低能离子束诱导单晶硅点状纳米结构与光学性能研究

Nanodots Pattern and Optical Properties of Monocrystalline Silicon Induced by Low Energy Ion Beam

使用微波回旋共振离子源,研究了低能Ar+束在不同入射角度下对旋转单晶硅(100)表面的刻蚀效果及其光学性能。结果表明:样品旋转、离子束能量为1000eV、束流密度为265μA/cm2、刻蚀时间为60min时,在不同入射角度下,刻蚀后的样品表面可形成均匀的自组装点状结构。入射角度为0°～25°时,随着角度增加,样品表面粗糙度增大,点状结构有序性更强,光学透射率提高;继续增加入射角度,样品表面粗糙度及点状结构尺寸开始减小,光学透射率降低;增加入射角度到45$时,自组装点状结构消失,粗糙度和平均光学透射率达到最小值分别为0.83nm和55.05%;进一步增加入射角度,样品表面再次出现自组织装点状结构,表面粗糙度急剧增大,入射角度在65$时,平均光学透射率达到极大值64.59%;此后,随着离子束入射角度的增加,表面粗糙度缓慢减小,光学透射率降低。自组织结构变化是溅射粗糙化和表面弛豫机制相互作用的结果。

Electron cyclotron resonance （ECR） has been employed to etch the surface of monocrystalline silicon （100） with sample rotation, etching effects and optical properties of low energy Ar^＋ beams at different ion-beam incident angles are studied. The experimental results indicate that, when ion beam energy is 1000 eV, beam current density is 265 μA/cm2 , and etching time is 60 rain with simultaneous sample rotation, well ordered self-organized nanodot patterns form on the Si surface. Within 0°～25°, if the incident angle increases, root mean square （RMS） of the roughness and optical transmittance of the sample are enhanced with the growth of self-organizing nanostructure, when surface roughen functions principally. If the incident angle remains increaseing, the reducing size of self-organized nanodots lessen RMS and optical transmittance of samples. If the incident angle continues to increase nearly up to 45°, the dot patterns fade away, and RMS and mean optical transmittance of samples reach the minimums of 0.83 nm and 55.05 %, and the polishing effect is obvious for ion beams. If the incident angle further increases, the self-organized dot patterns appear on the sample surface again, RMS is dramatically enlarged and optical transmittance start to magnify with the angle increasing, and at about 65° , the mean optical transmittance get the maximum of 64.59 %, then the RMS and optical transmittance begin to decrease slowly with the incident angle increasing. The transformation self-organized nano-structure patterns results from the interaction of spurting roughness and relaxation mechanism.