The <00l>-oriented growth of Cu2S films and its switching properties
Cu2S films have been deposited on Pt/TiO2/SiO2/Si(111) substrates, and annealed at different temperatures in a vacuum chamber. They were characterized by using X-ray diffraction and scanning electron microscopy. It was observed that the Cu2S films deposited at room temperature are well crystallized and the grains are oriented along different directions. With the increase of the annealing temperature, the grains of Cu2S films prefer the <00l>-orientations, and the average size of Cu2S films decreases. After annealed at 400°C, the films are completely <00l>-oriented, and the grain boundaries of Cu2S films become undistinguishable due to the possible movements of the ions at high temperature. The resistive ratio of the ‘off’ state to the ‘on’ state is about 107 for the memory unit of Cu/Cu2S/Pt structure with the Cu2S films annealed at 400°C, about 6 orders of magnitude higher than that for the memory unit with the Cu2S films deposited at room temperature.
KeywordsFilm growth Solid state electrolyte Switching property
This work was financially supported by the 863 project(2006AA03Z303) and the 973 project(2006CB921803).