Study On Fabricating Of Silicon Nanostructure Based On Electric Field

Silicon(Si)nanostructures exhibit promising potential application in the semiconductor industry due to unique nano-scale effect and excellent physical properties.Various methods such as reactive iron etching,chemical etching and electrical chemical etching,have been used to fabricate Si nanostructures by now.Metal-assisted chemical etching has attracted increasing attention in recent years because it allows cost-efficient fabrication of Si nanostructures with high feature fidelity and high aspect ratio.The motion of noble metal particles is the key to fabricate Si nanostructures,but it is easily influenced by many variables,i.e.metal pattern and sort,oxidant concentration,crystal orientation and doping level of silicon.It is very difficult to efficiently control silicon nanostructure for the random and uncertain motion of noble metal.Thus,the concept of electric field is introduced in this paper based on the former literatures,to control the motion of noble metal particles by electric field according to the self-induced electric field model.The effect of controlling etching speed and direction is analyzed and fabrication method of silicon nanostructures based on electric field is developed.The main contents are as follows:(1)This paper introduces background and significance of research,application of Si nanostructures and fabrication method of silicon nanostructures.Summarize the research status and introduce the main contents of this paper.(2)The mechanism of MaCE and electrochemical etching method are analyzed.Controlling parameter is summarized in the manufacturing process.Electric field is introduced from the mechanism of MaCE and electrochemical etching method,and fabrication method of silicon nanostructures based on electric field is developed.(3)Experimental of MaCE based on electric field is carried out.The results demonstrate that method of MaCE has ability to control.The effect of the electric current density and controlling MaCE is studied.The boundary of effective field,the effect of electric current density and controlling MaCE and optimizations of the electric current density are obtained.(4)The mechanism of fabrication method of silicon nanostructures based on electric field is analyzed and electric field control model is introduced.To examine the ability of control etching direction using electric field,we design a experiment using two perpendicular electric fields.And the crystal orientation and Oxidant concentration are studied.The result demonstrates that Oxidant concentration can affect the electric field control model but the crystal orientation is not.(5)Explore the application of electric field control model and feasibility study of metal-assisted chemical etching of Si 3D nanostructure using direct-alternating electric field.Circular structure in silicon is fabricated by using circular field.The result of this experiment demonstrates that electric field control model has ability to fabricate 3D silicon nanostructures,and a novel solution is provided for preparing the silicon complex 3D nanostructures.