Radio-frequency magnetron co-sputtered Ge-Sb-Te phase change thin films

Radio-frequency magnetron co-sputtering technique with GeTe and Sb2Te3 targets has been used for the deposition of Ge-Sb-Te amorphous thin films. Fabricated layers cover broad region of chemical composition (-17.435.0 at. % of Ge, -14.2-29.0 at. % of Sb) with slight variation in Te content (50.8-53.6 at. % of Te). Upon annealing-induced crystallization, large variations in electrical contrast up to eight orders of magnitude were found. Phase change from amorphous to crystalline state leads also to drastic changes of optical functions demonstrated by optical contrast values up to |delta n|+|delta k| = 2.96 for GeTe layers at Blu-ray wavelength. Reflectivity contrast at Blu-ray wavelength reaches up to -43% with increasing content of GeTe in Ge-Sb-Te thin films, confirming importance of GeTe content in Ge-Sb-Te thin films.