用PAA模板法实现硅基纳米孔阵列结构

Silicon nanopore array structure using porous anodic alumina

用二次阳极氧化方法制备出分立、双向贯通并且超薄(500—1000 nm)的多孔阳极氧化铝膜,贴合到硅片上进行干法刻蚀,实现图形转移,得到了硅基纳米孔阵列结构,并对工艺中影响图形转移质量的因素进行了探索.扫描电镜(SEM)测试结果表明该途径得到的纳米结构孔形态均匀且大面积有序,孔深度可达到125 nm.对该样品进行热氧化处理后进行光致发光(PL)测试,结果表明其光致发光机理是基于通常较微弱的TO声子辅助的硅带边发光,并实现了显著发光增强,对这种增强效果的物理机理进行了理论分析.该结构具有的独特光学特性为利用这一途径改变硅的弱发光性质,乃至实现硅基高效发光带来曙光.

A free-standing, bidirectionally permeable and ultra-thin （500--1000 nm） porous anodic alumina membrane was fabricated using a two-step aluminium anodization process, which was then placed on top of a silicon film as an etching mask. The pattern was transferred to silicon using dry-etching technology, and the silicon nanopore array structure was formed. The factors which affict the pattern transfer process are discussed. Observation of the nanopatterned sample under a scanning electron microscope shows that the structure obtained by this method is made up of uniform and highly ordered holes, which attains to 125 nm depth. The photoluminescence spectrum from the nanopatterned sample, the surface of which has been thermal-oxidized, shows that the the luminesce is evidently enhanced, the mechanism of which is based on the normally weak TO phonon assisted bandgap light- emission process, and the physical reasons that underlic the enhancement have been analyzed. The PL results do show an attractive optical characteristic, which provides a promising pathway to achieve efficient light emission from silicon.