薄膜光学常数的模拟退火算法研究

Research on Stimulated Annealing Algorithm of Film Optical Constant

在薄膜的光学参数拟合时,操作者给定的模型初值对拟合结果有很大的关系。采用广泛用于求解复杂系统优化问题的模拟退火算法来求解薄膜光学常数,降低了操作者给定拟合模型初值的要求。通过对常规的模拟退火算法以及非常快速的模拟退火方法(Very Fast Stimulated Annealing,VFSA)分析,针对性地在模型扰动及退火计划上存在的缺陷作了改进,提高了 VFSA 算法的计算稳健性。通过大量的拟合实践,验证了提出的改进模拟退火方法的有效性。

The initial value given by the operator is very important for the measurement results of spectroscopic ellipsometry (SE) in the fitting of film optical constant, and the model requires the initial value with high standard. In the paper, the simulated annealing algorithm which is a new optimization method is widely used to determine the film optical constant in order to reduce the requirement of the initial value and make the operator obtain the accurate optical constant easily. Through the analysis of the stimulated annealing algorithm and very fast Stimulated Annealing (VFSA) method, it makes an improvement in the model disturbance and annealing scheme and also enhances the steadiness of VFSA algorithm. It proves the availability of the improved stimulated annealing method by using a large amount of fitting practice.