EP0689722A1 - Geraet und verfahren zum datieren von feststoffmaterial - Google Patents
Geraet und verfahren zum datieren von feststoffmaterialInfo
- Publication number
- EP0689722A1 EP0689722A1 EP93905317A EP93905317A EP0689722A1 EP 0689722 A1 EP0689722 A1 EP 0689722A1 EP 93905317 A EP93905317 A EP 93905317A EP 93905317 A EP93905317 A EP 93905317A EP 0689722 A1 EP0689722 A1 EP 0689722A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- accordance
- solid material
- doping
- electrode
- selected region
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Withdrawn
Links
- 238000000034 method Methods 0.000 title claims abstract description 57
- 239000011343 solid material Substances 0.000 title claims description 35
- 239000000463 material Substances 0.000 claims abstract description 33
- 239000002019 doping agent Substances 0.000 claims abstract description 16
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims abstract description 15
- 229910052760 oxygen Inorganic materials 0.000 claims abstract description 14
- 239000001301 oxygen Substances 0.000 claims abstract description 14
- 239000002887 superconductor Substances 0.000 claims abstract description 7
- 239000003792 electrolyte Substances 0.000 claims description 16
- 230000005684 electric field Effects 0.000 claims description 9
- 239000003822 epoxy resin Substances 0.000 claims description 3
- 239000012530 fluid Substances 0.000 claims description 3
- 229920000647 polyepoxide Polymers 0.000 claims description 3
- 239000004065 semiconductor Substances 0.000 claims description 2
- 239000012141 concentrate Substances 0.000 claims 1
- 239000011148 porous material Substances 0.000 claims 1
- 239000002243 precursor Substances 0.000 claims 1
- 239000007787 solid Substances 0.000 abstract description 5
- 230000005641 tunneling Effects 0.000 abstract description 5
- 239000010408 film Substances 0.000 description 45
- 239000000758 substrate Substances 0.000 description 11
- 239000010409 thin film Substances 0.000 description 8
- 238000000151 deposition Methods 0.000 description 7
- 230000008021 deposition Effects 0.000 description 7
- 150000002500 ions Chemical class 0.000 description 6
- 238000005259 measurement Methods 0.000 description 6
- 239000010949 copper Substances 0.000 description 5
- 229920000642 polymer Polymers 0.000 description 5
- 230000004888 barrier function Effects 0.000 description 4
- 238000001075 voltammogram Methods 0.000 description 4
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 description 3
- 230000008901 benefit Effects 0.000 description 3
- 238000009792 diffusion process Methods 0.000 description 3
- 238000004070 electrodeposition Methods 0.000 description 3
- 238000005530 etching Methods 0.000 description 3
- 238000000059 patterning Methods 0.000 description 3
- 238000000206 photolithography Methods 0.000 description 3
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Chemical compound [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 description 3
- 238000006722 reduction reaction Methods 0.000 description 3
- 229910002282 La2CuO4 Inorganic materials 0.000 description 2
- 238000002441 X-ray diffraction Methods 0.000 description 2
- 238000006243 chemical reaction Methods 0.000 description 2
- 238000000576 coating method Methods 0.000 description 2
- 150000001875 compounds Chemical class 0.000 description 2
- 239000013078 crystal Substances 0.000 description 2
- 239000008151 electrolyte solution Substances 0.000 description 2
- 230000004907 flux Effects 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 238000001451 molecular beam epitaxy Methods 0.000 description 2
- 229920002120 photoresistant polymer Polymers 0.000 description 2
- 230000008569 process Effects 0.000 description 2
- 230000002441 reversible effect Effects 0.000 description 2
- 238000004574 scanning tunneling microscopy Methods 0.000 description 2
- 239000000243 solution Substances 0.000 description 2
- 238000004544 sputter deposition Methods 0.000 description 2
- 241000238366 Cephalopoda Species 0.000 description 1
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 1
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 1
- 239000004809 Teflon Substances 0.000 description 1
- 229920006362 Teflon® Polymers 0.000 description 1
- 230000001476 alcoholic effect Effects 0.000 description 1
- 238000000089 atomic force micrograph Methods 0.000 description 1
- 238000004630 atomic force microscopy Methods 0.000 description 1
- 229940075397 calomel Drugs 0.000 description 1
- 230000008859 change Effects 0.000 description 1
- 238000005229 chemical vapour deposition Methods 0.000 description 1
- 239000011248 coating agent Substances 0.000 description 1
- 239000002322 conducting polymer Substances 0.000 description 1
- 229920001940 conductive polymer Polymers 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 229910052802 copper Inorganic materials 0.000 description 1
- 229910000366 copper(II) sulfate Inorganic materials 0.000 description 1
- 125000004122 cyclic group Chemical group 0.000 description 1
- 230000002542 deteriorative effect Effects 0.000 description 1
- 230000001627 detrimental effect Effects 0.000 description 1
- 239000003989 dielectric material Substances 0.000 description 1
- ZOMNIUBKTOKEHS-UHFFFAOYSA-L dimercury dichloride Chemical compound Cl[Hg][Hg]Cl ZOMNIUBKTOKEHS-UHFFFAOYSA-L 0.000 description 1
- 238000009826 distribution Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000003487 electrochemical reaction Methods 0.000 description 1
- 238000000609 electron-beam lithography Methods 0.000 description 1
- 230000008020 evaporation Effects 0.000 description 1
- 238000001704 evaporation Methods 0.000 description 1
- LNEPOXFFQSENCJ-UHFFFAOYSA-N haloperidol Chemical compound C1CC(O)(C=2C=CC(Cl)=CC=2)CCN1CCCC(=O)C1=CC=C(F)C=C1 LNEPOXFFQSENCJ-UHFFFAOYSA-N 0.000 description 1
- 229910052739 hydrogen Inorganic materials 0.000 description 1
- 239000001257 hydrogen Substances 0.000 description 1
- 239000007943 implant Substances 0.000 description 1
- 239000012535 impurity Substances 0.000 description 1
- 238000010348 incorporation Methods 0.000 description 1
- 239000012212 insulator Substances 0.000 description 1
- 229910052747 lanthanoid Inorganic materials 0.000 description 1
- 150000002602 lanthanoids Chemical class 0.000 description 1
- 229910052746 lanthanum Inorganic materials 0.000 description 1
- FZLIPJUXYLNCLC-UHFFFAOYSA-N lanthanum atom Chemical compound [La] FZLIPJUXYLNCLC-UHFFFAOYSA-N 0.000 description 1
- 239000011244 liquid electrolyte Substances 0.000 description 1
- 239000007769 metal material Substances 0.000 description 1
- 229910044991 metal oxide Inorganic materials 0.000 description 1
- 150000004706 metal oxides Chemical class 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
- 230000001590 oxidative effect Effects 0.000 description 1
- 230000002093 peripheral effect Effects 0.000 description 1
- -1 perovskites (SrFe03 Chemical class 0.000 description 1
- 229920006254 polymer film Polymers 0.000 description 1
- 239000002244 precipitate Substances 0.000 description 1
- 230000009467 reduction Effects 0.000 description 1
- 229920002379 silicone rubber Polymers 0.000 description 1
- 239000004945 silicone rubber Substances 0.000 description 1
- 239000002904 solvent Substances 0.000 description 1
- 238000009987 spinning Methods 0.000 description 1
- 239000001993 wax Substances 0.000 description 1
- 229910052727 yttrium Inorganic materials 0.000 description 1
- VWQVUPCCIRVNHF-UHFFFAOYSA-N yttrium atom Chemical compound [Y] VWQVUPCCIRVNHF-UHFFFAOYSA-N 0.000 description 1
Classifications
-
- H—ELECTRICITY
- H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
- H10N—ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
- H10N60/00—Superconducting devices
- H10N60/01—Manufacture or treatment
- H10N60/0268—Manufacture or treatment of devices comprising copper oxide
- H10N60/0661—Processes performed after copper oxide formation, e.g. patterning
-
- H—ELECTRICITY
- H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
- H10N—ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
- H10N60/00—Superconducting devices
- H10N60/01—Manufacture or treatment
- H10N60/0912—Manufacture or treatment of Josephson-effect devices
- H10N60/0941—Manufacture or treatment of Josephson-effect devices comprising high-Tc ceramic materials
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01Q—SCANNING-PROBE TECHNIQUES OR APPARATUS; APPLICATIONS OF SCANNING-PROBE TECHNIQUES, e.g. SCANNING PROBE MICROSCOPY [SPM]
- G01Q80/00—Applications, other than SPM, of scanning-probe techniques
Definitions
- This invention relates to a method and apparatus for implanting dopants into a solid material, preferably a thin film of solid material. Specifically, it pertains to a, preferably reversible, method of preparing a pattern of superconducting material in an otherwise non-superconducting material or vice versa. More specifically, the invention concerns a method of implanting or extracting oxygen from solid material. It further relates to producing patterns having a resolution higher than one ⁇ m.
- Background of the invention is the doping of solid material, particular of thin films of solid material.
- Solid material as defined within the scope of this invention comprises non-organic crystal and amorphous matter.
- the process of doping is well known in the production of semiconducting devices.
- Several techniques to produce a dopant distribution of high resolution, i.e. having lateral dimensions of less than 1 /tm, are known.
- photolithographical techniques are used; photolithography is based on spinning a photosensitve polymer on top of the solid material. This polymer layer is exposed to UV-light through a mask which shows the desired pattern.
- either the exposed area or the area of the layer which has been left unexposed can be easily removed by a solvent, leaving the selected region of the surface of the host material uncovered either for a subsequent diffusion of the dopant into the solid, for selectively etching doped material, or for extracting atoms from the solid material.
- photolithography to extract oxygen from a superconducting material, is described, for example, in the European patent application 0 484 248.
- electrochemical deposition Another technical field related to the invention is known as electrochemical deposition. Though a variety of different techniques are known, in the basic apparatus, an electrochemical cell with two electrodes is applied.
- the material serving as substrate is connected to one of the electrodes while the electrolyte or the counterelectrode contains the material as ions to be deposited onto said substrate.
- a (faradaic) current through the electrolyte, a discharge and a subsequent deposition of the ions can be achieved.
- the electrochemical deposition method is usually not suitable for the purpose of doping, i.e. when the dopants have to be implanted within the solid material.
- the European patent application 0 434 480 or Physica C 173 (1991 ) pages 139-144, it is known to implant oxygen into a solid material.
- the current invention is partly based on this method for electrochemically oxidizing a superconducting material.
- the oxidation process described in these references is not locally confinable and, hence, can not be used for generating a pattern.
- High resolution patterning in an electrochemical cell is known, for example, from US patent 4 968 390. It proposes an electrochemical deposition method in which a modified version of the scanning tunneling microscope (STM) is used as one electrode.
- the substrate serving as the other electrode is covered by an ionic conducting polymer film as electrolyte containing the ions to be deposited.
- the ions move within the polymer film under the influence of the electric field towards the electrodes. However, they do not diffuse into the substrate, but form patterns at the interface between the film and the neighbouring material. Thus, diffusion takes place only in the electrolyte, itself.
- the resolution of lines deposited at the polymer/substrate interface show a significantly lower resolution, as the distance between the substrate and the tip of the STM is necessarily larger than the film thickness.
- an object of the invention to provide a method and an apparatus for implanting dopants into solid materials or films thereof. It is another object of the invention to provide regions in a solid material having a lesser or higher oxygen content than the surrounding material. It is yet another object of the invention to provide a method and an apparatus for producing a pattern consisting of superconductive material within a non-superconductive host material or vice versa, wherein the patterning is preferably reversible. Another object of the invention is to provide a method and apparatus for producing a pattern with submicron resolution.
- the new doping method uses an electrochemical cell comprising an fluid electrolyte containing the dopant and at least two electrodes to which a voltage is applied to create an electrical field wherein the electrical field is essentially concentrated at a selected region effectively restricting the doping to this region of the solid material.
- Any conventional electric cell can be utilized for employing the new method.
- the cell may contain two compartments separated for example by a frit.
- the voltage between the electrodes can be controlled more accurately by using a third (reference) electrode, e.g. a calomel electrode or a hydrogen electrode. Between both electrodes, a voltage is applied the amount of which strongly depends on the used materials and the distance between both electrodes.
- a voltage ranging from 100 mV to 5V, preferably from 200mV to 1V has been found to be suitable for a wide range of applications.
- a person skilled in the art usually relies on a measurement of a (cyclic) voltammogram, i.e. the measurement of the current as a function of the applied voltage. Changes in the slope of this current function indicate the onset of an electrochemical reaction.
- a person skilled in the art is able to establish an optimum value for the voltage by analyzing the voltammogram.
- a constant voltage or a sequence of short pulses can be applied.
- the confinement of the doping to the selected regions is achieved by adapting the geometry of the counterelectrode and the distance between both electrodes in accordance with the desired pattern. Depending on the required resolution, the distance between both electrodes may vary between 0.1 nm and 100 m.
- the counterelectrode consists of a single, ultrafine tip, which is scanned over the selected regions, or the utmost part of the counterelectrode is patterned in conformity with the selected regions or at least a part of them.
- Such a patterned electrode is manufactured by using conventional photolithograpy or, if submicron resolution is desired, by electron beam lithography.
- a combination of the above arrangements is the use of an electrode to which several tips have been attached, and which, hence, allows doping in parallel.
- the single tip With a single tip a very high resolution is achievable as the single tip can be sharped within atomic dimensions by using known techniques, such as etching, sputtering or field evaporation.
- the movement of the tip in vertical (z-) direction is controlled by means of a known scanning tunneling microscope feedback control keeping the current flow through the tip constant.
- the tunnel current is blotted by the larger faradaic current.
- the faradaic current By keeping the faradaic current constant, the amount of dopant at the surface of the host material is simultaneously controlled, resulting in a pattern with uniform line width. Beside the constant-current mode, it is further possible to keep the distance between the two electrodes constant.
- a desired pattern is written by either moving the tip over the surface of the other electrode or by moving this electrode in lateral (x-,y-) directions.
- the fine movement of the electrodes can best be performed by using a piezoelectric transducer submitted to an appropriate voltage.
- the scanning movement can be reduced to a relatively coarse positioning.
- the movement in z-direction still requires a fine positioning and is, thus, done by piezoelectric transducers attached to the tip or patterned electrode.
- the electrode - counterelectrode distance is kept below 1 m.
- the electrodes are preferably spaced in tunneling distance (0.1 nm to 10nm), i.e. the distance in which a tunnel current can be measured. A careful choice of this distance allows to vary the resolution of the pattern considerably, as the lateral spread of the faradaic current varies with said distance.
- Changes of a linewidth in the range of an order of magnitude, for example from 1 nm to 100 nm or even larger, can be achieved.
- the new method not only extremely small lines but also wider lines can be written by enlarging the distance between the electrodes. With the distance, the area at which the doping takes place increases roughly linear.
- the resolution is further improved by coating the counterelectrode, with the exception of its ultimate tip, i.e. its utmost part by a dielectric material.
- the ionic current is, thus, restricted to the uncovered part of the counterelectrode.
- the counterelectrode can be insulated or covered to a large extend by using apiezon wax, teflon, epoxy resins or similar materials. Only the utmost tip or edge of the electrode is freed or kept free from this insulating layer.
- the coatings produced by these known methods have typically a thickness of more than 1 m and leave several ⁇ m 2 of a tip uncovered.
- the electrochemical doping is confined to selected regions by covering the solid material with a photoresist which is insoluble in the electrolyte, and create the selected regions by using conventional photolithography. The solid material with the remaining parts of the photoresist is then exposed to the electrochemical doping. This method is insensitive to the shape of the counterelectrode and the interelectrode distance.
- the methods described above are applicable to semiconducting and metallic materials. Preferably, they are applied to semiconducting or superconducting metal oxides, such as perovskites (SrFe0 3 , La 2 Ni0 4 ). Examples of suitable superconducting materials are listed in the European patent application 0 426 570, page 3, lines 36-55.
- Suitable superconductors belong to the ' infinite layers" category, such as Ca,_ x Sr x CuO y , with Ln standing for an element selected from the lanthanides, including yttrium and lanthanum, Ba,_ x Sr x CuO y , and compounds of the above-mentioned category, including dopants selected from the group comprising C, N, F, and CI, or electron-doped superconductors.
- the invention is preferably applicable to films of the above mentioned materials.
- Films of solids are characterized by their compounds, their thickness, and by crystallographic parameters.
- the orientation of a crystal axis of the film material is used with respect to the substrate onto which it is deposited.
- an "a-axis orientated film” is a thin film the a-axis of which is oriented perpendicular to the surface of the substrate.
- the new method is found to be applicable to thin films without regard to their crystallographic orientation, i.e a-, b-, or c-axis films.
- a thin film is defined by having a thickness in the range of 1 nm to 5/rn ⁇ , preferably in the range of 10nm to 0.9 m. It is produced by using conventional techniques, e.g. sputtering, molecular beam epitaxy, or metaiorganic chemical vapor deposition, and the like.
- the new method can not only be applied for simple isolating, semiconducting, metallic, or superconducting thin films, but also to a variety of heterostructures wherein the film is either on top of a structure such as a metallic layer, a bilayer system (metallic layer / thin insulator) and any other combination of this kind, and/or is covered by such a structure.
- the new method can be applied stepwise, in the sense that first one layer of a film is doped, and after deposition of the next film layer on top of the existing structure, the method is applied again. Stacks of patterned layers on top of each other can thus be produced.
- a metallic layer beneath the film can by used, for example, as a contact area for applying the voltage to the film.
- a film of potentially superconducting material is doped with oxygen.
- liquid electrolytes containing KOH, NaOH, or H 2 SO., in an aqueous or alcoholic solution can be used.
- the counterelectrode is brought close to the surface of the film using the standard STM techniques described above. Then the voltage between counterelectrode and film is increased up to the voltage region required for the doping reaction. Locally - as defined by the uncovered tip region - oxygen is introduced into the film.
- oxidized regions can be defined.
- the critical temperature of the superconductor can be varied locally and continuously in the range from 0°K up to the optimum value of said superconducting material.
- the improved control over the oxygen content of the film forms a major advantage of the new method over the existing techniques.
- focussed beam techniques also used for patterning superconductors damage, to a certain extent, the surface of the film, deteriorating its superconducting properties. The edges and boundaries formed by applying the new method are found to have less detrimental influence on the superconductivity.
- the voltage between electrode and counterelectrode is shifted into a voltage region in which a reduction reaction takes place.
- a person skilled in the art can identify this region in the voltammogram.
- This method not only allows to transform selected regions of a superconducting material into non-superconducting material, but also enables a reversal of the writing step by the use of the same apparatus. Thus, it is suitable for producing barriers of non-superconducting material in otherwise superconducting material. If these barriers are produced with a thickness of less than 10 nm, they can be used for the manufacturing of Josephson contacts, SQUIDs, or superconducting FETs.
- Another preferred dopant is Cu, which is, for example, applicable as a solution of CuS0 4 .
- Cu is, for example, applicable as a solution of CuS0 4 .
- the use of copper as dopant offers similar advantages as the use of oxygen.
- the preferred embodiments of the invention are also specified in the claims. LIST OF THE DRAWINGS
- FIG. 1 shows a schematic drawing of an apparatus as used for the new method.
- FIGs. 2-4 show various superconducting films patterned in accordance with embodiments of the invention.
- FIG. 5 shows a two-layer superconducting film patterned in accordance with another embodiment of the new method.
- FIG.1 shows the basic components of an apparatus utilized for the new method.
- the apparatus is largely designed after the scanning tunneling microscope (STM).
- the means (not shown) for moving the tip 1 in x,y,z-directions relatively to the solid film 2 comprises piezoelectric transducers controlled by a voltage source, a feedback position controller, and a comparator to minimize the difference between the current flowing through the tip 1 and a constant reference current.
- the apparatus comprises a source to apply a voltage V 0 between the film 2 and the tip 1 .
- the tip 1 itself consists of a platinum wire 3 trimmed by electrochemical etching and an insulating cover 4 of epoxy resin. Only the utmost part of the wire 3 is left uncovered.
- the thin film 2 of La 2 Cu0 4 is grown in a layer-by-layer deposition mode using molecular beam epitaxy on a substrate 6.
- the deposition conditions include a substrate temperature of 700°C, an atomic oxygen flux of approximately 4 x 10' 4 and an oxygen background pressure of 1.5 x 10- 7 Torr. The growth is observed to ensure that the surface of the film is not contaminated with impurity phases. After a thickness t of 260 nm is reached, deposition is stopped and the sample is cooled to room temperature with the atomic oxygen flux shut off.
- the prepared film 2 has a room temperature resistance - measured with a two point contact technique - of 2 M ⁇ .
- X-ray diffraction indicate that the film is single phase c-axis oriented with a value of the c-axis of 1.30984 nm.
- Atomic force microscopy pictures taken from the surface reveal a relatively smooth surface with a roughness of + /- 5 nm. No large precipitates on the surface are detectable.
- the film 2 and the tip 1 are immersed in an electrolyte solution 5 of 1 N KOH. Electrical contacts to the film are made using a platinum wire and silverpaint. Afterwards, the contact area as well as the platinum wire are insulated from the electrolyte 5 using silicone rubber material.
- the tip 1 then is brought into a distance d of approximately 0.5 m to the film 2.
- a voltage V 0 of 550 mV between film and tip is applied.
- the voltage is periodically reduced from its peak value V 0 of 550 mV to 200 mV to allow a restoration of the original concentration of the electrolyte 5 in the spacing between tip and film and a measurement of the potential between both.
- the potential between both electrodes at an external voltage of zero allows to check the doping.
- the tip 1 is then moved relatively to the film 2 in accordance with a predetermined pattern.
- FIG.2 a line of superconducting La 2 CuO 4+(i 21 in otherwise non superconducting La 2 CuO 4 22 is shown. Taking the interruption of the movement during the time in which the voltage V 0 is reduced into account, the line 21 is produced with a scan speed of 20 nm/s. Its width is approximately 0.3//m.
- a new STM surface scan (at a lower voltage) is performed to check the surface conductivity.
- a larger sample is prepared by using a broader electrode and a larger distance d (2mm) between electrode and film.
- X-ray diffraction on said larger sample reveals that the c-axis lattice parameter has increased to 1.31464 nm in agreement with the incorporation of additional oxygen.
- the difference in lattice parameter between the oxidized and not oxidized sample is of the order of 0.005 nm.
- Atomic force microscope images show locally that the surface morphology did not change drastically. The features observed previously are slightly smeared out. Resistivity measurements indicate a superconducting onset of 30°K and a zero resistance state at 26°K. Finally kinetic inductance measurements prove that superconductivity in this system in not a surface but a bulk effect.
- the scanning speed is varied from 0 to 20 nm/s.
- FIG.3 shows a patterned superconducting region 31 produced by this method.
- a superconducting line 41 is initially generated in the film material 42 in accordance with the first example.
- V 0 is shifted to a value (250 mV), in which a reduction of the superconducting line 41 takes place.
- the accurate voltage for the reduction reaction is taken from a voltammogram.
- a non-superconductive barrier 43 is then produced by scanning the tip perpendicular to line 41. Again a sample of larger scale is prepared to prove that the barrier 43 penetrates the line 41 and the film 42 through its entire thickness.
- a 500 nm thick film 52 of La 2 Cu0 is grown on a film 54 of YBa 2 Cu 3 O 7 _ ⁇ with an equal thickness. Again 550 mV are applied between the films 52, 54 and the counterelectrode.
- the electrolyte is 1 N KOH.
- the film 54 of YBa 2 Cu 3 O 7 _ t 5 tends to be unstable.
- the film 52 of La 2 CuO thus serves as protecting layer.
- a scan speed of 100 nm/s is used. Under these conditions, in both layers 52, 54, a zone 51 , 53 of superconducting La 2 Cu0 4+ ,. and YBa 2 Cu 3 0 7 is produced, respectively.
Landscapes
- Engineering & Computer Science (AREA)
- Manufacturing & Machinery (AREA)
- Chemical & Material Sciences (AREA)
- Ceramic Engineering (AREA)
- Superconductor Devices And Manufacturing Methods Thereof (AREA)
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
PCT/EP1993/000522 WO1994020991A1 (en) | 1993-03-08 | 1993-03-08 | Method and apparatus for doping a solid material |
Publications (1)
Publication Number | Publication Date |
---|---|
EP0689722A1 true EP0689722A1 (de) | 1996-01-03 |
Family
ID=8165710
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP93905317A Withdrawn EP0689722A1 (de) | 1993-03-08 | 1993-03-08 | Geraet und verfahren zum datieren von feststoffmaterial |
Country Status (3)
Country | Link |
---|---|
EP (1) | EP0689722A1 (de) |
JP (1) | JP2812454B2 (de) |
WO (1) | WO1994020991A1 (de) |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP1608844A2 (de) * | 2003-03-07 | 2005-12-28 | Halliburton Energy Services, Inc. | Vorrichtung und verfahren zum testen und zur entnahme einer formation |
US7733086B2 (en) | 2003-05-02 | 2010-06-08 | Halliburton Energy Services, Inc. | Systems and methods for deep-looking NMR logging |
US7755354B2 (en) | 2003-10-03 | 2010-07-13 | Halliburton Energy Services, Inc. | System and methods for T1-based logging |
Families Citing this family (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US6251755B1 (en) | 1999-04-22 | 2001-06-26 | International Business Machines Corporation | High resolution dopant/impurity incorporation in semiconductors via a scanned atomic force probe |
DE10153053C2 (de) * | 2001-10-21 | 2003-10-09 | Hahn Meitner Inst Berlin Gmbh | Verfahren zur Erzeugung von p-n-Übergängen in einem Halbleiter |
JP2005340453A (ja) * | 2004-05-26 | 2005-12-08 | Nippon Telegr & Teleph Corp <Ntt> | 酸化物高温超伝導体高周波素子の作製方法 |
JP2006233276A (ja) * | 2005-02-25 | 2006-09-07 | Tokyo Institute Of Technology | 固体膜へのドーピング方法およびドーピング・パターン形成方法 |
Family Cites Families (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4392928A (en) * | 1982-01-26 | 1983-07-12 | The United States Of America As Represented By The United States Department Of Energy | Method of doping a semiconductor |
US4616200A (en) * | 1984-09-12 | 1986-10-07 | Square D Company | Circuit breaker |
DE3503264A1 (de) * | 1985-01-31 | 1986-08-07 | Max-Planck-Gesellschaft zur Förderung der Wissenschaften e.V., 3400 Göttingen | Verfahren zur aenderung der lokalen, atomaren zusammensetzung von festkoerpern, insbesondere halbleitern |
GB2249786A (en) * | 1990-11-01 | 1992-05-20 | Atomic Energy Authority Uk | Superconducting oxide materials |
-
1993
- 1993-03-08 WO PCT/EP1993/000522 patent/WO1994020991A1/en not_active Application Discontinuation
- 1993-03-08 JP JP6519495A patent/JP2812454B2/ja not_active Expired - Lifetime
- 1993-03-08 EP EP93905317A patent/EP0689722A1/de not_active Withdrawn
Non-Patent Citations (1)
Title |
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See references of WO9420991A1 * |
Cited By (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP1608844A2 (de) * | 2003-03-07 | 2005-12-28 | Halliburton Energy Services, Inc. | Vorrichtung und verfahren zum testen und zur entnahme einer formation |
EP1608844A4 (de) * | 2003-03-07 | 2006-11-22 | Halliburton Energy Serv Inc | Vorrichtung und verfahren zum testen und zur entnahme einer formation |
US7650937B2 (en) | 2003-03-07 | 2010-01-26 | Halliburton Energy Services, Inc. | Formation testing and sampling apparatus and methods |
US8235106B2 (en) | 2003-03-07 | 2012-08-07 | Halliburton Energy Services, Inc. | Formation testing and sampling apparatus and methods |
US8522870B2 (en) | 2003-03-07 | 2013-09-03 | Halliburton Energy Services, Inc. | Formation testing and sampling apparatus and methods |
US7733086B2 (en) | 2003-05-02 | 2010-06-08 | Halliburton Energy Services, Inc. | Systems and methods for deep-looking NMR logging |
US7755354B2 (en) | 2003-10-03 | 2010-07-13 | Halliburton Energy Services, Inc. | System and methods for T1-based logging |
Also Published As
Publication number | Publication date |
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JP2812454B2 (ja) | 1998-10-22 |
JPH08503339A (ja) | 1996-04-09 |
WO1994020991A1 (en) | 1994-09-15 |
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