GaTe-SbTe thin-films phase change characteristics.

A radio frequency magnetron co-sputtering technique exploiting GaTe and ${\rm Sb}2 {\rm Te}3$SbTe targets was used for the fabrication of Ga-Sb-Te thin films. Prepared layers cover broad region of chemical composition (${\sim}{10.0 {-} 26.3},, {\rm at.}$∼10.0-26.3at. % of Ga, ${\sim}{19.9 {-} 34.4},, {\rm at.}$∼19.9-34.4at. % of Sb) while keeping Te content fairly constant (53.8-55.6 at. % of Te). Upon crystallization induced by annealing, large variations in electrical contrast were found, reaching a sheet resistance ratio of ${{R}{\rm annealed}}/{{R}{\rm as - deposited}};\sim{2.2} \times {{10}^{ - 8}}$R/R∼2.2×10 for the ${{\rm Ga}{26.3}}{{\rm Sb}{19.9}}{{\rm Te}{53.8}}$GaSbTe layer. Phase transition from the amorphous to crystalline state further leads to huge changes of optical functions demonstrated by optical contrast values up to $|\Delta n| + |\Delta k| = {4.20}$|Δn|+|Δk|=4.20 for ${{\rm Ga}{26.3}}{{\rm Sb}{19.9}}{{\rm Te}{53.8}}$GaSbTe composition.