CN100477308C

CN100477308C - A making method for the diameter-adjustable silicon quanta line array

Info

Publication number: CN100477308C
Application number: CNB2007100404912A
Authority: CN
Inventors: 孙海彤; 李政皓; 陆明
Original assignee: Fudan University
Current assignee: Fudan University
Priority date: 2007-05-10
Filing date: 2007-05-10
Publication date: 2009-04-08
Anticipated expiration: 2027-05-10
Also published as: CN101055910A

Abstract

The invention pertains to the nanometer luminescent material preparation technology, specificly to a preparation method of a diameter adjustable silicon quantum wire array. Its step comprises using ion beam equipments to radiate on the silicon chip surface, generating a compact orderly silicon quantum sharing array, then evaporating aluminum electrodes in a vacuum vapor deposition system; in an electrochemical corrosion system, evaporating electrodes connected to the power supply, and ultimately generate silicon quantum wire array. The invention method is simple and convenient to carry out, the diameter of quantum wire array is controllable.

Description

The preparation method of the silicon quanta line array that a kind of diameter is adjustable

Technical field

The invention belongs to the nano luminescent material preparing technical field, be specially a kind of new method for preparing the adjustable silicon quanta line array of diameter.

Background technology

Quantum wire be meant the line cross-sectional diameter near or less than the solid straight line of a certain specific dimensions (being called Bohr radius), be also referred to as the quantum rod.Quantum wire has than with the bigger energy level energy gap of material blocks of solid, and diameter is more little, and energy gap is big more.Here it is so-called quantum limitation effect.Different materials has different Bohr radius.For example the Bohr radius of silicon is～5 nanometers.When quantum wire cross-sectional diameter during greater than Bohr radius～1-2 times, still have quantum limitation effect, be called weak restriction effect.When being equal to or less than Bohr radius, quantum wire has strong restriction effect.Utilize quantum limitation effect, not only can significantly strengthen the luminous intensity of solid material, can also regulate its emission wavelength.The main flow material of current microelectronic industry is a silicon.How realize photoelectronic integratedly on existing silicon technology basis, its key is to realize that silicon is luminous.But because silicon has the indirect band gap structure, its luminous efficiency is extremely low.Utilize nanometer technology, and, can improve the electronic structure of silicon, significantly promote its luminous intensity based on quantum limitation effect.

Silicon quanta line array has the strong characteristics of luminescence.Molecular beam evaporation and template are mainly adopted in the preparation of silicon quantum wire at present.The former silicon quantum wire density is little, arranges mixed and disorderly; And the latter is because process technology limit, and silicon quantum wire cross-sectional diameter minimum also has tens nanometers, is not real silicon quantum wire therefore.

Summary of the invention

The objective of the invention is to propose a kind of new method for preparing the adjustable silicon quanta line array of diameter.This method equipment needed thereby and technology are simple and easy to do, can below preparation cross-sectional diameter 10 nanometers on the silicon chip, silicon quanta line array that diameter dimension is controlled, intensive.

The method that on silicon chip, prepare silicon quanta line array that the present invention proposes, with ion beam irradiation at the fine and close orderly quantum dot array of silicon chip surface formation as template, combined with electrochemical corrosion means again.Concrete steps are as follows:

1) utilizes ar-ion beam equipment (as shown in Figure 1) that silicon chip surface is carried out radiation, generate fine and close orderly silicon quantum dot matrix.The quantum dot size can realize changing by regulating ion beam parameters, and final quantum dot controlled amount scope is that 1nm～70nm does not wait, and ion beam gets parameter, and mainly to utilize beam current density be 1 μ A/cm ²～800 μ A/cm ²Controlled.Generally can carry out 1-3 radiation by different beam current densities.The ion beam sputtering system of this step utilization routine can reach same effect.

2) silicon chip that surface (silicon chip front) is had the silicon quantum dot matrix is put into vacuum evaporation system, and at silicon chip back side AM aluminum metallization electrode, vacuum degree need be less than 2.0x10 ^-3Pa.

3) above silicon chip is put into electrochemical corrosion system (as shown in Figure 2), made the positive contact of silicon chip electrochemical corrosive liquid, evaporation has the back side of aluminium electrode to connect the electrode of power supply.Control etching condition such as electric current 1mA～100mA, etching time 1s～1hour, with final generation silicon quanta line array, its average diameter is by the silicon quantum dot diameter decision as template.This step also can be utilized other conventional electrochemical corrosion systems, reaches same effect.

Among the present invention, adopt argon ion normal incidence (perpendicular to silicon face) sample surfaces, make to produce the fine and close orderly silicon quantum dot array of self-organizing.

Among the present invention, silicon chip is a doped n type silicon.

Among the present invention, electrochemical corrosive liquid is the mixed liquor of hydrofluoric acid, ethanol and deionized water, and the hydrofluoric acid weight concentration is 1%-40%, and power supply for erosion is the pulse power.Etching tank is a polytetrafluoroethylene.Electrode is ringwise platinum filament in the corrosive liquid.

The principle of the invention is as follows:

1, the present invention utilizes the self-organized quantum dot technology of preparing that we develop, i.e. ion beam sputtering etching method forms fine and close sequential quantum dot matrix (M.Lu at silicon face, X.J.Yang, S.S.Perry, and J.W.Rabalais, Applied Physice Letters 80,2096-2098 (2002); Li Ling, Wei-qing Li, Le-jun Qi, Ming Lu, Xinju Yang, and Chang-xin Gu, Physical Review B71,155329 (2005); Wen-bin Fan, Le-jun Qi, Hai-tong Sun, You-yuan Zhao andMing Lu, Nanotechnology 17,1878-1883 (2006)).

2, we find that further formed silicon quantum dot matrix and silicon substrate have different electrology characteristics (Hai-Tong Sun, Zheng-Hao Li, Jing Zhou, You-Yuan Zhao and Ming Lu, Applied Surface Science in press, availableonline 18 January 2007), they have different electrochemical corrosion character thus.These silicon quantum dot matrix can be used as the template that produces the silicon quantum linear array.

3, according to hole principle (V.Lehmann, U.Goesele, Applied Physics Letters 58,856 (1991)), n type silicon is under the voltage reversal bias conditions, and the electrochemical corrosion speed that surface depressions is divided is much larger than other parts, and corrosion is longitudinal development.Combination principle 2 will form the silicon quantum linear array.

Description of drawings

Fig. 1 is for producing the equipment diagram of silicon quantum dot array.

Fig. 2 is electrochemical corrosion, promptly finally produces the equipment diagram of silicon quantum linear array.

Number in the figure: Fig. 1 is a five times regualting frame, and 2 is Faraday cup, and 3 is sample, 4 is ion gun, and 5 is the bias voltage heater, and 6 is Sample Room, 7 is turbomolecular pump, 8 is etching tank, and 9 is platinum wire, and 10 is screw, 11 are the good Si sample of preliminary treatment, 12 is contactor, and 13 is the pulse power of adjustable voltage, and 14 is etchant solution.

Embodiment

The ion beam apparatus that uses as shown in Figure 1, wherein, five times regualting frame 1 is by regulating sample 3 towards the angle and direction that changes ion beam incident; Faraday cup 2 is used to measure the size of incident ion bundle beam current density; The needs that two ion guns 4 adapt to different beam current densities respectively have been installed in the system, little line be the 04-303 of Perkin-Elmer company type ion gun, big line then be homemade common Kaufman ion gun; Bias voltage heater 5 is used to produce the beam bombardment sample back side of certain energy, the surface temperature when improving sample preparation; Each sample enters before the vacuum chamber, is introduced into Sample Room 6, and Sample Room is evacuated to rough vacuum, and then sample 3 is pushed on the specimen holder of vacuum chamber from Sample Room 6, goes out sample and is inverse process.Can reduce each sample introduction so to a great extent or go out the destruction of sample process ultra-high vacuum state in the vacuum chamber; Turbomolecular pump 7 makes that vacuum degree remains on 2.0 * 10 in the vacuum chamber ^-6Pa.If adopt tuftlet to wander about as a refugee son by force, then vacuum degree is 1.5 * 10 during sputter ^-5Pa is advisable; If adopt large beam ion to rob sputter, then vacuum degree is 2.5 * 10 ^-2Pa is advisable.

The electrochemical corrosion system adopts device shown in Figure 2.Its first half is a polytetrafluoroethylene etching tank 8, and the bottom has the corrosive liquid window, and base is a copper electrode, places sample above, is fixed by screw up and down.Platinum wire 9 is the electrode of etchant solution, and screw 10 is used for fixing etching tank 8 and copper electrode, so that the fixing sample of placing on the copper sheet.The Si sample 11 that preliminary treatment is good is placed on above the copper electrode of etching tank, contactor 12 control power supplys, and power supply adopts the pulse power 13 of adjustable voltage.

Further describe the present invention below by an embodiment.

1) successively utilizes H ₂O ₂: H ₂SO ₄=1: 1, ethanol and acetone soln clean the Si sheet.

2) n type Si (100) being put into the vacuum chamber of ion beam sputtering system, is 1.2-1.5keV with ion energy, and beam current density is 600-800 μ A/cm ²Argon ion vertically bombard the Si surface, form the Si quantum dot array, the some average diameter is～50nm.

3) be 0.5-1keV with ion energy further, beam current density is 15-30 μ A/cm ²Argon ion vertically bombard the Si surface, can modify some average diameter (Wen-bin Fan, the Le-jun Qi of Si quantum dot array, Hai-tong Sun, You-yuanZhao and Ming Lu, Nanotechnology 17,1878-1883 (2006)), make it less than 10nm.

4) this Si sheet is taken out the ion beam sputtering system, put into vacuum degree＜2.0x10 ^-3The deposition system of Pa is at its back side evaporating Al electrode.

5) the n type Si sheet that will plate the Al electrode and have a surperficial Si quantum dot array is put into the etching tank of etching system, corrodes, and etching condition is:

Electric current 10mA-30mA,

Time 5min-10min,

Etchant solution: HF (40% concentration): ethanol: H ₂O=1: 1: 2

The final Si quantum linear array that forms.

Claims

1, the preparation method of the adjustable silicon quanta line array of a kind of diameter is characterized in that concrete steps are as follows:

(1) utilizing ar-ion beam equipment that silicon chip surface is bombarded, generate fine and close orderly silicon quantum dot matrix, is 1.2-1.5keV with ion energy earlier, and ion beam current density is 600 μ A/cm ²～800 μ A/cm ²' hydrogen ion vertically bombard silicon face, form the silicon quantum dot array; The quantum dot array average diameter is 50nm; Be 0.5-1keV with ion energy again, ion beam current density is 15-30 μ A/cm ²Argon ion vertically bombard the Si surface, modify the some average diameter of Si quantum dot array, make it less than 10nm;

(2) silicon chip that the surface is had the silicon quantum dot matrix is put into vacuum evaporation system, and at silicon chip back side AM aluminum metallization electrode, vacuum degree need be less than 2.0x10 ^-3Pa;

(3) will put into the electrochemical corrosion system through the silicon chip of above-mentioned processing, make the positive contact of silicon chip electrochemical corrosive liquid, evaporation has the back side of aluminium electrode to connect the electrode of power supply, and the control etching condition is as follows: electric current 10mA～30mA, etching time 5 minutes～10 minutes finally generates silicon quanta line array.

2, preparation method according to claim 1 is characterized in that described electrochemical corrosive liquid is the mixed liquor of hydrofluoric acid, ethanol and deionized water, and the hydrofluoric acid weight concentration is 40%.