In order to understand deeply the effect of background pressure on the laser ablation process and the plume expansion dynamics during the ns laser ablation of semiconductor, one dimensional laser ablation and fluid dynamics coupling model is utilized to simulate the ns laser ablation process of semiconductor Ge in an ambient gas He at different pressures. The results show that the pressure of ambient gas He influences a little on the laser energy incident on the target surface, and thus the target evaporation rate and the target surface temperature as well as the target ablation depth are insensitive to the variation of ambient pressure. Meanwhile, increasing the ambient pressure inhibits the plume expansion and reduces the plume expansion speed. The numerical results and analyses are beneficial to optimization of the ambient pressure during the ns laser ablation of semiconductors.
