Response to vacuum annealing at temperatures up to 600-degrees-C for 3
h for low hydrogen content diamondlike carbon (LHDLC) films prepared b
y magnetron sputtering of pure graphite in pure Ar atmosphere has been
studied. Optical properties of the as-deposited and annealed films ha
ve been characterized by ellipsometry and infrared spectroscopy. No ch
ange was found for the films annealed at up to 400-degrees-C. The LHDL
C begins losing hydrogen after annealing above 400-degrees-C and the s
p2 hybrid structure increases. The refractive index of the films incre
ases with increasing annealing temperatures above 500-degrees-C. Annea
ling at 600-degrees-C results in graphitization and the loss of IR tra
nsparency.