Laser-induced damage threshold of silicon under combined millisecond and nanosecond laser irradiation

The laser–silicon interaction process was investigated with the superposed radiation of two pulsed Nd:YAG lasers. A pulse duration of 1 millisecond (ms) was superposed by 7 nanosecond (ns) pulses, creating a combined pulse laser (CPL). The time-resolved surface temperature of silicon was measured by...

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Bibliographic Details
Published inJournal of applied physics Vol. 121; no. 11
Main Authors Lv, Xueming, Pan, Yunxiang, Jia, Zhichao, Li, Zewen, Zhang, Hongchao, Ni, Xiaowu
Format Journal Article
LanguageEnglish
Published Melville American Institute of Physics 21.03.2017
Subjects
Applied physics
Finite element method
Infrared radiation
Laser beam heating
Laser damage
Lasers
Mathematical models
Pulse duration
Radiation damage
Radiometry
Reflectance
Semiconductor lasers
Silicon
YAG lasers
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Summary:The laser–silicon interaction process was investigated with the superposed radiation of two pulsed Nd:YAG lasers. A pulse duration of 1 millisecond (ms) was superposed by 7 nanosecond (ns) pulses, creating a combined pulse laser (CPL). The time-resolved surface temperature of silicon was measured by an infrared radiation pyrometer. The melting thresholds of silicon were attained for a single ms laser and a CPL by infrared radiometry and time-resolved reflectance. The concept of threshold boundary was proposed, and a fitted curve of threshold boundary was obtained. An axisymmetric model was established for laser heating of silicon. The transient temperature fields were obtained for single ms laser and CPL irradiation using finite element analysis. The numerical results were validated experimentally, and an obvious decrease in melting threshold was found under CPL irradiation. That is attributed to pre-heating by the ms laser and the surface damage caused by the ns laser.
ISSN:0021-8979
1089-7550
DOI:10.1063/1.4978379