Measurement of silicon interstitial diffusivity

A conceptually simple experiment to measure silicon interstitial diffusivity is described. The structure uses a silicon wafer with buried layers deep in the bulk. Oxidation of the wafer surface generates interstitials that diffuse into the wafer and enhance the buried layer diffusion. The results show that the interstitial profiles are flat out to 40 μm for the times and temperatures investigated. We can thus conclude that the interstitials move significantly faster than previously thought.