Chalcogenide Materials Fabrication and Initial Characterization for Reconfigurable Interconnect Technology

摘要

The optical properties of sputtered, amorphous films of GeTe, Sb2Te3, and Ge2SbTe5 grown up to several micrometers thick are influenced by the presence of oxygen impurities. The absorption edges in these glasses are sometimes broader than in standard chalcogenide glasses, such as GeSe2 and As2Se3. This result implies either that the valance band consists of high strained bonds or that large densities of defects exist. Below the optical gap the refractive index for Ge2Sb2Te5 is approximately 3.5. In samples of Ge2Sb2Te5 made with large oxygen concentrations using a hot-pressed target, there exists a large ESR signal corresponding to a defect density of 10 to the power of 19 cm to the power of -3. In samples with the lowest oxygen contamination levels (approximately 10 to the power of 19 cm to the power of - 3) no ESR signal is observed, which implies that the defect density is below 10 to the power of 18 com to the power of -3. ESR signals associated with the glassy SiO2 interface with the chalcogenide films are also observed. In amorphous Ge2Sb2Te5, the average coordination numbers for Ge, Sb, and Te are approximately 4, 3, and 2.5 respectively.