Study On Fabricatiing Non-destructive Structurs On Monocrystaline Silicon Surface By Localized Oxide Mask-induced Selective Etching

Monocrystalline silicon has excellent mechanical,physical and chemical properties,and becomes an important material for fabricating solar cells,large-scale integrated circuits and semiconductor-related devices.At present,nanofabrication technology has developed rapidly,and nanoimprint technology,lithography technology and focused ion beam technology have emerged,which are widely used in biomedicine,aerospace and MEMS.Nanotechnology nowadays infiltrates into people's lives and production process in all aspects,bringing out the diversity of nanotechnology,and it is inevitable to develope new nanofabrication technology methods.The nanofabrication technology based on probe scanning can fabricate various patterns on the monocrystalline silicon surface by controlling the path of tip movement.It not only has the advantages of fast and efficient,but also can realize site-controlled fabrication.Local anodic oxidation is one of the important applications of probe-based scanning nanofabrication.With this method,a positioning mask is fabricated on the monocrystalline silicon surface,and combined with subsequent selective etching,which is expected to fabricate the non-destructive micro/nano structures.In this paper,atomic force microscope(AFM)was used to investigate nanofabrication process based on oxide mask-induced selective etching,and the influence of fabricating parameters on the formation of nanostructures on the monocrystalline silicon surface was studied.The damage characteristics of nanostructure was studied by using conductive atomic force microscope(CAFM)to measure the conductivity of fabricated nanostructure and high-resolution transmission electron microscope(HRTEM)was adopted to measure cross section of the nanostructure.Finally,non-destructive fabricating was carried out on the gallium arsenide surface to further explore the application of this method.The specific research contents were as follows.(1)The effect of fabricating parameters on oxide mask-induced selective etching on monocrystalline silicon surface was investigatedThe natural oxide film on the surface of monocrystalline silicon was not conducive to the formation of a high-quality anodic mask.Before the fabricating experiment,the surface of monocrystalline silicon was treated with hydrofluoric acid(HF)solution to remove the natural oxide film to ensure the consistency of the surface of the sample.The effects of anodic scanning speed and selective etching time on the height of the fabricated structure were investigated.The optimum fabricating conditions were determined.The scanning speed was 1.2-16 ?m/s and selective etching time was no more than 8 minutes.The comparative experiments on different monocrystalline silicon surfaces showed that the Si(100)surface was the most suitable for oxide mask-induced selective etching.(2)The damage of the fabricated nanostructure was studiedCAFM was used to detect the conductivity of the fabricated nanostructure.The surface conductivity was not significantly different from that of silicon substrate.It could be inferred that there was no obvious damage inside.In order to further verify the damage characteristics,the cross section of fabricated nanostructure was observed by HRTEM,and the crystal lattice arrangement was almost perfect.Therefore,the structures fabricated by oxide mask-induced selective etching were non-destructive.(3)Non-destructive structure fabricating based on oxide mask-induced selective etchingA series of nanostructure patterns were fabricated on HF-treated silicon surface by localized oxide mask-induced selective etching by using closed-loop fabricating of AFM.At the same time,a series of groove structures could also be fabricated with the similar method on the gallium arsenide surface by local anodic oxidation-subsequent etching(etching in dilute hydrochloric acid).After the damage detection of CAFM,it was found that the fabricated array structures were also non-destructive.Non-destructive structure fabricating of monocrystalline silicon and gallium arsenide surface can be realized by the oxide mask-induced selective etching method,and the fabricating method is simple,flexible,and low in cost.In this paper,the fabricated rule of oxide mask-induced selective etching is studied.CAFM and HRTEM are used to analyze the damage characteristics of the fabricated structures.Related research is expected to further enrich the nanofabrication system based on probe scanning technology.