Solubility of Lithium in Doped and Undoped Silicon, Evidence for Compound Formation

The solubility of lithium in silicon from a lithium-silicon alloy phase has been redetermined. The original data of Fuller and Ditzenberger appear to be in error. The solubility of lithium, from the same phase, in boron-doped silicon has also been determined. At both low and high temperatures the solubility in the doped crystal markedly exceeds that in the undoped one. In fact, the solubility just about equals the boron concentration in these ranges. The low temperature disparity can be explained in terms of hole-electron equilibria while the high temperature effect is believed due to covalent bond formation between lithium and boron. A quantitative theory is developed which predicts the experimental results.