低能斜入射离子束诱导单晶硅纳米结构与光学性能研究

Microstructures and Optical Properties of Crystalline Si Surfaces Modified by Low Energy Ion Beam Erosion

为了研究低能Ar＋离子束在不同入射角度下对单晶硅表面的刻蚀效果及光学性能,使用微波回旋共振离子源,对单晶Si（100）表面进行刻蚀,采用原子力显微镜、非接触式表面测量仪和傅里叶变换红外光谱仪对刻蚀后硅片的表面形貌、粗糙度和光学透过率进行了测量。实验结果表明：当离子束能量为1000 eV、束流密度为265μA.cm-2、刻蚀时间为30 min时,离子束入射角度从0°增加到30°,样品表面出现条纹状结构。入射角度在0°~15°,随着角度增加,样品表面粗糙度增加,条纹周期减小,光学透过率提高;而在15°~30°范围内,随着角度增加,粗糙度开始减小,条纹周期增大,同时光学透过率降低。继续增加入射角度,条纹状结构逐渐消失,入射角度到45°时,粗糙度和光学透过率达到最小值;增加入射角度到55°,样品表面出现自组织点状结构,表面粗糙度急剧增大,光学透过率随着角度增加开始增加;继续增加离子束入射角度到80°,表面粗糙度和光学透过率继续增加,样品表面呈现出均匀有序的自组织柱状结构;此后,随着入射角度的增加,表面粗糙度又开始减小,光学透过率降低。自组织条纹结构到柱状结构的转变是溅射粗糙化和表面驰豫机制相互作用的结果。

The surfaces of the mono-crystalline Si（100） were modified by erosion of low energy microwave cyclotron resonance（ECR） Ar＋ beam.The microstructures and optical properties of the surface modified Si were characterized with atomic force microscopy,Fourier transform infrared（FT-IR） spectroscopy,and conventional optical proves.The impacts of Ar ion beam erosion conditions,including the beam energy and current density,incident angle,and erosion time,on surface morphologies were evaluated.The preliminary results show that at 1000 eV,a current density of 265 μA·cm-2,and for an erosion time of 30 min,the incident angle strongly affects the surface roughness,shape of the self-assembled nano-ripple,and optical transmittance.For example,as the incident angle increased from 0° to 15°,the surfaces roughened,the period of the nano-ripples decreased,and the transmittance increased.However,as the incident angle increased from 15° to 30°,the surface roughness decreased,the period increased,and the transmittance decreased.Possible mechanisms were also tentatively discussed.