A theoretical model of the femtosecond laser ablation of semiconductors considering inverse bremsstrahlung absorption

作     者：林晓辉 张赤斌 任维松 蒋书运 欧阳全会 

作者机构：School of Mechanical EngineeringSoutheast UniversityNanjing 211189China Wuhan Technical College of CommunicationWuhan 430062China 

出 版 物：《Journal of Semiconductors》 (半导体学报（英文版）)

年 卷 期：2012年第33卷第4期

页      面：144-148页

核心收录：

学科分类：080901[工学-物理电子学] 0809[工学-电子科学与技术（可授工学、理学学位）] 08[工学] 080401[工学-精密仪器及机械] 0804[工学-仪器科学与技术] 0803[工学-光学工程] 

主　　题：femtosecond laser nonequilibrium distribution inverse bremsstrahlung absorption ablation mecha-nism 

摘      要：The mechanism of the femtosecond laser ablation of semiconductors is investigated. The collision pro cess of free electrons in a conduction band is depicted by the test particle method, and a theoretical model of nonequilibrium electron transport on the femtosecond timescale is proposed based on the FokkerPlanck equa tion. This model considers the impact of inverse bremsstrahlung on the laser absorption coefficient, and gives the expressions of electron drift and diffusion coefficients in the presence of screened Coulomb potential. Numerical simulations are conducted to obtain the nonequilibrium distribution function of the electrons. The femtosecond laser ablation thresholds are then calculated accordingly, and the results are in good agreement with the experimental results. This is followed by a discussion on the impact of laser parameters on the ablation of semiconductors.