[The influence of laser plasma effects on the characteristics of silicon surface damage]

Silicon is the basic material for electro-photonic detectors, so the studies of the laser induced damage of silicon are of great significance in laser detecting and military applications. The damage characters of silicon under high intensity nanosecond laser pulses were investigated in the present paper. The results show that laser plasma has thermal effect, shock effect and spectral radiation effect, etc. These comprehensive effects combined together determinate the damage characters. By thermal effects and shock effects of laser plasma, the material is being melt, vaporized, ionized and pushed out at the laser irradiated area. In this way, the pit can be formed and the cooled ejected effluents are radially distributed. The silicon was melt at the bottom of the pit and the temperature was modulated by the intensity of the incident laser, which interfered with scattering laser simultaneously. The periodic heat distribution generates the period stripes. N, O and Si characteristic spectrum in the laser plasma prove that the colored film is the mixture of SiOx:SiNy which were sprayed out from laser plasma under repetitive laser pulses.