Physico-chemical properties of Sb-rich (Sb, In)-Te thin films

The phase change materials of the system Sb70−xInxTe30 (x = 0, 7 and 14) were studied. The thin films prepared by thermal flash evaporation were amorphous with high electrical sheet resistance (Rs) (≈106 Ω/sqr., T = 300 K). When heated, the resistance dropped to 10-102 Ω/sqr. due to crystallization of the films. The crystallization temperatures were 113, 158 and 183 °C for Sb70Te30, Sb63In7Te30 and Sb56In14Te30, respectively. The activation energies of crystallization as evaluated by Kissinger's plot were 2.42, 2.72 and 3.15 eV for Sb70Te30, Sb63In7Te30 and Sb56In14Te30, respectively. The optical band gap of amorphous films increases with increasing content of indium from 0.38 to 0.47 eV. Values of refractive index were found in range of 5.43-4.77 (λ = 1500 nm) for amorphous state and 7.06-5.89 for crystalline state in dependence on composition. They decreased with increasing content of indium.