A 3D model for simulating temperature and stress profiles during sub-millisecond laser spike annealing

We present a physical based model for simulating the temperature and stress fields that incorporate full temperature and rate dependent thermal, optical and mechanical properties scanned laser spike annealing. We simulate the system in a 2D infinite line beam limit and a full 3D model including spatial variation of the laser intensity. These simulations accurately model effects of the finite laser beam size. Temperature profiles for narrow beam widths (3D) exhibit shorter tails and steeper gradients as compared to the 2D model. The impact of beam profiles and spatial fluctuations (noise) on the temperature uniformity is presented. Direct experimental measurements of temperature-time profiles from a narrow beam spike annealing system are used to calibrate and validate these models. The simulated thermal profiles were used as inputs in a finite element simulator (COMSOL) to determine the thermally induced stress fields. Resolved shear stress slip systems were determined as a function of anneal conditions (dwell and peak temperature).