Millisecond laser-induced damage process of (001) silicon wafer

The damage process of (001) silicon wafer subjected to millisecond Gaussian laser irradiation is investigated. The laser pulse width is 1 ms, and the laser energy density ranges from 18 to 32 J / cm2. The damage mechanism is discussed by combining real-time experimental observation with numerical analysis based on a dislocation model. The first damage is dislocation multiplication, which is induced by the long irradiation time of a millisecond laser. The subsequent melting process begins at slip lines, not the spot center as is usually assumed. Fracture also occurs outside the spot center. Precise temperature in the cooling period cannot be obtained by simulation due to complicated dependence of thermal conductivity on dislocation, which may be the most urgent problem in further studies.