CN1037727C - Etching liquid for etching porous silion, etching process use same and method making semiconductor substrate for such etching liquid - Google Patents
Etching liquid for etching porous silion, etching process use same and method making semiconductor substrate for such etching liquid Download PDFInfo
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Abstract
A method for preparing a semiconductor member comprises: forming a substrate having a non-porous silicon monocrystalline layer and a porous silicon layer; bonding another substrate having a surface made of an insulating material to the surface of the monocrystalline layer; and etching to remove the porous silicon layer by immersing in an etching solution.
Description
The caustic solution that the invention relates to porous silicon etching solution and use this corrosive liquid, more particularly, be about the corrosive liquid of selective corrosion porous silicon from substrate and from the substrate the method for selective corrosion porous silicon.
As silicon on insulator (SOI) technology, it is well-known forming the monocrystalline silicon semiconductor layer on insulator.Because inaccessible all superiority when adopting the device of this SOI technology to have to adopt the body silicon substrate to make common silicon integrated circuit are so obtained many successful researchs.In other words, utilize the SOI technology can obtain following these advantages:
1. because of being easy to realize dielectric isolation, can improve integrated level;
2. have superior radio resistance property;
3. stray capacitance is low, can realize high-speed;
4. can save trap and form operation;
5. can prevent latch-up (Batoh up);
6. can make the complete depletion type transistor with thin-film technique.
For realize above-mentioned these in the advantage aspect the device property, studying the method that forms soi structure nearly recent decades always.The content of this respect has summary introduction in disquisition " monocrystalline silicon on the on-monocrystalline insulator " (G.W.Cutten writes, Journal of CrystalCrowth, vol.63, no.3.1983 pp429-590).
People just know that CVD (chemical vapor deposition) method with silicon carrying out heteroepitaxy to form epitaxial silicon on the so-called sapphire (SOS) on the monocrystalline sapphire substrate for a long time.Though obtained preliminary success as the most ripe SOI technology, but owing to the lattice at the interface of silicon layer and following Sapphire Substrate matches a large amount of crystal defects does not take place, this causes because of there being the aluminium Sapphire Substrate to sneak into to silicon layer, and, hinder its extensive use more because substrate costs an arm and a leg and large tracts of landization is slow always.In recent years, carried out realizing not using the trial of the soi structure of Sapphire Substrate.The effort of this respect can roughly be divided into following two classes:
(1) hole of windowing after monocrystalline substrate is made surperficial oxidation processes reveals the part silicon chip, with this part as seed crystal towards laterally carrying out epitaxial growth, thereby at silica (SiO
2) form monocrystalline silicon layer (, producing silicon deposit on the oxidation silicon face simultaneously) on the face in such cases;
(2) with monocrystalline substrate itself as active layer, form silica (adopt this method, the silicon layer deposit can not take place) in its underpart;
As the means that realize above-mentioned (1), known having now: by CVD technology, the method for transversal epitaxial growth monocrystalline silicon directly; Deposition of amorphous silicon utilizes heat treatment to carry out the solid phase transversal epitaxial growth method; Electron beam, laser homenergic bundle are focused on, amorphous or polysilicon layer are shone, rely on melting recrystallization to make the method for growing single-crystal silicon layer on the oxidation silicon face; And utilize heater air flow pressure switch rod to make banded melting zone scan method (zone melting recrystallization).Though above-mentioned these methods each have its pluses and minuses, remain in problems aspect, production efficiency controlled, uniformity, the quality, thereby also do not reach industrial realistic scale at it.Such as when adopting the CVD method, film is smooth will inevitably to bring some sacrifices because of oxidation processes in order to make; And in the solid state growth method, its crystal property is bad.In addition, in the energy beam annealing method, then, need have the length in processing time, the problem that energy beam overlapping conditions and focus adjustment etc. are controlled because of carrying out the energy beam focusing scanning.Wherein,, and just carrying out the fairly large burnt trial production that becomes circuit,, and can't form minority carrier devices still owing to there is crystal defect such as effective crystal boundary mostly though zone-melting crystallization method is the most ripe.
In the said method (2),, be listed below several without the method for silicon substrate as epitaxially grown seed crystal:
1. anisotropically corrode from the teeth outwards on the monocrystalline substrate of forming V-shape ditch and form oxide-film, the polysilicon layer of deposit and silicon substrate same thickness on this oxide-film, grind from the back side of silicon substrate then, be formed on the thick polysilicon layer by the V-arrangement ditch the cingens monocrystalline silicon region of being opened by dielectric isolation.This practice, though excellent in crystallinity, carry out in the operation of the hundreds of micron thickness polysilicons of deposit and to monocrystalline substrate grinding back surface only keep exist controlled in the operation of the silicon active layer of keeping apart and production efficiency aspect etc. problem.
2. being referred to as the partition method (SIMOX-Separation byion implanted oxygen) that ion injects oxygen is that dependence is injected the method that monocrystalline substrate forms silicon oxide layer with oxonium ion, becomes the most ripe current means because its silicon is handled and matching is good.But, must inject 10 because will form silicon oxide layer this moment
13Ions/cm
2Above oxonium ion, injection length is very long, be difficult to enhance productivity, and the wafer cost is very high.In addition, residual have a lot of crystal defects, sees with industrial viewpoint, do not reach the quality that can make minority carrier devices fully as yet.
3. by carrying out the method that dielectric isolation forms soi structure with the porous silicon oxidation processes.This method is to utilize on the p type single crystal silicon substrate surface (to see modern well etc. with proton ion injection N type silicon layer, J.Crystal Growth, Vol.63,1983, p547), perhaps by epitaxial growth be carved into figure and make island, surround this silicon island by the surface, anodization process is carried out in utilization in HF solution, only make P type silicon substrate porous, by the speedup oxidation dielectric isolation is made in N type silicon island then.When adopting this method, segregate silicon area was determined before the device operation, thereby is existed the problem of limiting device design freedom aspect.
Therefore, light-transmissive substrates is significant for the contact pickup and the projection-type liquid crystal image display apparatus aspect that constitute as light-sensitive element.Yet, when the PEL (picture element) density that will further improve transducer and display unit, resolution and definition, the fabulous driving element of performance just must be arranged.Therefore, also just must adopt the good single crystalline layer of crystal property to realize as the element that is set on the light-transmissive substrates.
But the common randomness of its crystalline texture of reflection on the light-transmissive substrates of similar glass and so on even deposit silicon layer only also can only form and noncrystal, betterly also can only form polycrystal layer, can not make high performance device.Like this because the substrate crystal structure is amorphous, even thereby deposit silicon layer only, also can not get the single crystalline layer of high-quality.Because amorphous silicon and polysilicon are the crystal structures with many these class defectives, realize that driving element current or needed enough performances from now on is difficult.
And, on light-transmissive substrates, realize the high-quality single crystalline layer no matter adopt any method of above-mentioned single crystalline substrate all to be unwell to.
One of the present inventor Mi Yuanlong husband is for solving the problem of above-mentioned existence, be willing to disclose in the flat 2-206548 application case a kind of method invention that forms semiconductor chip the spy, it is characterized in that: in the formation method of this semiconductor chip, form earlier the substrate of the semiconductor layer of semiconductor single crystal layer with non-porous matter and porous matter, surface with this single crystalline layer combines with the substrate with insulating material surface then, relends and helps corrosion that porous semiconductor layer is removed.
The present invention proposes for the scheme of further improving the special flat 2-206548 of hope.Be willing in the flat 2-206548 number application the spy, illustrated and comprise and utilize corrosion process selectively to remove the Semiconductor substrate formation method of the operation of porous silicon.Below porous silicon is illustrated.
Porous silicon be Uhlir equal in the research process of semiconductor being made electrolytic polishing, to find in 1956 (see A.Uhlir, Bell Syst.Tech.J.Vol.35,1956, p333).
In addition, the fusion reaction of the silicon in people's antianode process such as Unagami is studied; In the anode reaction of silicon, the hole is necessary in HF solution, to being reported as follows of this reaction (see J.Electrochem.Soc.Vol.127,1980, p476):
Therefore as can be known, in the time will making porous silicon the hole must be arranged, and compare with N type silicon, P type silicon becomes porous silicon easily.But, if to N type silicon injected hole, also can become porous silicon and (see R.P.Holmstrom ﹠amp; J.Y.Chi, Appl.Phys Lett, Vol.42, p386,1983).
With monocrystalline silicon density 2.33g/cm
3Compare, when the HF solution concentration was changed in the 50-20% scope, the density of this porous silicon layer can be at 1.1-0.6g/cm
3Change in the scope.As observing, can find that this porous silicon layer is formed with the aperture of the about 600_ of average diameter by perspective electron microscope.Although this density still is half that monocrystalline silicon is compared, also keeping the character of monocrystalline, still might be at porous layer upper epitaxial growing single-crystal silicon layer.
Generally, monocrystalline silicon is once oxidation processes, and its volume will increase to about 2.2 times, but relies on the measure of control porous control porous silicon density, just might suppress this volumetric expansion, thereby can avoid the bending of substrate and cause breaking of remained on surface single crystalline layer.Volume after the oxidation is represented such as following formula the porous silicon volume of monocrystalline silicon:
R=2.2 * (A/2.33) wherein, A is the density of porous silicon.If R=1, promptly volume does not increase after the oxidation, then A=1.06 (g/cm
3).That is to say,, just can suppress the volumetric expansion that causes owing to oxidation if the density of porous silicon layer is 1.06.
We can say that now porous silicon is wanted directly the operation (epitaxial growth and oxidation) through subsequently after creating, but porous silicon itself is not processed, the original appearance after also keeping being made into.Its reason is that the control ability that is difficult to good processes porous silicon, or removes it.Promptly, the relevant example that porous silicon is corroded of accurately controlling does not have report as yet yet.
In addition, generally represent with following formula as the P of porosity (Porosity):
P=(2.33-A)/2.33 (7) adjusts this value when anodization in the scope of 30-55%, can make the oxidized porous silicon with monocrystalline silicon oxide-film equal quality thus, and porosity can be represented as
P=(m1-m2)/(m1-m3) (8) or
In P=(m1-m2)/ρ At (9) formula
M1 is the gross weight before the anodization
M2 is the gross weight after the anodization
M3 is the gross weight of removing behind the porous silicon
ρ is the density of monocrystalline silicon
A is the area in porous zone
T is the thickness of porous silicon but as a rule, can't correctly calculates the area in porous zone.At this moment, though formula (8) is effective, in order to measure m3, the corrosion of porous silicon of just having to.
When doing epitaxial growth on above-mentioned porous silicon, porous silicon is owing to the character of its structure, and the distortion that has taken place when having reduced heteroepitaxial growth promptly may suppress the generation of defective.But in this case, the porosity of porous silicon obviously is a very important parameter.Therefore, above-mentioned measurement method of porosity also is absolutely necessary in the case.
Known the having now of the caustic solution of porous silicon:
(1) with NaOH aqueous corrosion porous silicon method (G.Bonchil, R.Herino, K.Barla, and J.C.Pfister, J.Electrochem.Soc., Vol, 130, no.7 1983, p1611).
(2) usefulness can be used for the method for the corrosive liquid corrosion of porous silicon of non-porous silicon corrosion.
Usually adopt the corrosive liquid of fluorine nitric acid system in the said method (2), this moment, the corrosion process of silicon was shown below:
In the caustic solution of non-porous silicon, except that being the corrosive liquid, also has ethylenediamine system, KOH system and hydrazine system etc. with above-mentioned fluorine nitric acid.
Here, in order to carry out porous silicon selective corrosion, except the corrosive liquid that above-mentioned these non-porous silicons are used, also must select the corrosive liquid of other energy corrosion of porous silicon.In the porous silicon selective corrosion of carrying out before, have in the said method (1) with the method for the NaOH aqueous solution as corrosive liquid.
As mentioned above, porous silicon and non-porous silicon all are subjected to the corrosion that fluorine nitric acid is corrosive liquid.
In addition, in the selective corrosion method of the porous silicon of the employing NaOH aqueous solution that has carried out, the Na ion inevitably can be attached on the surface that is corroded.These Na ions then become the main source of contaminating impurity, and are movable.This can only cause baneful influences such as producing interface energy level, introduces unnecessary material in semiconductor technology.
One object of the present invention is, provide not to semiconductor technology bring harmful effect, do not corrode non-porous silicon, and can high efficiency, the corrosive liquid that equably porous silicon corroded.
Another object of the present invention is to provide the corrosive liquid of the present invention method of corrosion of porous silicon selectively of utilizing.
Above-mentioned purpose of the present invention can by of the present invention from the substrate the corrosive liquid of selective corrosion porous silicon realize, wherein, described substrate is made of porous silicon and non-porous silicon, it is characterized in that this corrosive liquid comprises one by hydrofluoric acid and a kind of solution of forming in ethanol and the hydrogen peroxide at least, or hydrofluoric acid of handling by buffer and a kind of solution of forming in alcohol and the hydrogen peroxide at least.
Caustic solution of the present invention utilizes above-mentioned corrosive liquid of the present invention to come the substrate that is made of porous silicon and non-porous silicon is carried out selectable corrosion of porous silicon exactly.
Adopt the corrosive liquid of corrosion of porous silicon of the present invention can be evenly and corrosion of porous silicon expeditiously, pollute and can not produce to semiconductor technology.
And caustic solution of the present invention can be applicable to common semiconductor technology, and owing to use the corrosive liquid do not corrode non-porous silicon, thus can be very accurately and selectively corrosion remove be set at the same substrate of non-porous silicon on porous silicon.
To brief description of drawings:
Figure 1A-1B is the schematic diagram that the corrosion process of corrosive liquid of the present invention is used in explanation;
Fig. 2 A-2B is the schematic diagram that the corrosion process of corrosive liquid of the present invention is used in explanation;
Fig. 3 A-3C is the schematic diagram that the corrosion process of corrosive liquid of the present invention is used in explanation;
Fig. 4 A-4C is the schematic diagram that the corrosion process of corrosive liquid of the present invention is used in explanation;
Fig. 5 A-5D is the schematic diagram that the corrosion process of corrosive liquid of the present invention is used in explanation;
Fig. 6 A-6H is that the etching characteristic figure of porous silicon and non-porous silicon is used under the situation of corrosive liquid of the present invention in explanation;
Fig. 7 A-7H be explanation when using corrosive liquid of the present invention and carrying out the porous silicon corrosion the porous silicon thickness that is corroded and the graph of a relation between the time.
(I) below corrosive liquid of the present invention is elaborated.
At first, with Fig. 7 A explanation with hydrofluoric acid as situation at the wet chemistry corrosive liquid of the no electrolysis of porous silicon.
Fig. 7 A has showed with hydrofluoric acid and has soaked into.During corrosion of porous silicon, the dependence between its thickness and the etching time.This porous silicon carries out anodization by monocrystalline silicon and makes.Its condition is as described below.But, it should be noted that the original material that relies on anodization to obtain porous silicon is not defined as monocrystalline silicon, the silicon of other crystal structure also can.
The condition of preparation porous silicon is:
Applied voltage 2.6V
Current density 30mAcm
-2
Anodization solution HF: H
2O: C
2H
5OH=1: 1: 1
2.4 hours time
The thick 300 μ m of porous silicon
The porous silicon that porosity 56% will be made with this understanding at room temperature immerses in the hydrofluoric acid (stain) of 49% hydrofluoric acid (white circle) and 20%, and is stirred.Then measure the thickness of porous silicon attenuate.Porous silicon was eroded 90 μ m in about about 40 minutes fast in 49% solution, 72 μ m are corroded in 20% solution.Through 80 minutes 205 μ m that are corroded, it had an even surface corrosion evenly in 49% solution, and in 20% solution, 16 μ m then are corroded.
The concentration of corrosion rate and solution and temperature all have relation.The condition enactment of solution concentration and temperature is not in hindering practical scope.As lifting row, above-described be with solution concentration be taken as 49%, 20%, temperature adopts the situation of room temperature, yet might not be limited to the condition of enumerating among the present invention.Comparatively ideal is that hydrofluoric acid is taken in the scope of 5-95%, and temperature then adopts general temperature commonly used.
Porous silicon water after the corrosion when micro-analysis is done with secondary ion in its surface, does not detect any impurity towards Xian.
Below with reference to Fig. 6 A the etching characteristic that adopts hydrofluoric acid corrosion of porous silicon and non-porous silicon is illustrated, after this, illustrates that with Figure 1A and Figure 1B one side to the non-porous silicon substrate all becomes the example that the substrate of porous silicon corrodes.
Fig. 6 A is porous silicon and the thickness of monocrystalline silicon and the dependence figure between the etching time for illustrating that porous silicon and monocrystalline silicon are corroded when soaking into hydrofluoric acid respectively.Porous silicon is obtained through anodization by monocrystalline silicon, and its condition is the same.Making the original material of porous silicon by anodization, be not limited to monocrystalline silicon, also can be the silicon of other crystal structure.
To at room temperature immerse by the porous silicon that above-mentioned condition makes in the hydrofluoric acid (white circle), and be stirred.Measure the attenuate situation of this porous silicon thickness then.Porous silicon layer is fast corrosion about 40 minutes in 49% solution, the 90 μ m that are corroded, and in 49% solution, had an even surface through 80 minutes and erode 205 μ m equably.Corrosion rate is with existing dependence between solution concentration and the temperature.Solution concentration and temperature are set in and do not hinder in the practical scope.As an example, description be to get 49% the hydrofluoric acid and the condition of room temperature, yet might not be limited to these cited conditions of the present invention.Preferably the concentration of hydrofluoric acid is taken between the 5%-95%, and temperature is got the temperature of common employing.
In addition, the non-porous silicon that 500 μ m are thick at room temperature immerses in 49% the hydrofluoric acid (stain), and stirs.After this measure the attenuate situation of non-porous thickness.Through 120 minutes, non-porous silicon only was corroded less than 100_.Corrosion rate and solution concentration and temperature are almost irrelevant.
Porous silicon and non-porous silicon after the corrosion are washed with water, the secondary ion micro-analysis is done on its surface, do not find any impurity.
Shown in Figure 1A, the one side of monocrystalline substrate 22 becomes porous silicon 21 through whole anodization.After this, in the substrate immersion hydrofluoric acid with this structure (porous silicon/monocrystalline silicon), promptly present situation shown in Figure 1B.Promptly only removed porous silicon, had only monocrystalline substrate 22 not to be corroded, and preserve., just can selectively corrode as the corrosion barrier material with monocrystalline silicon porous silicon.
The following describes the porous silicon that the same one side at substrate is provided with and the example of monocrystalline silicon.
As shown in Figure 2, by anodization the part of the one side of monocrystalline substrate 32 is become porous silicon 31.The necessary current/voltage of anodization is according to about the height of the concentration of charge carrier.Thereby, rely on ion by proton and impurity to inject the carrier concentration that partly changes the single-crystal surface layer and just porous silicon can be set partly.Then, the substrate of this (porous silicon/monocrystalline silicon) structure is immersed in the hydrofluoric acid, promptly be the situation shown in Fig. 2 B, only porous silicon is removed, monocrystalline substrate 32 is not corroded and is retained, thereby can be to the porous silicon corrosion that elects.
Be described in the example that porous silicon/polysilicon layeredly is set on the one side of substrate below.
As shown in Figure 3A, rely on deposit, polysilicon layer 41 is set on monocrystalline substrate 42.Make the polysilicon surface layer become porous silicon layer 43 (Fig. 3 B) by the anodization method.After this, the substrate of this (porous silicon/polycrystalline/monocrystalline silicon) structure is immersed in the hydrofluoric acid, promptly can present the situation shown in Fig. 3 C, only remove porous silicon, and monocrystalline substrate 42 and polysilicon layer 41 do not remain with being corroded, thereby can porous silicon be corroded selectively with polysilicon as the corrosion barrier material.
The following describes the example that porous silicon is set on the part of the polysilicon layer surface of a side of substrate.
Shown in Fig. 4 A, on monocrystalline substrate 52, polysilicon layer 51. is set and adopts the anodization method by sedimentation, make the part of polysilicon surface become porous silicon 53 (Fig. 4 A).After this substrate with this (porous silicon/polycrystalline silicon/monocrystalline silicon) structure immerses in the hydrofluoric acid, promptly present the situation shown in Fig. 4 C, only porous silicon is removed, and monocrystalline substrate 52 and polysilicon layer 51 are not corroded and remain, thereby corrosion of porous silicon selectively.
Fig. 7 B has illustrated that the mixed liquor with hydrofluoric acid and (second) alcohol does not have the situation of corrosive liquid of the wet corrosion of electrolysis to porous silicon with work.
In Fig. 7 B, express when in hydrofluoric acid and ethanol and mixed liquor, not soaking into the thickness of porous silicon and the dependence between the etching time with stirring.Porous silicon is made through anodization by monocrystalline silicon, and its condition is as follows.And the original material that is formed porous silicon by the anodization method is not limited to monocrystalline silicon, and the silicon of other crystal structure also can.
Anodized condition is:
Applied voltage 2.6V
Current density 30mAcm
-2
Anodization solution HF: H
2O: C
2H
5OH=1: 1: 1
2.4 hours time
The thick 300 μ m of porous silicon
Porosity 56% will at room temperature immerse by the porous silicon that this condition is made in the mixed liquor (10: 1) (stain) of the mixed liquor (10: 1) (white circle) of 49% hydrofluoric acid and ethanol and 20% hydrofluoric acid and ethanol, not add stirring.Measure the attenuate situation of this porous silicon then.Porous silicon is corroded in the mixed liquor (10: 1) of 49% solution and ethanol fast, reaches 85 μ m in about 40 minutes.And the 68 μ m that in the mixed liquor (10: 1) of 20% solution and ethanol, are corroded, in addition, through 80 minutes, in the mixed liquor (10: 1) of 49% solution and ethanol, erode 95 μ m, have an even surface and evenly, and in the mixed liquor (10: 1) of 20% solution and ethanol, 156 μ m then are corroded.The concentration of corrosion rate and hydrofluoric acid and temperature correlation.Owing to added ethanol, the bubble of the reacting gas that produces by corrosion, without stirring, the instant can be removed by corrosion surface, thereby can be evenly and corrosion of porous silicon expeditiously.
Solution concentration and temperature conditions can be set in and make corrosion rate make the usage range that is not hindered in the operation and make in the scope that above-mentioned ethanol works in system.This example is the mixed liquor (10: 1) of 49% hydrofluoric acid and ethanol and 20% hydrofluoric acid and the mixed liquor (10: 1) of ethanol, the situation that temperature is got room temperature for adopting solution concentration, yet is not limited to the cited condition of the present invention.
For corrosive liquid, HF concentration can be set in 1-95%, preferably at 5-90%, preferably in the scope of 5-80%.(second) determining alcohol as for corrosive liquid can be set in below 80%, and more fortunately 60%, be preferably in below 40%, and can play in the scope of effect of above-mentioned (second) alcohol.As for temperature can be set in 0-100 ℃, preferably 5-80 ℃, preferably in 5-60 ℃ scope.
Be used for alcohol of the present invention, except that ethanol, also can use isopropyl alcohol one class on production process, not hinder practical alcohol and can play alcohol with the additive effect of above-mentioned alcohol.
Porous silicon after the corrosion washes through water, and the secondary ion micro-analysis is done on its surface, does not check out any impurity.
Utilize Fig. 6 B that the characteristic of the porous silicon non-porous silicon being corroded by hydrofluoric acid and alcohol mixeding liquid is described below.
In Fig. 6 B, showed porous silicon and monocrystalline silicon have not been had porous silicon and the thickness of monocrystalline silicon and the dependence between the etching time that stirs when soaking into through the mixed liquor of hydrofluoric acid and ethanol respectively.Porous silicon is made through the anodization operation by monocrystalline silicon, and its condition is same as described above.Be used for being made by anodization the original material of porous silicon, the silicon that is not limited to monocrystalline silicon, other crystal structure can also use.
The test piece of the porous silicon that will make by above-mentioned condition is soaked under stirring condition not in the mixed liquor (10: 1) (white circle) of 49% hydrofluoric acid and ethanol, measures the attenuate situation of this porous silicon thickness.The result is that porous silicon is corroded fast, reaches 85 μ m in about 40 minutes, and the 195 μ m that are corroded after through 80 minutes.It has an even surface, corrodes evenly.
Corrosion rate is relevant with the concentration and the temperature of hydrofluoric acid.By the alcohol that adds, make to need not to stir and can remove the bubble of the reacting gas that produces because of corrosion very soon by corrosion surface, thus can be evenly and carry out the porous silicon corrosion efficiently.
The non-porous silicon that 500 μ m are thick does not at room temperature soak in the mixed liquor (10: 1) (stain) of 49% hydrofluoric acid and ethanol with mixing, measures the attenuate situation of this non-porous silicon thickness then.This non-porous silicon only is corroded less than 100_ after through 120 minutes.Corrosion rate and solution concentration and temperature are nearly all irrelevant.
Porous silicon and non-porous silicon after the corrosion wash through water, when the secondary ion micro-analysis is done on its surface, do not detect any impurity.
Do at the mixed liquor that uses hydrofluoric acid and a kind of alcohol also can be attained at certainly in above-mentioned (1) with Figure 1A-1B, Fig. 2 A-2B, Fig. 3 A-3C and the illustrated state of Fig. 4 A-4C under the situation of corrosive agent of porous silicon.
Utilize Fig. 7 C to come now to being illustrated with the mixed liquor of hydrofluoric acid and hydrogen peroxide situation as the wet chemistry corrosive liquid that porous silicon is not had electrolysis.
Showed among Fig. 7 C with the mixture liquid of hydrofluoric acid and hydrogen peroxide and soaked into and when stirring the thickness of the porous silicon that is corroded and the relation between the etching time.Porous silicon is made through anodization by monocrystalline silicon.Its condition is as follows.Be not limited to monocrystalline silicon as anodization with the original material that forms porous silicon, the silicon of other crystal structure also can.
Its condition is as follows
Applied voltage 2.6V
Current density 30mAcm
-2
Anodization solution HF: H
2O: C
2H
5OH=1: 1: 1
2.4 hours time
The thick 300 μ m of porous silicon
Porosity 56% will at room temperature be soaked into by the porous silicon that above-mentioned condition is made in the mixed liquor (1: 1) (stain) of the hydrofluoric acid of the mixed liquor (1: 5) of 49% hydrofluoric acid and hydrogen peroxide (white circle) and 49% and hydrogen peroxide and be stirred.Then measure the situation of this porous silicon reduced thickness.Porous silicon is corroded rapidly, at 1: 5 in solution, 112 μ m were corroded in about 40 minutes, and in 1: 1 solution, the 135 μ m that then are corroded, and, after through 80 minutes, in 1: 5 solution, the surface 256 μ m that on average are corroded equably, and the 307 μ m that in 1: 1 solution, are corroded.Here the concentration of hydrogen peroxide is 30%, also can be set in the following concentration that does not hinder practicality without detriment to the additive effect of hydrogen peroxide and in production process.
And corrosion rate depends on the solution concentration and the temperature of hydrofluoric acid and hydrogen peroxide.Can quicken the oxidation of silicon because of adding hydrogen peroxide, thereby comparablely improve reaction speed when not adding hydrogen peroxide, and rely on the ratio that changes hydrogen peroxide to get final product controls reaction speed.
Solution concentration and temperature conditions can be set in hydrofluoric acid and above-mentioned hydrogen peroxide works and corrosion rate does not hinder in manufacturing process in the practical scope.In this application as an example, take mixed liquor (1: 5) and 49% the hydrofluoric acid and the mixed liquor (1: 5) of hydrogen peroxide of 49% hydrofluoric acid and hydrogen peroxide, the temperature room temperature, however be not limited to these cited conditions of the present invention.
About corrosive liquid, HF concentration can be set in 1-95%, is 5-90% preferably, is preferably in the scope of 5-80%.H in the corrosive liquid
2O
2Concentration can be set in 1-95%, and 5-90% is preferably in 10-80% more fortunately, and makes in the scope that above-mentioned hydrogen peroxide works.
Porous silicon after the corrosion washes through water, when the secondary ion micro-analysis is done on its surface, does not detect any impurity.
When utilizing Fig. 6 C explanation to adopt the mixed liquor of hydrofluoric acid and hydrogen peroxide below to the etching characteristic of porous silicon and amorphous silicon.
When Fig. 6 C represents that porous silicon and monocrystalline silicon immerse the mixed liquor of hydrofluoric acid and hydrogen peroxide respectively, the dependence between the porous silicon that is corroded and monocrystalline silicon thickness and the etching time.Porous silicon is made by anodization, and its condition is with top described identical.The original material that obtains porous silicon with anodization is not limited to monocrystalline silicon, also is fine with the silicon of other crystal structure.
To at room temperature be immersed in by the porous silicon that above-mentioned condition is made in the mixed liquor (1: 5) (white circle) of 49% hydrofluoric acid and hydrogen peroxide, and be stirred.Measure the situation of this porous silicon reduced thickness then.Porous silicon is corroded fast, reaches 112 μ m in about 40 minutes, and through after 80 minutes, has an even surface and erodes 256 μ m equably.Here hydrogen peroxide concentration is decided to be 30%, is not hindering practical concentration without detriment to the effect of following interpolation hydrogen peroxide and in manufacturing process yet also can be set.
Corrosion rate depends on the concentration and the temperature of hydrofluoric acid and hydrogen peroxide.Add hydrogen peroxide the oxidation of silicon is accelerated, thereby it is fast when not adding to make reaction speed, and can come controls reaction speed by the ratio that changes hydrogen peroxide.
In addition, the non-porous silicon of 500 μ m at room temperature is dipped in the mixed liquor (1: 5) (stain) of 49% hydrofluoric acid and hydrogen peroxide, and is stirred.Measure the situation of this non-porous silicon reduced thickness then.After through 120 minutes, non-porous silicon only is corroded less than 100_.As seen corrosion rate and solution concentration reach with temperature almost irrelevant.
Porous silicon and non-porous silicon after the corrosion wash through water, and micro-analysis is done with secondary ion in its surface, do not detect any impurity.
Under the situation of mixed liquor of using hydrofluoric acid and hydrogen peroxide, also can be attained at above-mentioned certainly with illustrated state among Figure 1A-1B, Fig. 2 A-2B, Fig. 3 A-3C and Fig. 4 A-4C as the corrosive agent of porous silicon.
With Fig. 7 D the situation of the mixed liquor of employing hydrofluoric acid, alcohol and hydrogen peroxide as the corrosive liquid of the wet chemistry corrosion of porous silicon not being had electrolysis is described below.
Its thickness that is corroded is with the dependence between the etching time when showing porous silicon among Fig. 7 D and not soaking in the mixed liquor of hydrofluoric acid, ethanol and hydrogen peroxide with stirring.Porous silicon is formed through anodization by polysilicon.Its condition is as described below.Make the original material of porous silicon with anodization, still be not limited to monocrystalline silicon, the silicon of other crystal structure also can.
The anodization condition:
Applied voltage 2.6V
Current density 30mAcm
-2
Anodization solution HF: H
2O: C
2H
5OH=1: 1: 1
2.4 hours time
The thick 300 μ m of porous silicon
Porosity 56% will at room temperature be dipped in by the porous silicon that above-mentioned condition makes in the mixed liquor (10: 6: 50) (white circle) of 49% hydrofluoric acid, ethanol and hydrogen peroxide, and in the mixed liquor of 49% hydrofluoric acid, ethanol and hydrogen peroxide (10: 2: 10) (stain), do not add stirring.After this, measure the attenuate situation of this porous silicon thickness.Porous silicon is corroded rapidly, about 40 minutes 107 μ m that are corroded in 10: 6: 50 solution, and in 10: 2: 10 solution, 128 μ m are corroded.After through 80 minutes, in 10: 2: 10 solution, 292 μ m are corroded.Though the solution concentration of hydrogen peroxide is decided to be 30% here, yet also can be set in without detriment to following interpolation hydrogen peroxide effect and in production process, hinder practical concentration.
Also have, corrosion rate depends on the solution concentration and the temperature of hydrofluoric acid, hydrogen peroxide.Increase hydrogen peroxide, can quicken the oxidation of silicon, and, by changing the ratio of hydrogen peroxide, can control its reaction speed.In addition, owing to added alcohol, thereby need not stir, instantaneously just can remove the bubble that corrosion reaction produces, can corrode porous Si evenly, efficiently from corrosion surface.
With regard to the scope of solution concentration and temperature conditions, hydrofluoric acid and above-mentioned hydrogen peroxide and above-mentioned alcohol are worked, make corrosion rate not hinder practicality at aspects such as manufacturing process.Though adopt the mixed liquor (10: 6: 50) of 49% hydrofluoric acid, ethanol and hydrogen peroxide under the room temperature and the mixed liquor (10: 2: 10) of 49% hydrofluoric acid, ethanol and hydrogen peroxide in the example, the present invention is not limited to above-mentioned condition.
For corrosive liquid, HF concentration can be decided to be 1～95%, and is with 5～90% better, better in 5～80% scope.In the corrosive liquid, H
2O
2Concentration can be 1～95%, and is better in 10～10% scopes with 5～90% better, and all be set in the scope that above-mentioned hydrogen peroxide works.In the corrosive liquid, the concentration of alcohol can be lower than 80%, is lower than 60% better, is preferably in below 40%, and all is set in the scope that above-mentioned alcohol works.Temperature is set at 0～100 ℃ for well, with 6～80 ℃ better, and 5-60 ℃ scope is better.
Be used for alcohol of the present invention except that ethanol, can also use isopropyl alcohol etc. those do not hinder practical alcohol at aspects such as manufacturing process, and other can play the alcohol of the additive effect of above-mentioned alcohol.
Porous Si after the corrosion is through washing, and micro-analysis is done with the secondary ion method in its surface, does not detect any impurity.
Under the situation of this corrosive liquid, make the bubble of corrosion reaction generation need not stir instantaneous can removing by adding alcohol, thereby make small recess can form extremely smooth, uniform bottom from corrosion surface.
Below, utilize Fig. 6 D, hydrofluoric acid, ethanol and the hydrogen peroxide mixed liquor etching characteristic to porous Si and non-porous Si is described.
Fig. 6 D represents, porous Si and single crystalline Si are immersed in the mixed liquor of various hydrofluoric acid, ethanol and hydrogen peroxide and do not add when stirring the corrosion thickness of porous Si and single crystalline Si and the relation of etching time.Porous Si is formed by the single crystalline Si anodization, and its condition is same as described above.The raw material that anodization forms porous Si are not limited to single crystalline Si, also are fine with the Si of other crystalline texture.
The porous Si that makes by above-mentioned condition is soaked in the mixed liquor (10: 6: 50) (white circle) of at room temperature 49% hydrofluoric acid, ethanol and hydrogen peroxide, do not add stirring, measure the minimizing of this porous Si thickness then.Porous Si is promptly corroded, and after about 40 minutes, erodes 107 μ m, then erodes 244 μ m after 80 minutes, also has the profile pattern of height, and corrosion evenly.The concentration of hydrogen peroxide solution though be 30% here, can be set at the following additive effect of not losing hydrogen peroxide and do not hinder practical concentration in manufacturing process.
Also have, corrosion rate depends on the solution concentration and the temperature of hydrofluoric acid, hydrogen peroxide.Can accelerate the oxidation of silicon by increasing hydrogen peroxide, compare when not adding hydrogen peroxide, can fast reaction speed, and just can control its reaction speed by the ratio that changes hydrogen peroxide.And, by adding alcohol, then need not stir, instantaneously just can remove the bubble that corrosion reaction produces from corrosion surface, can corrode porous Si efficiently, equably.
In addition, the non-porous Si that 500 μ m are thick soaks in the mixed liquor (10: 6: 50) (stain) of at room temperature 49% hydrofluoric acid, ethanol and hydrogen peroxide, does not add stirring, measures the minimizing of this non-porous Si thickness then.Even after 120 minutes, non-porous Si also only is corroded less than 100 dusts.Corrosion rate is almost irrelevant with the concentration and the temperature of solution.
Porous Si after the corrosion and non-porous Si do micro-analysis to its surface with the secondary ion method through washing, do not detect any impurity.
Obviously also can obtain under with the mixed liquor of hydrofluoric acid, pure and mild hydrogen peroxide as the situation of the corrosive liquid of porous Si in above-mentioned (1), with Figure 1A-Figure 1B, Fig. 2 A-Fig. 2 B, Fig. 3 A-Fig. 3 C and the illustrated various caustic solutions of Fig. 4 A-Fig. 4 C.
About the situation of the hydrofluoric acid that cushioned, will be illustrated with Fig. 7 E as the no electrolysis wet chemistry corrosive liquid of porous Si.
As for buffered hydrofluoric acid, can use for example ammonium fluoride (NH
4F) 36.2%, the aqueous solution of hydrogen fluoride (HF) 4.5%.
Fig. 7 E is illustrated in the buffered hydrofluoric acid in addition under the condition of stirring, the corrosion thickness of porous Si and the relation of etching time.Porous Si is made by the single crystalline Si anodization, and its condition is following listed.In addition, the raw material that anodization forms porous Si are not limited to single crystalline Si, and the Si of other crystalline texture also is fine.
Applied voltage 2.6V
Current density 30mAcm
-2
Anodization solution HF: H
2O: C
2H
5OH=1: 1: 1
2.4 hours time
The thick 300 μ m of porous silicon
It is in 20% the buffered hydrofluoric acid (stain) that porosity 56% at room temperature will be immersed in buffered hydrofluoric acid (white circle) or dilution by the porous Si that above-mentioned condition is made, and is stirred.Then, measure the minimizing of this porous Si thickness.Porous Si is corroded apace, after about 40 minutes, and the 70 μ m that in buffered hydrofluoric acid, are corroded, 56 μ m are corroded in 20% dilute solution.And through after 120 minutes, the 118 μ m that in buffered hydrofluoric acid, are corroded, and corrosion evenly, have the profile pattern of height, in 20% dilute solution, 94 μ m then are corroded.
In addition, corrosion rate depends on the concentration and the temperature of solution.The concentration of solution and temperature conditions are set in and do not hinder in the practical scope.Though described employing ammonium fluoride (NH above
4F) 36.2%, the aqueous solution of hydrogen fluoride (HF) 4.5% makes buffered hydrofluoric acid, perhaps 20% dilution buffer hydrofluoric acid, and temperature is got room temperature, but the present invention is not limited to this condition.
HF concentration in the buffered hydrofluoric acid, for corrosive liquid, given scope can be 1-95%, and is better with 1-85%, better in the scope of 1-70%.NH in the buffered hydrofluoric acid
4F concentration, concerning corrosive liquid, given scope can be 1-95%, and is better with 5-90%, better in the scope of 5-80%.Temperature can be decided to be 0-100 ℃, with 5-80 ℃ better, and 5-60 ℃ better.
Porous Si after the corrosion does micro-analysis to its surface with the secondary ion method through washing, does not detect any impurity.
Below, with Fig. 6 E the etching characteristic of relevant buffered hydrofluoric acid to porous Si and non-porous Si is described.
Fig. 6 E represents, when porous Si and single crystalline Si are immersed in the various buffered hydrofluoric acids, and the corrosion thickness of porous Si and single crystalline Si and the relation of etching time.Porous Si is made through anodization by single crystalline Si, and its condition is same as described above.The raw material that anodization forms porous Si are not limited to single crystalline Si, and the Si of other crystalline texture also is fine.
At room temperature, be not immersed in the buffered hydrofluoric acid (white circle) with will not adding stirring by the porous Si that above-mentioned condition is made, then, measure the minimizing of this porous Si thickness.Porous Si promptly is corroded, in this solution through the 70 μ m that are corroded after 40 minutes, and in this solution through after 120 minutes, the 118 μ m that then are corroded, and profile pattern, corrosion with height are evenly.In addition, corrosion rate depends on the concentration and the temperature of solution.The condition enactment of solution concentration and temperature is not in hindering practical scope.Among the application, as an example employing is ammonium fluoride (NH
4F) 36.2%, the solution of the water of hydrogen fluoride (HF) 4.5% makes buffered hydrofluoric acid, and temperature gets room temperature, but the invention is not restricted to such solution concentration and temperature conditions.
And the non-porous Si that 500 μ m are thick at room temperature is immersed in the buffered hydrofluoric acid (stain), does not add stirring.Then, measure the minimizing of this non-porous Si thickness.Even after 120 minutes, non-porous Si also only is corroded less than 100 dusts.Corrosion rate is almost irrelevant with the concentration and the temperature of solution.
Porous Si after the corrosion and non-porous through washing does micro-analysis to its surface with the secondary ion method, does not detect any impurity.
Obviously, at the various caustic solutions that also can obtain under with buffered hydrofluoric acid to be explained with reference to figure 1A-Figure 1B, Fig. 2 A-Fig. 2 B, Fig. 3 A-Fig. 3 C and Fig. 4 A-Fig. 4 C in above-mentioned (I) as the situation of the corrosive liquid of porous Si.
With Fig. 7 F explanation with the mixed liquor of buffered hydrofluoric acid and alcohol situation as the no electrolysis wet chemistry corrosive liquid of porous Si.
As for buffered hydrofluoric acid, for example, adopt ammonium fluoride (NH
4F) 36.2%, the aqueous solution of hydrogen fluoride (HF) 4.5%.
Fig. 7 F represents, does not add the corrosion thickness of the porous Si that stirs and soaking and the relation of etching time in the mixed liquor of buffered hydrofluoric acid and (second) alcohol.Porous Si is made through anodization by single crystalline Si.Its condition is following listed.In addition, the raw material that form porous Si by anodization are not limited to single crystalline Si, and the Si of other crystalline texture also is fine.
Applied voltage 2.6V
Current density 30mAcm
-2
Anodization solution HF: H
2O: C
2H
5OH=1: 1: 1
2.4 hours time
The thick 300 μ m of porous silicon
Porosity 56% will at room temperature be immersed in by the porous Si that above-mentioned condition is made in the mixed liquor (10: 1) (stain) of mixed liquor (10: 1) (white circle), 20% dilution buffer hydrofluoric acid and ethanol of buffered hydrofluoric acid and ethanol, do not add stirring, measure the minimizing of this porous Si thickness then.Porous Si promptly is corroded, after about 40 minutes, and 67 μ that in the mixed liquor (10: 1) of buffered hydrofluoric acid and ethanol, are corroded ±, 54 μ m are corroded in the mixed liquor (10: 1) of dilution buffer hydrofluoric acid 20% and ethanol.And through after 120 minutes, porous silicon 112 μ m that are corroded in the mixed liquor (10: 1) of buffered hydrofluoric acid and ethanol, and the profile pattern of height is arranged, corrosion evenly, 90 μ m are corroded in dilute solution 20% and the alcohol mixeding liquid (10: 1).
Also have, corrosion rate depends on the solution concentration and the temperature of buffered hydrofluoric acid.By adding alcohol, need not stir.Instantaneously just can remove the bubble that produces because of corrosion reaction, and can evenly and efficiently erode porous Si from the surface of corrosion.
In manufacturing process, the concentration of solution and temperature conditions are set in and do not hinder in the scope that practicality and above-mentioned ethanol works.Though this example adopts the mixed liquor (10: 1) of mixed liquor (10: 1), 20% dilute solution and ethanol of buffered hydrofluoric acid and ethanol as corrosive liquid, and temperature gets room temperature, the invention is not restricted to such solution concentration and temperature conditions.
Concerning corrosive liquid, the HF concentration in the buffered hydrofluoric acid can be set at 1-95%, and is better with 1-85%, better in the scope of 1-70%; NH in the buffered hydrofluoric acid
4The concentration of F can be set at 1-95%, and is better with 5-90%, better in the scope of 5-80%; The concentration of alcohol can be set in below 80%, and is better, better below 40% below 60%, and will be in the scope of the effect that plays above-mentioned alcohol.Temperature can be set at 0-100 ℃, with 5-80 ℃ better, better in 5-60 ℃ of scope.
Be used for alcohol of the present invention except that ethanol, can also on manufacturing process, do not hinder practicality and play the alcohol of the additive effect of above-mentioned alcohol with isopropyl alcohol etc.
Porous Si after the corrosion is through washing, and micro-analysis is done with the secondary ion method in its surface, does not detect any impurity.
Under the situation of this corrosive liquid, owing to added alcohol, needn't stir just and can instantaneously remove the bubble that produces because of corrosion reaction from corrosion surface, can the smooth bottom of adequate relief poling at small recess.
Below, with Fig. 6 F relevant porous Si and the etching characteristic of non-porous Si in buffered hydrofluoric acid and alcohol mixeding liquid are described.
Fig. 6 F represents, porous Si and single crystalline Si is immersed in the porous Si and the corrosion thickness of single crystalline Si and the relation of etching time that do not add in the mixed liquor of various buffered hydrofluoric acids and ethanol when stirring.Porous Si is made through anodization by single crystalline Si by single crystalline Si, and its condition is same as described above.The raw material that utilize anodization to form porous Si are not limited to single crystalline Si, and the Si of other crystalline texture also is fine.
At room temperature, will be immersed in by the porous Si that above-mentioned condition is made in the mixed liquor (10: 1) (white circle) of buffered hydrofluoric acid and ethanol, not add stirring.Then, measure the minimizing of this porous Si thickness.The result is that porous Si promptly is corroded, and the 67 μ m that are corroded after about 40 minutes through the 112 μ m that are corroded after 120 minutes, also have the profile pattern of height, corrode also even.
In addition, at room temperature thick non-porous of 500 μ m is immersed in the mixed liquor of buffered hydrofluoric acid and ethanol, do not add stirring.Then, measure the minimizing of this non-porous Si thickness.Even through 120 minutes, the etching extent of non-porous Si is also less than 100 dusts.The speed of corrosion is almost irrelevant with the concentration and the temperature of solution.
Porous Si after the corrosion and non-porous Si do micro-analysis to its surface with the secondary ion method after washing, do not detect any impurity.
Obviously, under the situation of mixed liquor, also can obtain in above-mentioned (I) with reference to figure 1A-Figure 1B, Fig. 2 A-Fig. 2 B, Fig. 3 A-Fig. 3 C and the illustrated various caustic solutions of Fig. 4 A-Fig. 4 C as the corrosive liquid of porous Si with buffered hydrofluoric acid and alcohol.
With Fig. 7 G explanation with the mixed liquor of buffered hydrofluoric acid and hydrogen peroxide situation as the no electrolysis wet chemistry corrosive liquid of porous Si.
As for buffered hydrofluoric acid, for example, with ammonium fluoride (NH
4F) 36.2%, the aqueous solution of hydrogen fluoride (HF) 4.5%.
Fig. 7 G represents, porous Si is immersed in the mixed liquor of buffered hydrofluoric acid and hydrogen peroxide, does not add when stirring the corrosion thickness of porous Si and the relation of etching time.Porous Si is made through anodization by single crystalline Si, and its condition is following listed.In addition, the raw material that anodization forms porous Si are not limited to single crystalline Si, and the Si of other crystalline texture also is fine.
Applied voltage 2.6V
Current density 30mAcm
-2
Anodization solution HF: H
2O: C
2H
5OH=1: 1: 1
2.4 hours time
The thick 300 μ m of porous silicon
Porosity 56% will at room temperature be immersed in by the porous Si that above-mentioned condition is made in the mixed liquor (1: 5) (white circle) of buffered hydrofluoric acid and hydrogen peroxide, perhaps immerse in the mixed liquor (5: 1) (stain) of buffered hydrofluoric acid and hydrogen peroxide, not add stirring.Then, measure the minimizing of this porous Si thickness.Porous Si is corroded rapidly, after about 40 minutes, erodes 88 μ m in 1: 5 solution, and erode 105 μ m in 5: 1 solution.After 120 minutes, porous silicon erodes 147 μ m in 1: 5 solution, and corrodes even, as to have height profile pattern; In 5: 1 solution, then erode 117 μ m.The concentration of hydrogen peroxide solution though be 30% here, can be set at the additive effect of not losing following hydrogen peroxide and do not hinder practical concentration in manufacturing process.
Also have, corrosion rate depends on the concentration and the temperature of buffered hydrofluoric acid, hydrogen peroxide.By adding hydrogen peroxide, can quicken the oxidation of silicon, and can make reaction speed faster than added-time not, in addition, can controls reaction speed by the ratio that changes hydrogen peroxide.
With regard to the condition of solution concentration and temperature, allow buffered hydrofluoric acid and hydrogen peroxide work, make reaction speed in manufacturing process, not hinder practicality.Though the mixed liquor (1: 5) of this example employing buffered hydrofluoric acid and hydrogen peroxide or the mixed liquor (5: 1) of buffered hydrofluoric acid and hydrogen peroxide are as corrosive liquid, and the employing room temperature, the present invention is not limited to such solution concentration and temperature conditions.
For corrosive liquid, the HF concentration in the buffered hydrofluoric acid can be set at 1-95%, and is better with 1-85%, and the scope of 1-70% is better; NH in the buffered hydrofluoric acid
4F concentration can be set at 1-95%, and is better with 1-90%, and the scope of 5-80% is better; H
2O
2Concentration, can be set at 1-95%, better with 5-90%, and the scope of 10-80% is better, and be set in the scope that above-mentioned hydrogen peroxide works.Temperature can be set at 0-100 ℃, with 5-80 ℃ better; And it is better in 5-60 ℃ scope.
Porous Si after the corrosion does micro-analysis to its surface with the secondary ion method through washing, does not detect any impurity.
When Fig. 6 G represents to be immersed in porous Si and single crystalline Si in the mixed liquor of various buffered hydrofluoric acids and hydrogen peroxide, the corrosion thickness of porous Si and single crystalline Si and the relation of etching time.Porous Si is made through anodization by single crystalline Si, and its condition is same as described above.The raw material that form porous Si in order to anodization are not limited to single crystalline Si, and the Si of other crystalline texture also is fine.
The porous Si that will make by above-mentioned condition soaks at room temperature the buffered hydrofluoric acid and the mixed liquor (1: 5) (white circle) of hydrogen peroxide, does not add stirring.Then, measure the minimizing of this porous Si thickness.Porous Si is corroded rapidly, and post-etching fell 88 μ m in about 40 minutes, then erodes 147 μ m after 120 minutes, and corrosion evenly has the profile pattern of height again.The solution concentration of hydrogen peroxide though be 30%, can be set at the concentration that does not hinder its additive effect and do not hinder practicality in manufacturing process here.
Porous Si after the corrosion and non-porous Si do micro-analysis to its surface with the secondary ion method through washing, do not detect any impurity.
Obviously, under the situation of mixed liquor, also can obtain in above-mentioned (I) with reference to figure 1A-Figure 1B, Fig. 2 A-Fig. 2 N, Fig. 3 A-Fig. 3 C and the illustrated various caustic solutions of Fig. 4 A-Fig. 4 C as the corrosive liquid of porous Si with buffered hydrofluoric acid and hydrogen peroxide.
With Fig. 7 H explanation with the mixed liquor of buffered hydrofluoric acid, pure and mild hydrogen peroxide situation as the no electrolysis wet chemistry corrosive liquid of porous Si.
As for buffered hydrofluoric acid, use ammonium fluoride (NH
4F) 36.2%, the aqueous solution of hydrogen fluoride (HF) 4.5%.
Fig. 7 H represents not add the corrosion thickness of porous Si when stirring in the mixed liquor that ground is immersed in the porous silicon sample in buffered hydrofluoric acid, ethanol and hydrogen peroxide and the relation of etching time.Porous Si is made through anodization by single crystalline Si, and its condition is following listed.In addition, the raw material that anodization forms porous Si are not limited to single crystalline Si, and the Si of other crystalline texture also is fine.
Applied voltage 2.6V
Current density 30mAcm
-2
Anodization solution HF: H
2O: C
2H
5OH=1: 1: 1
2.4 hours time
The thick 300 μ m of porous silicon
Porosity 56% will not add in the mixed liquor (10: 6: 50) (white circle) that stirs ground and soak at room temperature buffered hydrofluoric acid, ethanol and hydrogen peroxide by the porous Si that above-mentioned condition is made or in the mixed liquor (50: 6: 10) (black circle) of buffered hydrofluoric acid, ethanol and hydrogen peroxide.Then, measure the minimizing of this porous Si thickness.Porous Si is corroded rapidly, after about 40 minutes, erodes 83 μ m in 10: 6: 50 solution; In 50: 6: 10 solution, erode 100 μ m.And through after 120 minutes, erode 140 μ m in 10: 6: 50 solution, and corrosion evenly has the profile pattern of height again; In 50: 6: 10 solution, erode 168 μ m.The concentration of hydrogen peroxide though be 30%, can be set at its additive effect of forfeiture here, and do not hinder practical concentration in manufacturing process.
Also have, corrosion rate depends on the solution concentration and the temperature of buffered hydrofluoric acid, hydrogen peroxide.Can quicken the oxidation of silicon because of adding hydrogen peroxide, than the reaction speed of not added-time fast, and since reaction speed change with the variation of the ratio of hydrogen peroxide, thereby, can control its reaction speed.Moreover, owing to add alcohol, thereby, needn't stir, just can remove the instantaneous surface of the bubble that corrosion reaction produces, thereby can efficiently corrode porous Si equably from corrosion.
The Pressure, Concentration, Temperature condition of solution will be set in buffered hydrofluoric acid and above-mentioned hydrogen peroxide and above-mentioned alcohol are worked, and corrosion rate is not hindered in manufacturing process in the practical scope.Among the application, as an example, though adopt buffered hydrofluoric acid, ethanol and hydrogen peroxide mixed liquor (10: 6: 50), buffered hydrofluoric acid, ethanol and hydrogen peroxide mixed liquor (50: 6: 10) and adopt room temperature, the present invention is not limited to this condition.
For corrosive liquid, the HF concentration in the buffered hydrofluoric acid can be set in 1-95%, and is better with 1-85%, and better in the scope of 1-70%, the NH in the buffered hydrofluoric acid
4F concentration can be set in 1-95%, and is better with 5-90%, and better in the scope of 5-80%; H
2O
2Concentration can be set at 1-95%, better with 5-90%, and better in the scope of 10-80%, and will be in the scope that it works; The concentration of alcohol can be set in below 80%, and is better to be lower than 60%, and be lower than 40% better, and in the scope that it works.Temperature will be set at 0-100 ℃, with 5-80 ℃ better, and better in 5-60 ℃ scope.
Except that ethanol, be used for the alcohol that alcohol of the present invention can also use isopropyl alcohol etc. not hinder practical alcohol on manufacturing process and have the additive effect of above-mentioned alcohol.
Porous Si after the corrosion does micro-analysis to its surface with the secondary ion method through washing, does not detect any impurity.
Owing to added alcohol in this corrosive liquid, need not stir, instantaneously just can remove the bubble that corrosion reaction produces from corrosion surface, so, also can form extremely smooth, uniform bottom at small recess.
Obviously, under the situation of mixed liquor, also can realize in above-mentioned (I) with reference to figure 1A-Figure 1B, Fig. 2 A-Fig. 2 B, Fig. 3 A-Fig. 3 C and the illustrated embodiment of Fig. 4 A-Fig. 4 C as the corrosive liquid of porous Si with buffered hydrofluoric acid, pure and mild hydrogen peroxide.
Claims (13)
1. the corrosive liquid of a selective corrosion porous silicon from the substrate, described substrate is made of porous silicon and non-porous silicon, it is characterized in that: this corrosive liquid comprises one by at least a solution of forming in hydrofluoric acid and alcohol and the hydrogen peroxide, or one by buffered hydrofluoric acid and a kind of solution of forming in alcohol and the hydrogen peroxide at least.
2. corrosive liquid as claimed in claim 1 is characterized in that, described corrosive liquid is by the hydrogen peroxide of a hydrofluoric acid that comprises 5-80%, 10-80% and be less than and equal the solution composition that 40% alcohol is formed.
3. corrosive liquid as claimed in claim 1 is characterized in that, described corrosive liquid comprises 5～80% buffered hydrofluoric acid, 10～80% hydrogen peroxide by one and smaller or equal to the solution composition of 40% alcohol.
4. corrosive liquid as claimed in claim 1 is characterized in that, described corrosive liquid is by a solution composition that comprises the hydrogen peroxide of 5～80% hydrofluoric acid and 10～80%.
5. corrosive liquid as claimed in claim 1 is characterized in that, described corrosive liquid comprises 5～80% hydrofluoric acid by one and is less than the solution composition that equals 40% alcohol.
6. corrosive liquid as claimed in claim 1 is characterized in that, described corrosive liquid is by a solution composition that comprises the hydrogen peroxide of 5～80% buffered hydrofluoric acid and 10～80%.
7. corrosive liquid as claimed in claim 1 is characterized in that, described corrosive liquid comprises 5～80% hydrofluoric acid by one and is less than the solution composition that equals 40% alcohol.
8. corrosive liquid as claimed in claim 1 is characterized in that, described alcohol is ethanol.
9. corrosive liquid as claimed in claim 1 is characterized in that buffered hydrofluoric acid is made of a kind of ammonium fluoride and hydrofluoric solution of comprising.
10. the method for a selective corrosion porous silicon from the substrate, described substrate is made of porous silicon and non-porous silicon, it is characterized in that, and corrosion is carried out with each described corrosive liquid among the claim 1-11.
11. the method as the corrosion of porous silicon of claim 10 is characterized in that corrosion is to carry out under 0～100 ℃ temperature.
12. the method as the corrosion of porous silicon of claim 11 is characterized in that corrosion is to carry out under 5～80 ℃ temperature.
13. the method as the corrosion of porous silicon of claim 12 is characterized in that corrosion is to carry out under 5～60 ℃ temperature.
Applications Claiming Priority (70)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP4221391 | 1991-02-15 | ||
| JP042213/91 | 1991-02-15 | ||
| JP042212/91 | 1991-02-15 | ||
| JP4221291 | 1991-02-15 | ||
| JP5560591 | 1991-02-28 | ||
| JP055602/91 | 1991-02-28 | ||
| JP5561191 | 1991-02-28 | ||
| JP5560291 | 1991-02-28 | ||
| JP055608/91 | 1991-02-28 | ||
| JP055612/91 | 1991-02-28 | ||
| JP5561491 | 1991-02-28 | ||
| JP5561291 | 1991-02-28 | ||
| JP5561091 | 1991-02-28 | ||
| JP055606/91 | 1991-02-28 | ||
| JP5560991 | 1991-02-28 | ||
| JP5561391 | 1991-02-28 | ||
| JP5560391 | 1991-02-28 | ||
| JP055611/91 | 1991-02-28 | ||
| JP055613/91 | 1991-02-28 | ||
| JP055604/91 | 1991-02-28 | ||
| JP055609/91 | 1991-02-28 | ||
| JP055601/91 | 1991-02-28 | ||
| JP5560891 | 1991-02-28 | ||
| JP055605/91 | 1991-02-28 | ||
| JP5560791 | 1991-02-28 | ||
| JP055603/91 | 1991-02-28 | ||
| JP055614/91 | 1991-02-28 | ||
| JP5560191 | 1991-02-28 | ||
| JP5560491 | 1991-02-28 | ||
| JP055607/91 | 1991-02-28 | ||
| JP5560691 | 1991-02-28 | ||
| JP055610/91 | 1991-02-28 | ||
| JP085755/91 | 1991-03-27 | ||
| JP8575591 | 1991-03-27 | ||
| JP148163/91 | 1991-05-24 | ||
| JP14816391 | 1991-05-24 | ||
| JP14816191 | 1991-05-24 | ||
| JP148160/91 | 1991-05-24 | ||
| JP148164/91 | 1991-05-24 | ||
| JP14816091 | 1991-05-24 | ||
| JP3148164A JPH04346418A (en) | 1991-05-24 | 1991-05-24 | Manufacture of semiconductor substrate |
| JP148161/91 | 1991-05-24 | ||
| JP149301/91 | 1991-05-27 | ||
| JP149302/91 | 1991-05-27 | ||
| JP149307/91 | 1991-05-27 | ||
| JP149311/91 | 1991-05-27 | ||
| JP149310/91 | 1991-05-27 | ||
| JP149308/91 | 1991-05-27 | ||
| JP149299/91 | 1991-05-27 | ||
| JP149297/91 | 1991-05-27 | ||
| JP149300/91 | 1991-05-27 | ||
| JP149306/91 | 1991-05-27 | ||
| JP149298/91 | 1991-05-27 | ||
| JP149309/91 | 1991-05-27 | ||
| JP150990/91 | 1991-05-28 | ||
| JP150982/91 | 1991-05-28 | ||
| JP150981/91 | 1991-05-28 | ||
| JP150980/91 | 1991-05-28 | ||
| JP150989/91 | 1991-05-28 | ||
| JP150983/91 | 1991-05-28 | ||
| JP150993/91 | 1991-05-28 | ||
| JP150992/91 | 1991-05-28 | ||
| JP150994/91 | 1991-05-28 | ||
| JP150985/91 | 1991-05-28 | ||
| JP150991/91 | 1991-05-28 | ||
| JP150984/91 | 1991-05-28 | ||
| JP152248/91 | 1991-05-29 | ||
| JP152249/91 | 1991-05-29 | ||
| JP152250/91 | 1991-05-29 | ||
| JP152251/91 | 1991-05-29 |
Related Child Applications (2)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN93118894A Division CN1099905A (en) | 1991-02-15 | 1993-10-08 | Production of semiconductor chip |
| CN 97105478 Division CN1099698C (en) | 1991-02-15 | 1997-06-02 | Method for making semiconductor substrate |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN1066748A CN1066748A (en) | 1992-12-02 |
| CN1037727C true CN1037727C (en) | 1998-03-11 |
Family
ID=27586500
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN92101589A Expired - Fee Related CN1037727C (en) | 1991-02-15 | 1992-02-15 | Etching liquid for etching porous silion, etching process use same and method making semiconductor substrate for such etching liquid |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN1037727C (en) |
Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP3250721B2 (en) * | 1995-12-12 | 2002-01-28 | キヤノン株式会社 | Method for manufacturing SOI substrate |
| CN1079450C (en) * | 1996-05-22 | 2002-02-20 | 中国科学技术大学 | Water thermal prepn. method for red, blue and ultraviolet ray emmitting porous silicon |
| CN102220643B (en) * | 2011-05-03 | 2013-03-27 | 浙江理工大学 | Wet method for passivating surface of germanium monocrystal |
| CN105154982A (en) * | 2015-07-08 | 2015-12-16 | 中国科学院宁波材料技术与工程研究所 | Polycrystalline black silicon texturization treatment fluid, polysilicon chip texturization method applying treatment fluid, and polycrystalline black silicon texturization product |
| CN115161032A (en) * | 2022-07-05 | 2022-10-11 | 北京师范大学 | Etching solution and method suitable for monocrystalline silicon wafer |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH02252265A (en) * | 1989-03-27 | 1990-10-11 | Sony Corp | Manufacture of semiconductor substrate |
-
1992
- 1992-02-15 CN CN92101589A patent/CN1037727C/en not_active Expired - Fee Related
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH02252265A (en) * | 1989-03-27 | 1990-10-11 | Sony Corp | Manufacture of semiconductor substrate |
Also Published As
| Publication number | Publication date |
|---|---|
| CN1066748A (en) | 1992-12-02 |
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