectroscopy, and X-ray photoelectron spectroscopy. The a-C/B:H thin films have soft polymer-like characteristics with optical constants of n = 1.65 and k = 10 −3 at 632 nm, and the B/C ratio inside the bulk was ∼2 for an ∼60% boron contents. The evaporation characteristics of carborane powder under vacuum were also investigated.