Real-Time Optical Quantification of Surface Diffusion in Semiconductor Nanostructures

We present an in-situ optical framework for precise quantification of high-temperature surface diffusion in silicon nanostructures under Joule heating. Silicon hole arrays are Joule-heated in high vacuum while real-time reflectance monitoring tracks pore shrinkage with sub-50 nm resolution. Surface temperature is measured via Raman thermometry, using Stokes peak shifts at moderate temperatures and Stokes/anti-Stokes intensity ratios at higher temperatures. Surface diffusion coefficients are extracted by fitting experimental diameter–time trajectories to phase-field simulations that explicitly incorporate curvature effects. The method circumvents exsitu imaging and simplified exponential fits, yielding validated, time-resolved diffusion coefficients for silicon under microfabrication-relevant conditions.