Behavior of GeSbTeBi phase-change optical recording media under subnanosecond pulsed laser irradiation.
We investigated the variations in reflectivity during the phase transition between amorphous and crystalline states of a Bi-doped GeTe-Sb2Te3 pseudobinary compound film with subnanosecond laser pulses, using a pump-and-probe technique. We also used a two-laser static tester to estimate the onset time of crystallization under 2.0-micros pulse excitation. Experimental results indicate that the formation of a melt-quenched amorphous mark is completed in approximately 1 ns, but that crystalline mark formation on an as-deposited amorphous region requires several hundred nanoseconds. Simple arguments based on heat diffusion are used to explain the time scale of amorphization and the threshold for creation of a burned-out hole in the phase-change film.
Core Technology Center, Toshiba Corporation, 8, Shinsugita-cho Isogo-ku, Yokohama 235-8522, Japan. kazuo.watabe@toshiba.co.jp
Kazuo
K
Watabe
Pavel
P
Polynkin
Masud
M
Mansuripur