The role of hydrogen in a-C:H films deposited from hexane or acetylene using direct ion beam deposition method

Abstract

The present work provides results of amorphous hydrogenated carbon (a-C:H) films deposited by direct ion beam deposition method. Hexane (C 6H 14+H delivery) or acetylene (C 2H 2) precursors and their mixture with hydrogen (H 2) were used. The films were characterized by Raman spectroscopy (RS), ellipsometry, and electrical resistance measurements. RS indicates increase in sp 3/sp 2 bonding ratio and disorder in graphite clusters, upon increasing of hydrogen content (from 0% to 50% for acetylene precursor) in the deposition gas mixture. The opposite trend is observed when the hydrogen concentration exceeded 50% (for acetylene) or additional hydrogen was added (for hexane). The data of electrical resistance measurements support the correlations defined by RS.