GaTe–Sb₂Te₃ thin-films phase change characteristics

Abstract

A radio frequency magnetron co-sputtering technique exploiting GaTe and S b 2 T e 3 targets was used for the fabrication of Ga–Sb–Te thin films. Prepared layers cover broad region of chemical composition ( ∼ 10.0 − 26.3 a t . % of Ga, ∼ 19.9 − 34.4 a t . % 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 a n n e a l e d / R a s − d e p o s i t e d ∼ 2.2 × 10 − 8 for the G a 26.3 S b 19.9 T e 53.8 layer. Phase transition from the amorphous to crystalline state further leads to huge changes of optical functions demonstrated by optical contrast values up to | Δ n | + | Δ k | = 4.20 for G a 26.3 S b 19.9 T e 53.8 composition.