Compositional dependence of optical constants and microstructures of GeSbTe thin films for compact-disc-rewritable (CD-RW) readable with conventionalCD-ROM drives

We studied the dependence of optical constants and microstructures of (GeTe )(x)(Sb2Te3)(1-x) films on composition to determine the optimal composition of phase change recording materials. The maximal differences in optical co nstants between crystalline and amorphous phases and the minimal crystallin e grain sizes of the films were obtained at Ge39Sb10Te51. Using Ge39Sb10Te5 1 as a recording layer and TiO2 and SiO2 as interference layers, a compact disc rewritable (CD-RW) with 65% reflectivity and 60% modulation was obtain ed.