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Method for preparing silicon-based nano-scale ordered porous silicon

A nano-sized, porous silicon technology, applied in the field of silicon-based porous silicon, can solve the problem that porous silicon cannot satisfy high specific surface area and highly ordered pores at the same time, and achieve excellent performance, highly ordered pores, and large specific surface area Effect

Inactive Publication Date: 2013-03-06
TIANJIN UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0005] The purpose of the present invention is to overcome the disadvantages that the porous silicon in the prior art cannot simultaneously satisfy the high specific surface area and highly ordered pores, and to provide a porous silicon material with simple operation, low cost, mature technology, and flexible adjustment of the shape of the pores and the size of the pores. Preparation method of silicon-based nano-sized ordered porous silicon

Method used

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  • Method for preparing silicon-based nano-scale ordered porous silicon
  • Method for preparing silicon-based nano-scale ordered porous silicon
  • Method for preparing silicon-based nano-scale ordered porous silicon

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Embodiment 1

[0027] (1) Wafer cleaning:

[0028] An n-type (100) single-sided polished single-crystal silicon wafer with a resistivity of 0.015Ω·cm and a thickness of 400±10μm is cut into a rectangular silicon substrate with a size of 2.2cm×0.8cm, and put into acetone solvent in turn, Ultrasonic cleaning in absolute ethanol and deionized water for 20 minutes respectively, followed by soaking in 5% hydrofluoric acid aqueous solution for 15 minutes, and then washing with deionized water for later use.

[0029] (2) Preparation of silicon-based porous silicon:

[0030] A porous silicon layer was prepared on the polished surface of a silicon wafer by a double-groove electrochemical etching method. Firstly, the hydrofluoric acid aqueous solution with a mass fraction of 7% is added into the electrochemical corrosion tank as a corrosion solution, without adding surfactants and oxidants; then a pair of platinum metal electrodes are respectively inserted into the two half tanks as cathode and anode...

Embodiment 2

[0033] This embodiment is similar to Embodiment 1, except that the corrosion solution used in step (2) is a hydrofluoric acid aqueous solution with a mass fraction of 6%, and the applied corrosion current density is 120mA / cm 2 , the corrosion time is 20min. The scanning electron microscope photos of the prepared silicon-based porous silicon surface morphology and cross-sectional structure are as follows: Figure 4 and Figure 5 shown. The average pore diameter of the prepared porous silicon parameters is 227.81nm, the layer thickness is 33.39μm, and the porosity is 66%. The hole wall is relatively smooth.

Embodiment 3

[0035] This embodiment is similar to Embodiment 1, except that the corrosion solution used in step (2) is a hydrofluoric acid aqueous solution with a mass fraction of 7%, and the applied corrosion current density is 125mA / cm 2 , the corrosion time is 15min. The scanning electron microscope photos of the prepared silicon-based porous silicon surface morphology and cross-sectional structure are as follows: Figure 6 and Figure 7 As shown, the average pore diameter of the prepared porous silicon parameters is 112.25nm, the layer thickness is 53.42μm, the porosity is 68.75%, the surface morphology is a honeycomb structure composed of polygonal pores, and the cross-sectional morphology is straight cylindrical. sequence, the walls of the pores are very rough and side pores appear.

[0036] In the present invention, the method of weighing samples with an electronic balance is adopted, and the porosity and thickness of silicon-based porous silicon are obtained through formula calcu...

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Abstract

The invention discloses a method for preparing silicon-based nano-scale ordered porous silicon, comprising the following steps of: (1) ultrasonically washing an n-shaped one-side polished monocrystalline silicon piece in an acetone solvent, absolute ethyl alcohol and de-ionized water sequentially; and (2) preparing a porous silicon layer on the polished surface of the silicon piece by a double-tank electrochemical corrosion method, taking the aqueous solution of hydrofluoric acid having the mass fraction of 5-9% as corrosive liquid, and applying corrosion current, wherein the density of the corrosion current is 75-155 mA / cm<2>, and the corrosion time is 5-30 min; and the process is performed at the room temperature without illumination. The method disclosed by the invention is simple, quick, effective and practicable, and high in operability; and the bore diameter of the obtained porous silicon is at hundred-nanometer scale, and has the characteristics of high porosity and highly ordered pore canals. The method is capable of achieving the purpose of the silicon-based nano-scale ordered porous silicon by controlling the concentration of the hydrofluoric acid, the corrosion current density and the corrosion time; and the silicon-based nano-scale ordered porous silicon is an ideal material for preparing biological and chemical sensor elements.

Description

technical field [0001] The invention relates to silicon-based porous silicon, in particular to a method for preparing silicon-based nanometer-sized ordered porous silicon by means of a double-groove electrochemical corrosion method. Background technique [0002] Porous silicon was first discovered by Uhlir in 1956 during electrochemical polishing in hydrofluoric acid aqueous solution. Silicon-based porous silicon is formed by etching on the surface of silicon wafers. Although it is still composed of silicon atoms, it exhibits many physical and chemical properties different from single crystal silicon materials due to its special porous microstructure. For example, use the photoluminescent properties of porous silicon to manufacture optoelectronic devices; use the low thermal conductivity of porous silicon to prepare heat-insulating layer materials; use the characteristics of large specific surface area and high surface chemical activity of porous silicon to prepare low-power...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C25F3/12C25F3/14
Inventor 胡明李明达刘青林闫文君马双云
Owner TIANJIN UNIV
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