EP0856868A2 - Herstellungsverfahren einer Feldemissionselektronenquelle und nach diesem Verfahren hergestellter Feldemissionselektronenquelle - Google Patents

Herstellungsverfahren einer Feldemissionselektronenquelle und nach diesem Verfahren hergestellter Feldemissionselektronenquelle Download PDF

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Publication number
EP0856868A2
EP0856868A2 EP98201095A EP98201095A EP0856868A2 EP 0856868 A2 EP0856868 A2 EP 0856868A2 EP 98201095 A EP98201095 A EP 98201095A EP 98201095 A EP98201095 A EP 98201095A EP 0856868 A2 EP0856868 A2 EP 0856868A2
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EP
European Patent Office
Prior art keywords
microtips
microtip
source
grids
etching
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.)
Granted
Application number
EP98201095A
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English (en)
French (fr)
Other versions
EP0856868B1 (de
EP0856868A3 (de
Inventor
Robert Meyer
Pierre Vaudaine
Philippe Rambaud
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Commissariat a lEnergie Atomique et aux Energies Alternatives CEA
Original Assignee
Commissariat a lEnergie Atomique CEA
Priority date (The priority date 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 date listed.)
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Publication date
Priority claimed from FR9404948A external-priority patent/FR2719155B1/fr
Application filed by Commissariat a lEnergie Atomique CEA filed Critical Commissariat a lEnergie Atomique CEA
Publication of EP0856868A2 publication Critical patent/EP0856868A2/de
Publication of EP0856868A3 publication Critical patent/EP0856868A3/de
Application granted granted Critical
Publication of EP0856868B1 publication Critical patent/EP0856868B1/de
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J9/00—Apparatus or processes specially adapted for the manufacture, installation, removal, maintenance of electric discharge tubes, discharge lamps, or parts thereof; Recovery of material from discharge tubes or lamps
    • H01J9/02—Manufacture of electrodes or electrode systems
    • H01J9/022—Manufacture of electrodes or electrode systems of cold cathodes
    • H01J9/025—Manufacture of electrodes or electrode systems of cold cathodes of field emission cathodes
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J1/00—Details of electrodes, of magnetic control means, of screens, or of the mounting or spacing thereof, common to two or more basic types of discharge tubes or lamps
    • H01J1/02—Main electrodes
    • H01J1/30—Cold cathodes, e.g. field-emissive cathode
    • H01J1/304—Field-emissive cathodes
    • H01J1/3042—Field-emissive cathodes microengineered, e.g. Spindt-type

Definitions

  • the present invention relates in a way general to cathodic emissive systems using electronic emission by field effect such as by example those of the matrix flat screens used for display of images; it relates more precise, to a process making it possible to improve the characteristics of microtip cathodes and their uniformity over large areas.
  • microtip emissive system and its manufacturing process are described in detail by example in document FR-A-2 593 953 of 24/01/1986. We will begin by recalling the known technique for manufacturing such microtips in a structure of this kind, as it emerges from aforementioned document with reference to Figures 1, 2 and 3 attached.
  • Figure 1 shows an already developed structure, comprising on a substrate 6 surmounted by an insulator 7, a system of cathode conductors 8 and grids 10a superimposed in cross form with insulation intermediate 12 and a layer for example of nickel 23 deposited on the surface to serve as a mask during microtip production operations.
  • This layer 23 of nickel, the grids 10a and the insulator 12 are drilled with holes 16, at the bottom of which is to come and deposit the future microtips made of an electrically conductive metal with the cathode electrode 8.
  • microtips as well obtained have certain defects. These faults first come from the fact that the previous method makes it difficult to obtain microtips, the shape is reproducible from one point to another and / or from one cathode to another, especially on large surfaces during mass production. They also come from the fact that, on the other hand, microtips obtained are far from always having the perfect conical shape which we have represented under the reference 18 in FIGS. 2 and 3. Most often in indeed, they have shape inequalities and a majority has a much too large radius of curvature, this which gives them a domed profile as we can see in Figure 4. This domed profile notably decreases their emissivity in a considerable way, that is to say the current density emitted for a grid voltage determined microtip.
  • the realization of the cathode requires at least one photolithography step intervening after the realization of the points in particular for the definition of the conductive strips forming the grids. This step creates pollution risks important on the tips (organic residues, traces of cleaning,).
  • the emissivity of a point varies so exponential with the shape of the tip and its state of area.
  • the object of the present invention is precisely a process for producing electron sources using microtips which allows both to standardize the state of surface and to refine the geometry of the microtips.
  • This process thus makes it possible by greatly reducing the dispersions of characteristics from point to point the other and from one source to another to compensate for previous disadvantages and make it easier the production of microtip cathodes with uniform and reproducible characteristics, as well than a high emission level.
  • the invention proposes carry out, as a first step, a cleaning which makes it possible to standardize the surface condition and, secondly, a refining step which consists of an additional engraving to give microtips a profile as close as possible to the ideal desired, i.e. with a radius of curvature as small as possible (less than a few tens of nanometers).
  • this optimization consists of search, for microtips, of a profile as close as possible to a tapered cone tapered, in other words in search of an effect of tips increased to guarantee a large amplitude of the electric field.
  • the step is followed refining of a second cleaning step, consisting of wet chemical cleaning.
  • the first cleaning step comprises a first wet chemical cleaning sub-step and a second cleaning sub-step with a plasma, for example with O 2 plasma.
  • the refining step by surface etching can be achieved by one any of the known methods which are in particular controlled chemical or electrochemical attack, the attack by reactive ion etching and the attack by ion bombardment.
  • the surface attack microtips is performed over a thickness of a few tens to a few thousand Angstroms.
  • One of the advantages of the process which is the subject of the present invention is that it applies to treatment very large emissive surfaces, such as meets precisely in flat screens display.
  • the process thus makes it possible to correct very simply the approximate shape of the microtips obtained to date and, by removing the dispersal of peak emission characteristics to the other, to allow a level of emission very high and significantly increased electronics compared to those of the prior art, and therefore allow the reduction of the supply voltage required between the grids and cathode conductors for extract the electrons.
  • the principle of the invention consists in choose a method for producing microtips which gives them an approximate form (more easy to carry out on large surfaces and less expensive) then cleaning the microtips and finally improve and homogenize their radius of curvature to using, in particular, reactive ion etching or other methods of chemical etching or electrochemical.
  • the first part (base) is height such that its top is about the same level than the lower plane of the grid.
  • the ripening time must be checked: if it is too important, the top of the tip can quickly find below the lower plane of the grid, this which is very unfavorable to electronic transmission. If it is too small, the radius of curvature is not optimum and the effect sought by the refining is not achieved.
  • the ripening time must be sufficient to obtain the optimum radius of curvature of the tip, but if it is longer, the top of the tip always stays above of the lower plane of the grid since it rests on unattacked or slightly attacked material.
  • the first part is niobium (Nb)
  • the second part is molybdenum, or chromium, or silicon, or iron, or nickel.
  • the height H is such that the summit of the first part is substantially at level of the lower plane of the grids.
  • the invention thus applies to sources in which microdots are not deposited directly on the cathode conductors but by example on a resistive layer inserted between the microtips and cathode conductors.
  • This last operation which lasts about ten minutes is done for example with a power of 250 Watts, a plasma pressure of 100 millitorrs and a flow rate of 100 cm 3 / min.
  • the cleaning step is followed by a step of refining or etching the tips, for example for molybdenum tips by reactive ion etching in an SF 6 plasma (same equipment as that mentioned above).
  • This step eliminates a layer of molybdenum oxide which may have formed during cleaning under O 2 plasma. It also allows microtip etching to modify their shape and in particular to reduce their radius of curvature.
  • the conditions of action of the sulfur hexafluoride plasma are for example the following: the operation lasts approximately 20 seconds with a power of 400 W, a flow rate of 40 cm 3 / min under a plasma pressure of 30 millitorrs. At the end of this treatment, a high proportion of microtips have the same profile which approximates the ideal cone profile of FIG. 5 and a very uniform surface condition.
  • Figure 6a is a curve showing emissivity of microtips before treatment ripening (dotted curve) and after treatment ripening (solid line curve).
  • current density in microamps per millimeter square is plotted on the ordinate and the grid-microtip voltage in volts is plotted on the abscissa.
  • the increase in emissivity following treatment immediately appears to be considerable. We therefore effectively obtains microtips, for which the radius of curvature of the end is less than a few tens of nanometers.
  • Figure 6b shows emissivity (same units as in FIG. 6a) of the microtips after refining, but before (dotted curve) and after the second cleaning step (curve in solid line). We see that this second cleaning step still allows improve the emissivity of an important factor.
  • tip refining processes can be used as an alternative to the one described above, for example by chemical attack (or electrochemical) controlled or by ion bombardment.
  • the duration, during which the stage is carried out must be checked in the event that the microdots are made of a single sensitive metal refining, for example molybdenum.
  • the grid 10a is geometrically understood between or delimited by two planes, a lower plane (I) and an upper plane (S) (see figure 7a, on which, as in FIGS. 7b, 7c, 8a-c, the references 6, 8, 10a, 12 have the same meaning as in Figures 1 to 5).
  • the ripening time should be long enough to obtain the optimum radius of curvature, but despite everything not too long for the tip to remain above the lower plane I of the grid (FIG. 7c).
  • a method for obtaining microtips having this structure is derived from the process already described in introduction to making microtips made of a single material.
  • the whole then has the overall shape substantially conical of Figure 8a.
  • the height H of the base 20 must be sufficient for the vertex A of the cone obtained to be located above the lower plane of the grid 10a.
  • A will be located, after the deposit operations which have just been described, above the plan upper of the grid 10a; for this purpose, the height H will be substantially equal to the thickness of the insulation 12, that is to say in this embodiment, at the distance separating the cathode conductor 8 from the plane lower of the grid 10a.
  • a microtip cathode obtained by the method described in the present invention can be associated with a structure comprising at least one anode and a cathodoluminescent material to achieve a display device as described in US Patents 4,857,161 (FR-2,593,953), US 4,940,916, US.5 225 820 (FR-2 633 763) or US.5 194 780 (FR-A-2 663 462).

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  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Cold Cathode And The Manufacture (AREA)
  • Inks, Pencil-Leads, Or Crayons (AREA)
  • Chemical Or Physical Treatment Of Fibers (AREA)
EP98201095A 1994-04-25 1995-04-24 Feldemissionselektronenquelle und Bildschirm mit solcher Feldemissionselektronenquelle Expired - Lifetime EP0856868B1 (de)

Applications Claiming Priority (5)

Application Number Priority Date Filing Date Title
FR9404948 1994-04-25
FR9404948A FR2719155B1 (fr) 1994-04-25 1994-04-25 Procédé de réalisation de sources d'électrons à micropointes et source d'électrons à micropointes obtenue par ce procédé.
FR9413972 1994-11-22
FR9413972A FR2719156B1 (fr) 1994-04-25 1994-11-22 Source d'électrons à micropointes, les micropointes comportant deux parties.
EP95400910A EP0689222B1 (de) 1994-04-25 1995-04-24 Herstellungsverfahren einer Mikrospitzelektronenquelle

Related Parent Applications (1)

Application Number Title Priority Date Filing Date
EP95400910A Division EP0689222B1 (de) 1994-04-25 1995-04-24 Herstellungsverfahren einer Mikrospitzelektronenquelle

Publications (3)

Publication Number Publication Date
EP0856868A2 true EP0856868A2 (de) 1998-08-05
EP0856868A3 EP0856868A3 (de) 1998-09-30
EP0856868B1 EP0856868B1 (de) 2003-07-02

Family

ID=26231113

Family Applications (2)

Application Number Title Priority Date Filing Date
EP95400910A Expired - Lifetime EP0689222B1 (de) 1994-04-25 1995-04-24 Herstellungsverfahren einer Mikrospitzelektronenquelle
EP98201095A Expired - Lifetime EP0856868B1 (de) 1994-04-25 1995-04-24 Feldemissionselektronenquelle und Bildschirm mit solcher Feldemissionselektronenquelle

Family Applications Before (1)

Application Number Title Priority Date Filing Date
EP95400910A Expired - Lifetime EP0689222B1 (de) 1994-04-25 1995-04-24 Herstellungsverfahren einer Mikrospitzelektronenquelle

Country Status (5)

Country Link
US (1) US5635790A (de)
EP (2) EP0689222B1 (de)
CA (1) CA2146528A1 (de)
DE (2) DE69531220T2 (de)
FR (1) FR2719156B1 (de)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1174899A2 (de) * 2000-07-17 2002-01-23 Hewlett-Packard Company Elektronenquellenvorrichtung

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5702281A (en) * 1995-04-20 1997-12-30 Industrial Technology Research Institute Fabrication of two-part emitter for gated field emission device
US6356014B2 (en) * 1997-03-27 2002-03-12 Candescent Technologies Corporation Electron emitters coated with carbon containing layer
US6004180A (en) * 1997-09-30 1999-12-21 Candescent Technologies Corporation Cleaning of electron-emissive elements
US6873097B2 (en) * 2001-06-28 2005-03-29 Candescent Technologies Corporation Cleaning of cathode-ray tube display
CN1300818C (zh) * 2003-08-06 2007-02-14 北京大学 一种场发射针尖及其制备方法与应用

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0434330A2 (de) * 1989-12-18 1991-06-26 Seiko Epson Corporation Feldemissionsvorrichtung und Verfahren zur Herstellung derselben
EP0443920A1 (de) * 1990-02-23 1991-08-28 Thomson-Csf Verfahren zur gesteuerten Züchtung von nadelförmigen Kristallen und ihre Verwendung zur Herstellung spitzenförmiger Mikrokathoden
EP0535953A2 (de) * 1991-10-02 1993-04-07 Sharp Kabushiki Kaisha Mit Feldemission arbeitende elektronische Vorrichtung
EP0570211A1 (de) * 1992-05-15 1993-11-18 Gec-Marconi Limited Kathodenstrukturen

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2593953B1 (fr) * 1986-01-24 1988-04-29 Commissariat Energie Atomique Procede de fabrication d'un dispositif de visualisation par cathodoluminescence excitee par emission de champ
FR2623013A1 (fr) * 1987-11-06 1989-05-12 Commissariat Energie Atomique Source d'electrons a cathodes emissives a micropointes et dispositif de visualisation par cathodoluminescence excitee par emission de champ,utilisant cette source
US5225820A (en) * 1988-06-29 1993-07-06 Commissariat A L'energie Atomique Microtip trichromatic fluorescent screen
FR2663462B1 (fr) * 1990-06-13 1992-09-11 Commissariat Energie Atomique Source d'electrons a cathodes emissives a micropointes.
US5203731A (en) * 1990-07-18 1993-04-20 International Business Machines Corporation Process and structure of an integrated vacuum microelectronic device

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0434330A2 (de) * 1989-12-18 1991-06-26 Seiko Epson Corporation Feldemissionsvorrichtung und Verfahren zur Herstellung derselben
EP0443920A1 (de) * 1990-02-23 1991-08-28 Thomson-Csf Verfahren zur gesteuerten Züchtung von nadelförmigen Kristallen und ihre Verwendung zur Herstellung spitzenförmiger Mikrokathoden
EP0535953A2 (de) * 1991-10-02 1993-04-07 Sharp Kabushiki Kaisha Mit Feldemission arbeitende elektronische Vorrichtung
EP0570211A1 (de) * 1992-05-15 1993-11-18 Gec-Marconi Limited Kathodenstrukturen

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1174899A2 (de) * 2000-07-17 2002-01-23 Hewlett-Packard Company Elektronenquellenvorrichtung
EP1174899A3 (de) * 2000-07-17 2002-09-18 Hewlett-Packard Company Elektronenquellenvorrichtung

Also Published As

Publication number Publication date
EP0689222A2 (de) 1995-12-27
EP0689222A3 (de) 1996-02-07
EP0856868B1 (de) 2003-07-02
DE69514576T2 (de) 2000-08-10
EP0856868A3 (de) 1998-09-30
EP0689222B1 (de) 2000-01-19
DE69531220T2 (de) 2004-05-27
US5635790A (en) 1997-06-03
DE69514576D1 (de) 2000-02-24
FR2719156B1 (fr) 1996-05-24
DE69531220D1 (de) 2003-08-07
CA2146528A1 (en) 1995-10-26
FR2719156A1 (fr) 1995-10-27

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