Study of lithium diffusion into silicon–germanium crystals

In this study lithium atoms were diffused into single crystal, Czochralski grown silicon–germanium. It is shown that the diffusion coefficient has a considerable dependence on germanium concentration. In addition the surface concentration of lithium in silicon–germanium is significantly higher than the values reported for float zone grown pure silicon crystals. The study compares direct and indirect characterization methods used to determine the lithium profile in silicon–germanium. The Si1−xGex semiconductors used in this study contain 2.6% and 5.4% (atomic concentration) of germanium and have measured resistivities of 100–200 Ω cm.