Selective Deposition Process Of Nano/microstructures On Homogeneous Substrates Modulated By Surface States Of Semiconductors

Micro-nano fabrication technologies are instrumental technologies,which are used to serve scientific researches and the development of industrial products.Micro-nano fabrication technologies are also developing technologies.New research projects and development of industrial products will constantly put forward new requirements for micro-nano fabrication technologies.Micro-nano devices have been widely applied in fields such as sensing,energy,communication and medical.Selective deposition technologies could achieve self-aligned deposition of micro-nano structures without physical masks,reducing the difficulty for the fabrication of micro-nano structures.On the other hand,the development of 3D micro-nano devices also put forward urgent requirements for selective deposition technologies.However,the top-down micro/nano fabrication technologies represented by photolithography lack the ability of selective deposition especially on 3D homogeneous substrate.In order to provide brand-new ideas and theories for the design and application of selective deposition technologies,this thesis"selective deposition process of nano/microstructures on homogeneous substrates modulated by surface states of semiconductors"has carried out the theoretical analysis and coreesponding experimental research.The main research contents of this thesis include:1.The regulation mechanism of high-density surface states on electrochemical behaviors of semiconductors is revealed.Analysis based on the density functional theory and characterizations of scanning transmission microscope and atomic force microscope are carried out to qualitatively research the surface atom arrangement and energy level position of surface states on defective regions.Ultraviolet photoelectron spectroscopy analysis and electrochemical impedance tests are carried out to quantificationally obtain the density and energy level distribution of introduced surface states of n-type silicon with（100）orientation.Combining above data and semiconductor electrochemical theory,the regulation mechanism of high-density surface states on electrochemical behaviors of semiconductors is revealed.And the mechanism is verified by the localized current-bias response results tested by scanning electrochemical microscope.2.Based on the regulation mechanism of high-density surface states on electrochemical behaviors of semiconductors,a selective deposition process modulated by surface states is developed.This process could achieve selective deposition of a variety of materials on homogeneous semiconductor substrates.Respective characteristics and suitable deposition materials of cathodic deposition mode,anodic deposition mode and electroless deposition mode are verified on planar n-type silicon substrate with（100）orientation.The selectivity of deposition,processing resolution and processing size range of the fabricated micro/nano structures are characterized by scanning electron microscopy,atomic force microscopy and energy spectrum.3.The selective deposition of Cu₂O layer and CoO_x layer respectively on the side wall and the top of silicon micropillar array verifies the 3D processing capability of the selective deposition process modulated by surface states.The selective deposition of Cu₂O on the side wall of silicon micropillar array by cathodic deposition mode and selective deposition CoO_x on the top of silicon micropillar array by anodic deposition mode are controllable and sequentially adjustable.The strict selectivity of corresponding deposition regions is characterized by scanning electron microscopy and energy spectrum analysis.Meanwhile,the results of photoelectrochemical tests reveal that this 3D composite structure has excellent photoelectrochemical properties,which further proves the 3D processing capability of the selective deposition process modulated by surface states.