Uncovering the physical properties, structural characteristics, and electronic application of superlattice-like Ti/Sb phase-change thin films

Abstract

Superlattice-like Ti/Sb (SLL Ti/Sb) thin films were proposed and investigated from the points of physical properties, structural characteristics and electronic application. The different structural SLL Ti/Sb thin films with different thickness ratios were deposited by magnetron alternate sputtering. In-situ resistance-temperature measurement indicates that the crystallization temperature, crystallization activation energy and data retention capacity increase significantly and the resistance drift index become smaller with the increment in thickness ratio of Ti to Sb layer, meaning the higher amorphous thermal stability and reliability of SLL Ti/Sb thin films. X-ray diffraction and Raman spectra reveal that the inserted titanium layer can inhibit the grain growth and refine the grain size, causing the remarkable improvement of thermal stability and crystallization rate. The analysis of X-ray reflectivity and atomic force microscopy demonstrate that the thickness fluctuation of SLL Ti/Sb thin films becomes smaller and the surface morphology becomes smoother, comparing with the single Sb layer thin film. The Avrami exponent of (Ti3Sb7)5 thin film reflects the growth-dominated crystallization mechanism, meaning the rapid phase transition rate. PCM cells based on (Ti3Sb7)5 thin film can realize the reversible transition at the electrical pulse with the width of 100 ns and the RESET power consumption is much lower than that of Ge2Sb2Te5. The above results strongly prove that the suitable superlattice-like structure of Ti/Sb phase change films have the tremendous potential application for the electronic storage with high thermal stability and low power consumption.

Enhancing the Thermal Stability and Reducing the Resistance Drift of Sb Phase Change Films by Adding In2Se3 Interlayers

“…As the temperature rose, their resistances began to decline slowly, mainly due to the negative resistance temperature characteristic of the semiconductor. When the temperature rose to T c , both the phase transition temperature [10] and the resistances of the films began to drop sharply, and the amorphous film converted to an ordered crystalline state [11]. The T c of pure Sb is 107 • C, and the T c was gradually increased by adding multiple In 2 Se 3 interlayers.…”