A Computer Model for Pulsed Laser Heating of Device Structures

A rigorous, two‐region implicit Crank‐Nicolson finite difference solution of the heat diffusion equation for pulsed laser heating has been developed. The computer model includes the temperature, phase, and material dependences of the major optical and thermal properties. Melting is modeled by separating the heat equation into three distinct regions. The first corresponds to the solid phase, the third to the liquid phase, and the second to the situation where latent heat is being stored. The run time required for the most complex model situation is approximately 40 min c.p.u. time. The model is applied to a typical device structure which includes photoengraved thermally grown silicon dioxide with unimplanted and implanted windows. Good agreement is obtained in situations where experimentally measurable effects can be compared with model predictions, and the application of the model to laser annealing of oxide covered silicon is discussed with reference to parallel experimental studies.