THERMAL CONDUCTIVITY MEASUREMENTS OF THE ZnS-SiO_2 DIELECTRIC FILMS FOR OPTICAL DATA STORAGE APPLICATIONS

摘要

The amorphous/crystalline phase formation during writing or erasure of the written marks, in the rewritable phase change (PC) optical recording media, is controlled by the temperature distribution in the media and its variation with time. Temperature distribution, on the other hand, strongly depends on the thermal properties of its constituent layers in particular the ZnS-SiO_2 dielectric layer that separates the phase change media from the substrate and aluminum heat sink. The reported values for the thermal conductivity of thin dielectric layers are however limited in the literature. In this manuscript, we report thermal conductivity data for dielectric layers of thickness near 50, 100 and 225 nm using the steady sate Joule-heating and electrical resistance thermometry technique. The boundary resistance at the interface is estimated to be near 7.0 x 10~(-8) m~2 K W~(-1), which would limit the thermal time constant for cooling of PC layer and potentially impact data rate and jitter in optical recording technology.