CN101158026A - Method for growing ultra-thin NbN superconducting film on MgO or Si substrate - Google Patents
Method for growing ultra-thin NbN superconducting film on MgO or Si substrate Download PDFInfo
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- CN101158026A CN101158026A CNA2007101322835A CN200710132283A CN101158026A CN 101158026 A CN101158026 A CN 101158026A CN A2007101322835 A CNA2007101322835 A CN A2007101322835A CN 200710132283 A CN200710132283 A CN 200710132283A CN 101158026 A CN101158026 A CN 101158026A
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- 239000000758 substrate Substances 0.000 title claims abstract description 35
- 238000000034 method Methods 0.000 title claims abstract description 16
- 238000004140 cleaning Methods 0.000 claims abstract description 8
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims abstract description 7
- 229910052814 silicon oxide Inorganic materials 0.000 claims abstract description 7
- 239000010408 film Substances 0.000 claims description 39
- 239000010409 thin film Substances 0.000 claims description 15
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Chemical compound O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 6
- CSCPPACGZOOCGX-UHFFFAOYSA-N Acetone Chemical compound CC(C)=O CSCPPACGZOOCGX-UHFFFAOYSA-N 0.000 claims description 4
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 claims description 4
- 238000004544 sputter deposition Methods 0.000 claims description 4
- 230000001133 acceleration Effects 0.000 claims description 2
- 238000001816 cooling Methods 0.000 claims description 2
- 239000008367 deionised water Substances 0.000 claims description 2
- 229910021641 deionized water Inorganic materials 0.000 claims description 2
- 239000012530 fluid Substances 0.000 claims description 2
- 239000007789 gas Substances 0.000 claims description 2
- 229910052757 nitrogen Inorganic materials 0.000 claims description 2
- 230000002000 scavenging effect Effects 0.000 claims description 2
- 238000004062 sedimentation Methods 0.000 claims description 2
- 238000004506 ultrasonic cleaning Methods 0.000 claims description 2
- 238000005516 engineering process Methods 0.000 abstract description 5
- 238000001755 magnetron sputter deposition Methods 0.000 abstract description 4
- 239000000498 cooling water Substances 0.000 abstract 1
- 239000013078 crystal Substances 0.000 abstract 1
- 238000000280 densification Methods 0.000 abstract 1
- 238000000407 epitaxy Methods 0.000 abstract 1
- 238000010884 ion-beam technique Methods 0.000 abstract 1
- 229910021421 monocrystalline silicon Inorganic materials 0.000 abstract 1
- 230000007704 transition Effects 0.000 description 8
- 238000004458 analytical method Methods 0.000 description 4
- 238000001514 detection method Methods 0.000 description 4
- 239000002784 hot electron Substances 0.000 description 3
- 238000002360 preparation method Methods 0.000 description 3
- 238000002441 X-ray diffraction Methods 0.000 description 2
- 238000003780 insertion Methods 0.000 description 2
- 230000037431 insertion Effects 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 238000011160 research Methods 0.000 description 2
- 229910004298 SiO 2 Inorganic materials 0.000 description 1
- 238000003917 TEM image Methods 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000005540 biological transmission Effects 0.000 description 1
- 229910021419 crystalline silicon Inorganic materials 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 238000002003 electron diffraction Methods 0.000 description 1
- 230000001590 oxidative effect Effects 0.000 description 1
- 230000000704 physical effect Effects 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 230000035945 sensitivity Effects 0.000 description 1
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Abstract
The invention provides a growing method of an ultra-thin NbN superconducting film on the MgO or Si substrate, which comprises that (a) the single crystal substrate of MgO or Si or SiOx / Si is cleaned; (b) when the substrate is put into a sample seat of a magnetron sputtering system, the sample seat is cooled through circulating cooling water, of which temperature is below 20 DEG C; (c) the system is vacuumized, then the substrate is cleaned by using an ion beam cleaning technology; (d) after the cleaning, the system continues to vacuumize; (e) NbN films grows sputteringly. The study of XRD, AFM and TEM confirms the epitaxy of films, as well as the densification and continuity of film growth. A SiOx layer in the Si substrate contributes to strengthen the superconducting power of the ultra-thin NbN superconducting film. Compared with the pure single crystal Si substrate, the Tc and Jc of the ultra-thin NbN superconducting film that grows on the system are higher.
Description
Technical field
The present invention relates to a kind of superconduction ultrathin film preparation methods, particularly a kind of on MgO or Si substrate the growth method of ultra-thin NbN superconducting thin film.
Background technology
In the nearly more than ten years, because the high speed development of film preparing technology and Micrometer-Nanometer Processing Technology, promoted the superconduction hot-electron device to develop rapidly greatly, for example, be applied to the superconduction thermoelectron frequency mixer (HEM) in Terahertz high-end (1-8THz) detection technique, show superconducting single-photon detection means (SSPD) of excellent performance or the like in using near infrared, infrared and visible light frequency band.These superconductive devices are based on the technology of the superconducting thin film of ultrafine several nano thickness, and have submicron and nano level device size.For the HEM device, the superconducting transition temperature Tc of ultrathin film, critical current density jc have determined the detection performance index of device, and high Tc and Jc can obtain high intermediate frequency (IF) gain bandwidth, and the required intrinsic power of mixing is relative also lower.For the SSPD device, high Tc and Jc can promote detection sensitivity and speed.Thereby high-quality superconduction ultrathin film is the basis of superconduction hot-electron device.
Superconduction NbN material has higher working temperature (more than the 10K) and higher operating frequency (1.4THz), is the main preparation material of using in the research of THz frequency range hot-electron device at present; Be operated in the HEB detector of 1～6THz frequency range, adopt the ultra-thin NbN film of several nanometer thickness to make usually.
Summary of the invention
Goal of the invention: the purpose of this invention is to provide a kind of high quality, high performance on MgO or Si substrate the growth method of ultra-thin NbN superconducting thin film.
Technical scheme: of the present invention a kind of on MgO or Si substrate the method for the NbN superconducting thin film of grow ultra-thin, may further comprise the steps:
(a) cleaning of MgO or Si or SiOx/Si monocrystal chip: substrate is put into acetone and spirituous solution ultrasonic cleaning (each 5 minutes approximately time), use deionized water rinsing (about 10 minutes of time) then, nitrogen dries up, and is standby; Wherein x is 1 or 2;
(b) substrate is put on the specimen holder of magnetic control sputtering system, specimen holder adopts cooling circulating water to cool off, and water temp is lower than 20 degree Celsius;
(c) vacuum system of being made up of molecular pump and mechanical pump vacuumizes, when vacuum chamber background vacuum less than 5 * 10
-4Behind the Pa, utilize the ionic fluid cleaning technique to clean substrate;
The ion cleaning condition is; Voltage 300eV, line 30mA, acceleration voltage 220V, scavenging period 3 minutes;
(d) clean end, system continues to be evacuated to the background vacuum less than 3 * 10
-5Pa;
(e) sputter growth NbN film.
Growth gasses is Ar:N
2Mixed gas, ratio 4-6: 1 (mass ratio), operating air pressure 0.27-0.7Pa; Adopt d.c. sputtering, power density is 4.5W/cm
2, sedimentation rate is 700nm/min.
Beneficial effect: the present invention utilizes magnetron sputtering technique, on MgO (100) substrate, successfully prepared epitaxially grown ultra-thin NbN superconducting thin film, when the NbN film thickness is 6nm, its superconducting transition temperature is up to 14.46K, width of transition 0.21K, at the NbN film thickness only about 1nm, superconducting transition temperature is also up to 3.5K during promptly about 2 atomic layer level thickness.The superconducting critical current density of the ultra-thin NbN film of growing on MgO (100) substrate can both reach 10
7A/cm
2Magnitude; On Si (100) and SiOx/Si substrate, prepared the ultra-thin NbN superconducting thin film of polycrystalline, the NbN film of 6nm thickness, transition temperature is respectively 8.74K and 9.2K, and width of transition is respectively 0.42K and 0.45K, and current density has reached 10
6A/cm
2Magnitude.XRD, AFM, TEM research have confirmed the extension performance of film and the continuity and the compactness of film growth.The on-chip SiOx layer of Si helps to improve the superconductive power of ultra-thin NbN superconducting thin film, compares with simple single crystalline Si substrate, and the Tc and the Jc of the ultra-thin NbN superconducting thin film of growth are higher on it.
Description of drawings
Fig. 1 is NbN/MgO film (～6nm) an afm image.
Fig. 2 is NbN/Si film (～6nm) an afm image.
Fig. 3 (a) is a NbN/MgO interface enlarged image, and the little figure of insertion is the TEM image K-M of NbN; (b) be NbN/Si interface enlarged image.
Embodiment
The present invention utilizes conventional magnetron sputtering technique, the ultra-thin NbN film of the different thickness of on monocrystalline MgO (100), Si (100) and SiOx/Si (x is 1 or 2) substrate, successfully having grown, and thickness range does not wait to 8 nanometers from book 1 nanometer.The film growth condition is as follows.
The crystalline structure of structure and electric property: MgO and NbN is similar, all is face-centered cubic.The lattice parameter of MgO is 0.421 nanometer, and the NbN lattice parameter is 0.446 nanometer, and both lattice degree of excuse me, but I must be leaving now are 5%.Adopt the magnetron sputtering technique of optimizing on monocrystalline MgO substrate, to grow the NbN film of extension.Si can only obtain polycrystalline NbN film owing to bigger with the NbN lattice mismatch on the Si substrate.The electric property of these ultra-thin NbN films is very outstanding.Superconducting transition temperature and superconducting critical current density are respectively as shown in Table 1.
The film growth condition
| The background vacuum | ＜2.5×10 -5PA |
| Target | Nb(99.999％) |
| Ar∶N 2(quality) | 4-6∶1 |
| Operating air pressure | 0.27-0.7Pa |
| Working current | 0.9A |
| Operating voltage | ～410V |
| Underlayer temperature | Water-cooled |
| Sputter rate | ～700/min |
NbN ultrathin film on the MgO substrate
| The NbN film thickness | Tc(/K) | ΔT(/K) | Jc(A/cm 2) |
| 8nm | 14.6 | 0.2 | 2.5×10 7 |
| 6nm | 14.46 | 0.21 | 2.08×10 7 |
| 4nm | 13.8 | 0.26 | 1.8×10 7 |
| 2.7nm | 13.2 | 0.58 | 1.35×10 7 |
| 1.3nm | 11.4 | 1 | 1×10 7 |
| 0.9nm | 3.5 | 1.2 |
NbN ultrathin film on the Si substrate
| The NbN film thickness | Tc(/K) | ΔT(/K) | Jc(A/cm 2) |
| 6nm | 8.75 | 0.42 | 1.5×10 6 |
| 4nm | 6.8 | 0.45 | 0.8×10 6 |
| 2.7nm | 3.75 | 0.77 | 0.5×10 5 |
SiO
2NbN ultrathin film on the/Si substrate
| The NbN film thickness | Tc(/K) | ΔT(/K) | Jc(A/cm 2) |
| 6nm | 9.2 | 0.45 | 1.5×10 6 |
| 4nm | 7.6 | 0.7 | 0.9×10 6 |
| 2.7nm | 6.9 | 0.77 | 0.9×10 6 |
| 1.3nm | 4 | 1.1 | 0.5×10 5 |
The AFM of ultra-thin NbN film analyzes: utilize the modern analysis means: X-ray diffraction (XRD), transmission electron microscope (TEM), atomic force microscope technical Analysis such as (AFM) have been studied physical propertys such as the microtexture, thickness, surface interface situation of prepared ultra-thin NbN film.
It is the ultra-thin NbN film sample of having grown 5 seconds that AFM has analyzed, according to growth for Thin Film speed, and the about 5.5～6nm of estimated thickness.Fig. 1 and Fig. 2 are divided into the afm image of thick NbN/MgO of about 6nm (100) and NbN/Si (100) film, in the zone of 5 * 5 μ m, its r.m.s. roughness only is 0.435nm and 0.377nm, and in the zone of about 1 * 1 μ m (among the figure in the white box), its r.m.s. roughness only is 0.190nm and 0.121nm.
Above-mentioned AFM result illustrates that the NbN ultrathin film for preparing is very fine and close and successive on MgO (100) and Si (100) substrate, the planeness on surface is fine; And the NbN film of growing on the Si substrate, compared with the film of growing on the MgO substrate, surface finish is better.
The tem analysis of ultra-thin NbN film: NbN/MgO (100) and NbN/Si (100) ultrathin film to preparation have been done tem analysis.Among Fig. 3 (a), NbN does not have tangible transition layer along the lattice continued growth of MgO; Insertion figure among Fig. 3 (a) is the electron diffraction photo of NbN film, and diffraction spot is very sharp keen, clear, and is arranged in square lattice, does not have diffraction ring to occur, and proves that our prepared NbN/MgO (100) ultrathin film is a monocrystal thin films.Among Fig. 3 (b), the NbN film is close grain polycrystalline situation, the thick natural oxidizing layer of 1.5nm of having an appointment between NbN and the Si substrate.From two photos as can be seen; The planeness at the interface between Si and the NbN obviously is better than the planeness at interface between MgO and the NbN.
Claims (4)
1. the method for the NbN superconducting thin film of grow ultra-thin on MgO or Si substrate is characterized in that this method may further comprise the steps:
(a) cleaning of MgO or Si or SiOx/Si monocrystal chip: substrate is put into acetone and spirituous solution ultrasonic cleaning, use deionized water rinsing then, nitrogen dries up, and is standby; Wherein x is 1 or 2;
(b) substrate is put on the specimen holder of magnetic control sputtering system, specimen holder adopts cooling circulating water to cool off, and water temp is lower than 20 degree Celsius;
(c) vacuum system of being made up of molecular pump and mechanical pump vacuumizes, when vacuum chamber background vacuum less than 5 * 10
-4Behind the Pa, utilize the ionic fluid cleaning technique to clean substrate;
(d) clean end, system continues to be evacuated to the background vacuum less than 3 * 10
-5Pa;
(e) sputter growth NbN film.
2. according to claim 1 on MgO or Si substrate the method for the NbN superconducting thin film of grow ultra-thin, it is characterized in that the ion cleaning condition is in the step (c); Voltage 300eV, line 30mA, acceleration voltage 220V, scavenging period 3 minutes.
3. according to claim 1 on MgO or Si substrate the method for the NbN superconducting thin film of grow ultra-thin, it is characterized in that in the step (e), growth gasses is Ar:N
2Mixed gas, mass ratio is 4-6: 1, operating air pressure 0.27～0.7Pa.
4. according to claim 1 on MgO or Si substrate the method for the NbN superconducting thin film of grow ultra-thin, it is characterized in that in the step (e) that adopt d.c. sputtering, power density is 4.5W/cm
2, sedimentation rate is 700mm/min.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNA2007101322835A CN101158026A (en) | 2007-09-13 | 2007-09-13 | Method for growing ultra-thin NbN superconducting film on MgO or Si substrate |
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|---|---|---|---|
| CNA2007101322835A CN101158026A (en) | 2007-09-13 | 2007-09-13 | Method for growing ultra-thin NbN superconducting film on MgO or Si substrate |
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| CN101158026A true CN101158026A (en) | 2008-04-09 |
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Cited By (10)
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|---|---|---|---|---|
| CN101775589A (en) * | 2010-03-25 | 2010-07-14 | 西安交通大学 | Preparation method of surface conduction electron-emitter film with Nb-Si-N nanometer bi-phase structure |
| CN102534471A (en) * | 2010-12-07 | 2012-07-04 | 北京有色金属研究总院 | Method for preparing FeSe superconducting thin film by post-selenization treatment |
| CN102867907A (en) * | 2012-10-11 | 2013-01-09 | 南京大学 | Method for manufacturing soft superconducting thin film |
| CN103165811A (en) * | 2013-02-25 | 2013-06-19 | 苏州大学 | Silicon substrate niobium nitride film superconducting material and preparing method thereof |
| CN103276365A (en) * | 2013-05-22 | 2013-09-04 | 南京大学 | Method for optimizing superconducting performance of niobium nitride film on silicon substrate by using buffer layer |
| CN105449094A (en) * | 2015-12-29 | 2016-03-30 | 中国科学院上海微系统与信息技术研究所 | Preparation method of NbN thin film, SQUID device and preparation method of SQUID device |
| CN108588653A (en) * | 2018-02-07 | 2018-09-28 | 中国科学院紫金山天文台 | The method for preparing titanium nitride superconducting thin film on a silicon substrate using magnetron sputtering method |
| CN114774868A (en) * | 2022-03-31 | 2022-07-22 | 南京大学 | Method for depositing niobium nitride on diamond based on ion polishing technology |
| CN116377407A (en) * | 2023-04-03 | 2023-07-04 | 之江实验室 | Low-stress NbN superconducting film and preparation method and application thereof |
| CN117070892A (en) * | 2023-08-10 | 2023-11-17 | 之江实验室 | Two-step control N 2 Method for reducing internal stress of NbN film and improving superconducting transition temperature by partial pressure |
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2007
- 2007-09-13 CN CNA2007101322835A patent/CN101158026A/en active Pending
Cited By (16)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101775589A (en) * | 2010-03-25 | 2010-07-14 | 西安交通大学 | Preparation method of surface conduction electron-emitter film with Nb-Si-N nanometer bi-phase structure |
| CN102534471A (en) * | 2010-12-07 | 2012-07-04 | 北京有色金属研究总院 | Method for preparing FeSe superconducting thin film by post-selenization treatment |
| CN102534471B (en) * | 2010-12-07 | 2013-06-19 | 北京有色金属研究总院 | Method for preparing FeSe superconducting thin film by post-selenization treatment |
| CN102867907A (en) * | 2012-10-11 | 2013-01-09 | 南京大学 | Method for manufacturing soft superconducting thin film |
| CN102867907B (en) * | 2012-10-11 | 2016-09-21 | 南京大学 | A kind of method preparing flexible superconducting thin film |
| CN103165811B (en) * | 2013-02-25 | 2016-04-20 | 苏州大学 | A kind of silica-based niobium nitride film superconductor and preparation method thereof |
| CN103165811A (en) * | 2013-02-25 | 2013-06-19 | 苏州大学 | Silicon substrate niobium nitride film superconducting material and preparing method thereof |
| CN103276365B (en) * | 2013-05-22 | 2015-07-08 | 南京大学 | Method for optimizing superconducting performance of niobium nitride film on silicon substrate by using buffer layer |
| CN103276365A (en) * | 2013-05-22 | 2013-09-04 | 南京大学 | Method for optimizing superconducting performance of niobium nitride film on silicon substrate by using buffer layer |
| CN105449094A (en) * | 2015-12-29 | 2016-03-30 | 中国科学院上海微系统与信息技术研究所 | Preparation method of NbN thin film, SQUID device and preparation method of SQUID device |
| CN105449094B (en) * | 2015-12-29 | 2019-04-05 | 中国科学院上海微系统与信息技术研究所 | The preparation method of niobium nitride film, SQUID device and preparation method thereof |
| CN108588653A (en) * | 2018-02-07 | 2018-09-28 | 中国科学院紫金山天文台 | The method for preparing titanium nitride superconducting thin film on a silicon substrate using magnetron sputtering method |
| CN114774868A (en) * | 2022-03-31 | 2022-07-22 | 南京大学 | Method for depositing niobium nitride on diamond based on ion polishing technology |
| CN116377407A (en) * | 2023-04-03 | 2023-07-04 | 之江实验室 | Low-stress NbN superconducting film and preparation method and application thereof |
| CN116377407B (en) * | 2023-04-03 | 2023-08-29 | 之江实验室 | Low-stress NbN superconducting film and preparation method and application thereof |
| CN117070892A (en) * | 2023-08-10 | 2023-11-17 | 之江实验室 | Two-step control N 2 Method for reducing internal stress of NbN film and improving superconducting transition temperature by partial pressure |
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