Intrinsic Diffusion Coefficient of Interstitial Copper in Silicon

Transient ion drift experiments designed to obtain reliable values for the intrinsic copper diffusivity in silicon are reported. From these measurements, the diffusion barrier of Cu in Si is determined to be $0.18\pm 0.01\mathrm{eV}$. It is shown that the commonly used expression of Hall and Racette [J. Appl. Phys. 35, 379 (1964)] actually gives an effective diffusion coefficient for heavily boron-doped silicon and can neither be used for other doping levels nor extrapolated to lower temperatures. A model is developed which predicts the effective diffusion coefficient as a function of temperature, doping level, and the type of dopant.