1064 nm纳秒脉冲激光诱导硅表面微结构研究

利用Nd:YAG纳秒激光(波长为1064 nm)在不同气氛(空气、N₂,真空)中对单晶硅进行累积脉冲辐照,研究了表面微结构的演化情况.在激光辐照的初始阶段,与532和355 nm纳秒脉冲激光在硅表面诱导出波纹结构不同,1064 nm脉冲激光诱导出了微孔结构和折断线结构,并且硅的晶面取向不同,相应的折断线结构也不同.对于Si(111)面,两条折线交角为120°或60°,形成网状;而对于Si(100)面,两条折断线正交,从而将表面分成了15—20 μm的矩形块.结果表明,微孔结构的生长过程主要与相爆炸有关,而折断线的形成主要是热应力作用的结果.不同气氛对微结构形成的影响表明,刻蚀率和生长率与微结构的形成有密切的关系. 关键词： 纳秒激光 硅的微结构 相爆炸 热应力

Silicon surface microstructures created by 1064 nm Nd: YAG nanosecond laser

We investigated the evolution of surface microstructures created on single crystal silicon wafers by the cumulative Nd ∶YAG nanosecond laser pulses (wavelength 1064 nm ) in different atmospheres (N₂, air and vacuum). Micropore structure and the fracture lines are formed after irradiation of a few laser pulses,compared with ripple structures created by laser pulses of wavelengths of 532 and 355 nm. The fracture line structure is different for (111) and (100) silicon. The fracture lines have 60°and 120° intersections for (111) silicon. For (100)-oriented silicon wafers, two sets of fracture lines intersect at 90° to form a grid that divides the surface into rectangular blocks with side length of from 15 to 20 μm. We think that phase explosions are responsible for the growth of micropore structure. The fracture lines are mainly due to thermal stress. Finally, We studied the formation of microstructures under different atmospheres, and the results show that it is closely related to the etching and growth rate.