Thickness effect on the crystallization characteristic of RF sputtered Sb thin films

The monobasic Sb thin films with different thicknesses were prepared by radio frequency magnetron sputtering. The evolutions of Sb thin film from the amorphous state to the crystalline state were studied by in situ resistance–temperature measurement system. The crystallization temperature, electrical resistance, crystallization activation energy, and data retention capacity of Sb thin films increase significantly with the decrease of film thickness. The optical band gap energy increases and the surface become smoother. The analysis of X-ray diffraction indicates that the grain size becomes smaller and the crystallization may be inhibited by decreasing the film thickness. The prototype phase-change memories based on Sb thin films with different thicknesses were fabricated by CMOS technology. The electrical performances of phase-change memory show that the thinner Sb films have the larger threshold switching voltage and smaller RESET operation voltage, which means the better thermal stability and lower power consumption. The outcomes of this work provide the guidance for designing high-density phase-change memory by reducing the size of Sb thin film.