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

Abstract

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