建立了一维半导体Ge激光烧蚀模型,对不同功率密度的紫外激光烧蚀半导体Ge的过程进行了模拟,并对计算结果进行了分析,得到激光功率密度对烧蚀过程以及蒸气膨胀动力学特性的影响。结果表明,激光功率密度的变化对烧蚀过程影响非常大。照射的激光功率密度越大,靶的表面温度越高,蒸发深度、烧蚀蒸气温度和膨胀的速度、相应蒸气膨胀的空间尺度也越大,且等离子体屏蔽现象出现得越早。在给定的烧蚀条件下,等离子体屏蔽的阈值在1×108～1.5×108 W/cm2之间。

One-dimensional dynamic semiconductor model was presented. The model has been used to investigate the influence of different laser power density on the laser ablation and the expansion of plume. The laser ablation is greatly influenced by laser power density. The more intensive the laser power density is, the higher surface temperature it would have. In this case, the depth of evaporation, the temperature of vapor, and the expansion velocity and spatial scale of ablated plume will also increase with the rising of laser power density. Meanwhile the more intensive the laser power density is, the earlier the plasma shielding would appear. For the given conditions, the threshold of plasma shielding value is between 1×108 W/cm2 and 1.5×108 W/cm2.