Atmospheric aging and thermal annealing effects in a-C:H thin films

Atmospheric aging and thermal annealing effects have been studied in hydrogenated amorphous carbon (a-C:H) thin films deposited using a de saddle field glow discharge technique with different ion energies (85-225 eV) during deposition. The a-C:fl films grown with low ion energies showed aging effects when they were exposed to the ambient atmosphere. Infrared (IR) absorption due to O-H and C=O vibration modes increased while the IR absorption due to C-H vibrations decreased with aging. The absence of absorption due to O-D vibrations in deuterated films indicates that the films reacted with water rather than oxygen when exposed to the atmosphere. The C-H and O-H bond concentrations decreased when the a-C:H films which had been exposed to the atmosphere for a one month period were thermally annealed. The a-C:H films grown with high ion energies exhibited neither atmospheric aging nor thermal annealing effects. (C) 2000 Elsevier Science B.V. All rights reserved.