Model for Solute Diffusion in Crystals with the Diamond Structure

Abstract

A theory for solutediffusion in crystals with the diamondstructure such as germanium and silicon is derived by considering the effect of impurity ion size difference and also the coulombic interaction between impurity ions and charged vacancies. The theory is compared with experimental results reported for germanium and silicon and the agreement is considered quite good. The experimental observations that n‐type impurities diffuse considerably faster than p‐type impurities in germanium, whereas the opposite effect is observed in silicon, are explained by the theory. Because of the relation between the Fermi energy and vacancy acceptor level, the coulombic interaction is shown to be the predominating factor in germanium, whereas in silicon the size difference between impurity ions is shown to predominate.