激光与光电子学进展, 2011, 48 (3): 031201, 网络出版: 2011-01-18
类金刚石薄膜光学参数反演的改进遗传算法
Improved Genetic Algorithm Inverted with Optical Constants of Diamond-Like Carbon Film
薄膜 类金刚石(DLC)薄膜 光学常数 改进遗传算法 椭偏数据反演 films diamond-like carbon optical constants improved genetic algorithm ellipsometric data inversion
摘要
椭偏法测试薄膜不能直接得到薄膜的光学参数,需进行数值反演算法近似求解。采用遗传算法,借鉴竞争选择、小生境和适应值调节思想,对选择算子、变异算子、交叉算子三个重要算子进行了适当改进,改进后算法有效防止了“早熟”现象,并搜索到了全局最优,降低了操作者对拟合模型设定初值的要求。在实践上,通过3种拟合方式的结果对比,得到了可靠的某条件下制备的类金刚石薄膜的光学常数,验证了改进遗传算法在拟合薄膜光学常数中的有效性。
Abstract
Ellipsometry can not be directly tested by thin film optical parameters, which needs approximate solution method for numerical inversion. Using genetic algorithms, the selection operator, mutation operator and crossover operator are improved by drawing from competition, selection and fitness niche adjustment idea. The improved algorithm is effective in preventing the "premature" phenomenon. It searches the global optimal and reduces the requirements on the operator to set the initial value on the fitted model. In practice, by comparing the results of the three fitting methods, we gain reliable optical constants of diamond-like carbon (DLC) films prepared under certain conditions. The improved genetic algorithm is effective to fit thin film optical constants through a large number of fitting.
李建超, 苏俊宏, 徐均琪. 类金刚石薄膜光学参数反演的改进遗传算法[J]. 激光与光电子学进展, 2011, 48(3): 031201. Li Jianchao, Su Junhong, Xu Junqi. Improved Genetic Algorithm Inverted with Optical Constants of Diamond-Like Carbon Film[J]. Laser & Optoelectronics Progress, 2011, 48(3): 031201.