TixSb2Te Thin Films for Phase Change Memory Applications

Sb2 Te films with different Ti contents （TixSb2 Te） are derived via the target-attachment method by using the magnetron sputtering technique. The effects of the Ti content on the phase change characteristics and the microstructures are investigated by x-ray diffraction, x-ray photoelectron spectroscopy, scanning electron microscopy and atom force microcopy. Resistance-temperature measurements are carried out to reveal the enhanced crystallization temperature of TixSb2 Te films, indicating a better thermal stability in such films. Both the activation energy and the temperature for 10 y data retention increase with increasing the concentration of Ti. It indicates that the crystallization of the amorphous Sb2 Te film could be suppressed by the introduction of Ti. The improvement of crystallization temperature and the thermal stability of the amorphous Sb2 Te film results from the introduction of Ti in Sb- Te bond that decreases the binding energy of Sb 4d and Te 4d.     

The Distinguished Charge-Trapping Capability of the Memory Device with Al2O3-Cu2O Composite as the Charge Storage Layer

A memory device Si/Al2O3/Al2O3-Cu2O/Al2O3/Pt is fabricated by using atomic layer deposition and r~magnetron sputtering techniques. The memory device including the composite of Al2O3 and Cu2O as the charge storage layer shows a distinguished charge trapping capability. At a working voltage of ±11 V a memory window of 9.22 V is obtained. The x-ray photoelectron spectroscopic study shows a shoulder from Cu2＋ ions around the peak of Cu1＋ ions. It is suggested that the charge-trapping mechanism should be attributed to the defect states formed by the inter-diffusion at the interface of two oxides.