In laser processing, due to the short interaction time between an ultrashort pulse laser and silicon, it has been difficult to study the lattice temperature change characteristics of silicon. In this paper, the interaction between a picosecond laser and silicon was studied. Based on the Fokker-Planck equation and two-temperature model (TTM) equation, a simulation model of silicon heating by different pulse-width picosecond lasers was established. The results show that within the range of 15 to 5 ps, the maximum lattice temperature tended to increase first and then decrease with the decreasing pulse width. The watershed was around 7.5 ps. The model error was less than 3.2% when the pulse width was 15 ps and the single pulse energy was 25 μJ.
Keywords: lattice temperature; picosecond laser; pulse width; silicon.