Phase Transition of Sb-rich Alloy Films under Isothermal and Constant Heating Rate Annealings

Abstract

The phase changed alloy films have great potential applications in the thermal sensor materials beside in the optical and electrical memory materials due to their stable phase transitions. The academic investigation methods on the phase transformation of the phase changed films are annealings either at constant heating rate or isothermal annealing. Both methods are applied and compared for the Sb-rich alloy films. The transitions from amorphous to crystalline of Sb-rich chalcogenide alloys with composition ratio of element group 14 to Sb ranged from 0.46 to 0.17 were investigated. The crystallization temperature at both annealing methods increases with the decrease of the ratio of element group 14 to Sb. The activation energies decided from both annealing methods are comparable, which implies the same crystallization mechanism. The Avrami exponents, ranged between 1.7 and 2.4, are extra values obtained from the isothermal measurements. The 2-D growth mechanism is implicitly dominated by the Avrami exponent values. Sb rhombohedral and Sb 7 Te are the major crystallized phases observed and SnTe and InTe phases are mixed among the major phase matrix when the samples are annealed at 250 o C for 30 min.