CN101866875A - A method for preparing SGOI material by layer transfer and ion implantation technology - Google Patents

Abstract

The invention relates to a method for preparing silicon germanium on insulator (SGOI) material. First epitaxial Si _1-x Ge _x /Si _epi /Si _1-y Ge _y structure multi-layer material on bulk silicon, where 0<x<1, 0<y<1, Si _1-x Ge _x is the epitaxial material of the upper surface. The thicknesses of the epitaxial Si _1-x Ge _x and Si _1-y Ge _y films are controlled to be less than the critical thickness, so as to ensure that the two films are fully strained. Then use layer transfer method to transfer Si _1-x Ge _x /Si/Si _1-y Ge _y to a support material with SiO ₂ /Si structure to form Si _1-y Ge _y /Si/Si _1-x Ge Multilayer material of _x /SiO ₂ /Si structure. Selective etching is used to remove Si _1-y Ge _y on the top layer, and finally through ion implantation and annealing, the Si _1-x Ge _x in the material is relaxed, and the corresponding top layer Si is strained to obtain Si/Si _1- SGOI material of _x Ge _x /SiO ₂ /Si.

Description

A kind of method of utilizing layer transfer and ion implantation technique to prepare the SGOI material

Technical field

The present invention relates to a kind of method for preparing germanium on insulator silicon (SGOI), a kind of more precisely method of utilizing layer transfer and ion implantation technique to prepare the SGOI material belongs to microelectronics and solid electronics technical field.

Background technology

Preparation smaller szie, more high performance device are the target and the direction of semi-conductor industry development always, along with development of semiconductor, rely on silicon materials can't prepare enough high speeds merely, the transistor of low-power consumption.From 90nm technology, strained silicon (sSi) technology and silicon-on-insulator (SOI) technology become the two big sharp weapon that promote Moore's Law.The strained-silicon-on-insulator technology that combines strained silicon and SOI technology now has been subjected to everybody pay attention to day by day, and it is considered to one of preferred substrate material of CMOS technology of future generation.

The strained-silicon-on-insulator material generally is divided into two kinds, and a kind of is that strained silicon materials directly is attached on the insulating barrier of silicon substrate, forms sSi/SiO ₂The sandwich structure of/Si (sSOI); Another kind is to also have one deck SiGe layer between strained silicon and the insulating barrier, forms sSi/SiGe/SiO ₂The four-layer structure of/Si (SGOI).Having of tensile stress is beneficial to the raising electron mobility among the sSOI, but the castering action to hole mobility is also not obvious, and SGOI is as a kind of double channel material, because the tensile stress in the strained silicon layer and the acting in conjunction of the compression in the SiGe layer, electronics and hole mobility in the material are improved simultaneously.

For preparation SGOI material, existing class known method report, comparatively typical method can be published in the article of the 48th volume the 8th phase 1297-1305 page or leaf of Solid-State Electronics with reference to people such as Taraschi in 2004, exercise question is " Strained Si; SiGe, and Ge on-insulator:reviewof wafer bonding fabrication techniques ".In this piece article, introduced and used layer to shift the method for preparing the SGOI material.In described method, extension relaxation SiGe material at first, then with the SiGe material transfer of relaxation to SiO ₂On the support substrates of/Si structure.For extension relaxation S iGe material, need earlier the graded buffer layer of several microns of on body silicon extensions, material epitaxy often needs the times several even tens hours.

For this reason, the present invention plans to introduce a kind of new method of the SGOI of preparation material.At first prepare the strain SiGe material, transfer to SiO at strain gauge material ₂After on the support substrates of/Si structure, make its relaxation, not only make the shortening of material epitaxy time but also prepared material property is improved by ion injection and annealing process.

Summary of the invention

The object of the present invention is to provide a kind of method of the SGOI of preparation material.Comprise the steps: at first (Si on the body silicon substrate _Sub) the method epitaxy Si successively of using chemical vapour deposition (CVD) _1-yGe _y, Si _Epi, Si _1-xGe _xThree kinds of different films, wherein 0＜x＜1,0＜y＜1.According to x in the epitaxial material, the difference of y value, the Si of selective epitaxy _1-yGe _y, Si _1-xGe _xThe thickness of film, make it all less than critical thickness, (study now and experiment has been found that, on the Si substrate in the epitaxy Si Ge film, there is a critical thickness, when the SiGe of extension film thickness less than this critical thickness the time, the SiGe material is complete strain, and this critical thickness reduces with the increase of the component of Ge in the SiGe material.The pass of critical thickness and Ge component x is h _c≈ 0.0234/ (1+0.04x) ²* ln (h _c/ 4)), for Si _1-yGe _y, Si _1-xGe _xBetween the Si of extension _EpiIt then can be any thickness.After extension is finished, obtain Si _1-xGe _x/ Si _Epi/ Si _1-yGe _y/ Si _SubThe multilayer material of structure, Si _1-xGe _xBe the upper surface of epitaxial material, Si _EpiBe the Si of extension, Si _SubBe the substrate silicon material.This material has been prepared SiO with another sheet surface ₂Si backing material bonding, obtain Si _Sub/ Si _1-yGe _y/ Si _Epi/ Si _1-xGe _x/ SiO ₂The multilayer material of/Si structure.By abrasive method, remove Si _Sub, obtain Si _1-yGe _y/ Si _Epi/ Si _1-xGe _x/ SiO ₂The material of/Si structure.Si wherein _1-yGe _yThe Si that may also have part above _Sub, select first kind of suitable chemical solution, adopt the method for selective corrosion, remove Si _1-yGe _yThe Si that exists above _Sub, corrosion stops at Si _1-yGe _yOn the surface.Select second kind of suitable chemical solution then, adopt the method for selective corrosion, erode remaining Si _1-yGe _y, corrosion stops at Si _EpiOn the material, promptly obtain Si _Epi/ Si _1-xGe _x/ SiO ₂/ Si material.Use is than low dosage (1 * 10 ¹⁵Cm ^-2～3 * 10 ¹⁶Cm ^-2) H ⁺, He ⁺Perhaps other ions are injected into Si _1-xGe _x/ SiO ₂On the interface of material, perhaps be injected into SiO ₂Close Si in the material _1-xGe _xThe place, under 700～1100 ℃ of temperature, anneal, on the one hand increase bond strength, make Si on the other hand _1-xGe _xMaterial generation relaxation has finally formed the SGOI material.Or by grinding or lithographic method removes Si earlier _EpiLayer, and then inject and annealing, then need at Si _1-xGe _xThe Si thin layer that extension one deck is new on the material (seeing embodiment 1 for details).Need the resilient coating of several microns of extensions even tens microns with respect to conventional method, using the present invention to prepare SGOI only needs film about extension 0.1-0.5 micron, can save the extension time greatly, reduces cost.

In a preferred embodiment, extension is prepared Si _1-xGe _x/ Si _Epi/ Si _1-yGe _y/ Si _SubBehind the multilayer material of structure, with the H of doses ⁺Perhaps He ⁺Ion is injected into Si _1-yGe _yIn the material, prepared SiO with another sheet surface then ₂Si backing material bonding, form Si _Sub/ Si _1-yGe _y/ Si _Epi/ Si _1-xGe _x/ SiO ₂The multilayer material of/Si structure.This material is annealed under 400～600 ℃ of temperature, make material at H ⁺Perhaps He ⁺Genetic horizon separated near ion injected range, obtained Si _1-yGe _y/ Si/Si _1-xGe _x/ SiO ₂The material of/Si structure.Select suitable chemical solution, adopt the method for selective corrosion, erode remaining Si _1-yGe _y, corrosion stops at Si _EpiOn the material, promptly obtain Si _Epi/ Si _1-xGe _x/ SiO ₂/ Si material.Use is than low dosage (10 ¹⁵Cm ^-210 ¹⁶Cm ^-2) H ⁺, He ⁺Perhaps other ions are injected into Si _1-xGe _x/ SiO ₂On the interface of material, perhaps be injected into SiO ₂Close Si in the material _1-xGe _xThe place, under 700～1100 ℃ of temperature, anneal, on the one hand increase bond strength, make Si on the other hand _1-xGe _xMaterial generation relaxation has finally formed the SGOI material, or removes Si earlier by grinding or lithographic method _EpiLayer, and then inject and annealing, then need at Si _1-xGe _xThe Si thin layer that extension one deck is new on the material (seeing embodiment 2 for details).

Description of drawings

Fig. 1 is an epitaxy Si on the body silicon substrate that the present invention relates to _1-yGe _y, Si _Epi, Si _1-xGe _xSchematic cross-section, 1 is the body silicon substrate, 2 is Si _1-yGe _yLayer, 3 is Si _EpiLayer, 4 is Si _1-xGe _xLayer.

To be the epitaxial material that the present invention relates to carry out schematic cross-section behind the bonding with the support substrates material to Fig. 2.5 is SiO ₂Layer, 6 for supporting layer-of-substrate silicon.

Fig. 3 is the material section schematic diagram after the grinding of the present invention relates to.

Fig. 4 material section schematic diagram after the selective corrosion that has been the carrying out that the present invention relates to.

Fig. 5 is the material section schematic diagram of the SGOI that the present invention relates to.7 for upper surface has produced the silicon layer of strain, and 8 is H ⁺, He ⁺Ion implanted region.

Fig. 6 is the H that the present invention relates to ⁺Perhaps He ⁺With 5 * 10 ¹⁶Cm ^-2～1 * 10 ¹⁷Cm ^-2Dosage be injected into material section schematic diagram behind the epitaxial film.9 for injecting H ⁺Perhaps He ⁺Accumulation regions.

Embodiment

The following example will help to understand the present invention, but not limit content of the present invention.

Execution mode 1

1, the method for on the body silicon substrate, using chemical vapour deposition (CVD) epitaxy Si successively _1-yGe _y, Si _Epi, Si _1-xGe _xThree kinds of different films, wherein 0＜x＜1,0＜y＜1.According to x in the epitaxial material, the difference of y value, the Si of selective epitaxy _1-yGe _y, Si _1-xGe _xThe thickness of film makes it all less than critical thickness, for Si _1-yGe _y, Si _1-xGe _xBetween the Si of extension _EpiThen can be any thickness, the preferable range of x be 0＜x≤0.30, and the preferable range of y is 0＜y≤0.20, and as an optimal value, x is 0.25, and y is 0.15 (seeing accompanying drawing 1).

2, get the silicon substrate material of another sheet, by thermal oxidation, perhaps plasma enhanced chemical vapor deposition (PECVD), perhaps additive method is prepared SiO in surface of silicon ₂, SiO ₂Thickness is generally at 200nm～1um.

3, the material that step 1 is prepared is with the material bonding (seeing accompanying drawing 2) of step 2 preparation.

4, pass through abrasive method, the material that step 3 is obtained removes body silicon Si, using described first kind of chemical solution is the chemical solution that comprises TMAH (Tetramethyl ammonium hydroxide tetramethyl aqua ammonia) or KOH solution, surperficial remaining Si is fallen in selective corrosion, and etching stopping is at Si _1-yGe _yLayer (seeing accompanying drawing 3).

5, use described second kind of chemical solution to be HNO for comprising volume proportion ₃: H ₂O: HF (0.5%)=40: 20: 5 is at interior chemical solution (HF (0.5%) expression water: HF=200 wherein: 1) etch away the remaining Si of step 4 _1-yGe _yLayer, corrasion stops at Si _Epi(see accompanying drawing 4) on the epitaxial loayer.

6, use H ⁺, He ⁺Perhaps other ions are with 1 * 10 ¹⁵Cm ^-2～3 * 10 ¹⁶Cm ^-2Dosage be injected into Si _1-xGe _x/ SiO ₂On the interface of material, perhaps be injected into SiO ₂In near Si _1-xGe _xThe place, under 700～1100 ℃ of temperature, anneal, on the one hand increase bond strength, make Si on the other hand _1-xGe _xMaterial generation relaxation, corresponding Si _1-xGe _xSi above the material _EpiThe preparation of SGOI material is finished in the material production strain.Wherein, preferably injecting ion is H ⁺Perhaps He ⁺, preferred implantation dosage is 1 * 10 ¹⁶m ^-2(seeing accompanying drawing 5).

If 7 grindings of using after step 5 or lithographic method have removed Si _EpiLayer, the method by chemical vapour deposition (CVD) then is at the Si of step 6 relaxation _1-xGe _xThe Si thin layer that top extension one deck is new is because this layer is at Si _1-xGe _xLast extension, the Si layer will keep tensile strain.

Execution mode 2

1, the method for on the body silicon substrate, using chemical vapour deposition (CVD) epitaxy Si successively _1-yGe _y, Si _Epi, Si _1-xGe _xThree kinds of different films, wherein 0＜x＜1,0＜y＜1.According to x in the epitaxial material, the difference of y value, the Si of selective epitaxy _1-yGe _y, Si _1-xGe _xThe thickness of film makes it all less than critical thickness, for Si _1-yGe _y, Si _1-xGe _xBetween the Si of extension _EpiThen can be any thickness (seeing accompanying drawing 1), the preferable range of x be 0＜x≤0.30, and the preferable range of y is 0＜y≤0.20, and as an optimal value, x is 0.25, and y is 0.15.

2, with H ⁺Perhaps He ⁺With 5 * 10 ¹⁶Cm ^-2～1 * 10 ¹⁷Cm ^-2Dosage, select suitable energy, be injected into the Si of epitaxial material from the upper surface of the material of step 1 preparation _1-yGe _yIn the layer (seeing accompanying drawing 6), as a preferred value, H ⁺Or He ⁺Implantation dosage is 6 * 10 ¹⁶Cm ^-2

3, get the new silicon substrate material of a slice, by comprising thermal oxidation.Perhaps plasma enhanced chemical vapor deposition (PECVD) is prepared SiO in interior method in surface of silicon ₂, SiO ₂Thickness is generally at 200nm～1um.

4, the material that step 2 is prepared is with the material bonding of step 3 preparation.

5, the material that step 4 is obtained is annealed under 400～600 ℃ of temperature, makes material at H ⁺Perhaps He ⁺Genetic horizon separated near ion injected range.

6, use volume proportion to be HNO ₃: H ₂Chemical solution or other the high SiGe of O: HF (0.5%)=40: 20: 5: the chemical solution of Si etching ratio etches away the remaining Si of step 5 as selective corrosion solution _1-yGe _yLayer, corrasion stops at Si _EpiOn the epitaxial loayer.

7, use H ⁺, He ⁺Perhaps other ions are with 1 * 10 ¹⁵Cm ^-2～3 * 10 ¹⁶Cm ^-2Dosage be injected into Si _1-xGe _x/ SiO ₂On the interface of material, perhaps be injected into SiO ₂In near Si _1-xGe _xThe place, under 700～1100 ℃ of temperature, anneal, on the one hand increase bond strength, make Si on the other hand _1-xGe _xMaterial generation relaxation, corresponding Si _1-xGe _xSi above the material _EpiThe preparation of SGOI material is finished in the material production strain.In this technology, preferably injecting ion is H ⁺Perhaps He ⁺, preferred implantation dosage is 1 * 10 ¹⁶Cm ^-2

If 8 have removed Si with grinding or lithographic method after step 6 _EpiLayer, the method by chemical vapour deposition (CVD) then is at the Si of step 7 relaxation _1-xGe _xThe Si thin layer that top extension one deck is new is because this layer is at Si _1-xGe _xLast extension, the Si layer will keep tensile strain.

Claims (7)

1. a method utilizing layer transfer and ion implantation technology to prepare SGOI material is characterized in that adopting any one of following A or B two methods: Method A ① Three different thin films of Si _1-y Ge _y , Si _epi , and Si _1-x Ge _x are epitaxy sequentially on the silicon substrate by chemical vapor deposition, where 0<x<1, 0<y<1, According to the different values of x and y in the epitaxial material, the thickness of the epitaxial Si _1-y Ge _y , Si _1-x Ge _x films is selected so that they are all less than the critical thickness; while Si _1-y Ge _y , Si _1-x The thickness of the epitaxial Si _epi layer between Ge _x is any thickness; after the epitaxy is completed, a multilayer material of Si _1-x Ge _x /Si _epi /Si _1-y Ge _y /Si _sub structure is obtained, Si _1-x Ge _x is the upper surface of the epitaxial material, Si _epi is the epitaxial Si, and Si _sub is the substrate silicon material; ② Bond the multilayer material prepared in step 1 with another silicon substrate material on which SiO ₂ has been prepared on the surface to obtain Si _sub /Si _1-y Ge _y /Si _epi /Si _1-x Ge _x /SiO ₂ / Multilayer material with Si structure; ③Remove Si _sub by grinding method to obtain Si _1-y Ge _y /Si _epi /Si _1-x Ge _x /SiO ₂ /Si structure material, and use selective etching method to remove Si _1-y Ge _y The presence of Si _sub above makes the corrosion stop on the surface of Si _1-y Ge _y ; ④ Then select a chemical solution and use a selective etching method to etch away Si _1-y Ge _y to stop the corrosion on the Si _epi material, that is, to obtain Si _epi /Si _1-x Ge _x /SiO ₂ /Si material; ⑤Using 1×10 ¹⁵ cm ^-2 ~ 3×10 ¹⁶ cm ^-2 low-dose H ⁺ or He ⁺ ions implanted on the interface of Si _1-x Ge _x /SiO ₂ material, or implanted into SiO ₂ material close to For Si _1-x Ge _x , annealing is carried out at a temperature of 700-1100°C to increase the bonding strength and at the same time make the Si _1-x Ge _x material relax, and the corresponding Si _epi on the Si _1-x Ge _x material The material is strained, eventually forming the SGOI material; Method B ① Three different thin films of Si _1-y Ge _y , Si _epi , and Si _1-x Ge _x are epitaxy sequentially by chemical vapor deposition on bulk silicon substrate Si _sub , where 0<x<1, 0<y< 1. According to the different values of x and y in the epitaxial material, the thickness of the epitaxial Si _1-y Ge _y and Si _1-x Ge _x films is selected so that they are all less than the critical thickness; while Si _1-y Ge _y and Si ₁ The thickness of the epitaxial Si _epi layer between _-x Ge _x is arbitrary thickness; after the epitaxy is completed, a multilayer material of Si _1-x Ge _x /Si _epi /Si _1-y Ge _y /Si _sub structure is obtained, Si _{1- x} Ge _x is the upper surface of the epitaxial material, Si _epi is the epitaxial Si, and Si _sub is the substrate silicon material; ② After epitaxially preparing a multilayer material with Si _1-x Ge _x /Si _epi /Si _1-y Ge _y /Si _sub structure, apply a low dose of 5×10 ¹⁶ cm ^-2 to 1×10 ¹⁷ cm ^-2 The H ⁺ or He ⁺ ions are implanted into the Si _1-y Ge _y material; ③ Then bond with another silicon substrate material whose surface has been prepared with SiO ₂ to form a multilayer material with Si _sub /Si _1-y Ge _y /Si _epi /Si _1-x G _x /SiO ₂ /Si structure; ④ Anneal the multi-layer material prepared in step 2 at a temperature of 400-600°C, so that the layer separation of the material occurs near the range of H ⁺ or He ⁺ ion implantation, and Si _1-y Ge _y /Si/Si _1-x Ge _x is obtained /SiO ₂ /Si structure material; ⑤Choose a chemical solution and use a selective etching method to etch away the remaining Si _1-y Ge _y , so that the corrosion stops on the Si _epi material, that is, the Si _epi /Si _1-x Ge _x /SiO ₂ /Si material is obtained; ⑥ Implant H ⁺ or He ⁺ ions at a dose of 1×10 ¹⁵ cm ^-2 to 3×10 ¹⁶ cm ^-2 to the interface of Si _1-x Ge _x /SiO ₂ material, or implant it into SiO ₂ material close to At the Si _1-x Ge _x place, annealing is carried out at a temperature of 700-1100 ° C, which increases the bonding strength and relaxes the Si _1-x Ge _x material, and the Si _epi material on the corresponding Si _1-x Ge _x material undergoes strain, eventually forming the SGOI material. 2. The preparation method according to claim 1, characterized in that in method A or method B, 0<x0.30, 0<y≤0.25. 3. according to the described preparation method of claim 2, it is characterized in that x=0.25, y=0.15 in method A or method B. 4. according to the described preparation method of claim 1, it is characterized in that the _SiO on the surface of another silicon substrate material in method A or B is prepared by thermal oxidation or plasma enhanced chemical vapor deposition method, and the thickness is 200nm-1 μm . 5. by the described preparation method of claim 1, it is characterized in that: ① After step 4 of method A, the Si _epi layer is removed by grinding or etching, and then a new Si thin layer is epitaxially grown on the relaxed Si _1-x Ge _x in step 5 by chemical vapor deposition, Si The thin layer will maintain tensile strain; ② After step 5 of method B, the Si _epi layer is removed by grinding or etching, and then a new Si thin layer is epitaxially grown on the relaxed Si _1-x Ge _x in step 6 by chemical vapor deposition, Si The thin layer will maintain tensile strain. 6. by the described preparation method of claim 1, it is characterized in that: ① In step 3 of method A, a chemical solution including TMAH or KOH solution is used to selectively etch the substrate silicon material; ② The selective chemical solution described in step 4 of method A and step 5 of method B includes a chemical solution with a volume ratio of HNO ₃ : H ₂ O : 0.5% HF=40:20:5 as a selective etching solution, wherein 0.5% HF means water:HF=200:1. 7. by the described preparation method of claim 1, it is characterized in that: ① The injection dose of H ⁺ or He ⁺ in step 5 of method A is 1×10 ¹⁶ cm ^-2 ; ②In step 2 of method B, the injection dose of H ⁺ or He ⁺ is 6×10 ¹⁶ cm ^-2 ; ③ The injection dose of H ⁺ or He ⁺ in step 6 of method B is 1×10 ¹⁶ cm ^-2 .

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