Investigation on the crystallization properties and structure of oxygen-doped Ge8Sb92 phase change thin films

Abstract

Effects of oxygen incorporation on the crystallization characteristics and crystal structure of Ge8Sb92 films were systematically investigated. The amorphous-to-crystalline transition was studied by in situ resistance measurement. The thermal stability, electrical resistance and band gap of Ge8Sb92 material increase significantly by the addition of oxygen. X-ray diffraction, transmission electron microscopy and x-ray photoelectron spectroscopy illustrate that a small amount of oxygen dopant can inhibit the grain growth and limit the grain size because of the formation of Ge and Sb oxide. Atomic force microscopy and x-ray reflectivity results indicate that the film surface becomes smoother and the film thickness change becomes smaller after oxygen doping. Phase change memory cells based on oxygen-doped Ge8Sb92 film were fabricated to evaluate the electrical properties as well. All the results demonstrate that suitable incorporation of oxygen is an effective way to enhance the comprehensive performance of Ge8Sb92 thin films for phase change memory application.