CN101055828A - Image display device - Google Patents
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- CN101055828A CN101055828A CN 200610091865 CN200610091865A CN101055828A CN 101055828 A CN101055828 A CN 101055828A CN 200610091865 CN200610091865 CN 200610091865 CN 200610091865 A CN200610091865 A CN 200610091865A CN 101055828 A CN101055828 A CN 101055828A
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Abstract
The invention provides an image display device which comprises an electron source array and a fluorescent surface which can light because of being excited by the bombardment of the electron emitted by the electron source array. The electron source is provided with a lower part electrode, an upper part electrode and an electron acceleration layer comprising an insulator and a semiconductor between the lower part electrode and the upper part electrode. Electron is emitted from the upper part electrode and the upper part electrode applies platinum group metals (the eighth group) or noble metal of Ib group or the laminated film or alloy film thereof from the interface of the electron acceleration layer to the surface containing alkali metal or alkali oxide, thus promoting diode current with low threshold voltage, and even low voltage can guarantee the diode current needed by electron emission, and the image display device realizes long service life and low power consumption.
Description
Technical field
The present invention relates to a kind of image display device, be particularly useful for using electron source array Autoluminescence, also be known as the image display device of flat-panel monitor (flat panel display).
Background technology
Developed at present utilize trace, can be integrated the image display device (field-emitter display, Field Emission Display:FED) of cold cathode type electron source.The electron source of this image display device can be categorized into field emission formula electron source and thermoelectric minor electron source.Spindt formula electron source, surface conduction type electron source, carbon nano tube type electron source etc. belong to the former; The latter then comprises the MIM of metal-insulator-metal type (Metal-Insulator-Metal) formula stacked, stacked thin-film electro components such as the MIS of metal-insulator semiconductor (Metal-Insulator-Semiconductor) formula, metal-insulator semiconductor-metal type etc.
About the MIM formula, for example in patent documentation 1, introduced; Introduced MOS formula (non-patent literature 1) about the metal-insulator semiconductor formula; Introduced HEED formula (being recorded in non-patent literature 2 etc.), EL formula (being recorded in non-patent literature 3 etc.), porous silicon formula (being recorded in non-patent literature 4 etc.) etc. about metal-insulator semiconductor-metal type.
[patent documentation 1] Japanese kokai publication hei 7-65710 communique
[patent documentation 2] Japanese kokai publication hei 10-153979 communique
[patent documentation 3] Japanese Patent Application 2003-135268 communique
[non-patent literature 1] j.Vac.Sci.Techonol.B11 (2) is (1993) p.429-432
[non-patent literature 2] high-efficiency-electro-emission device, Jpn, j, Appl, Phys, vol.36, pp.939
[non-patent literature 3] Electroluminescence, (Japan) Applied Physics, the 63rd volume, No. 6,592 pages
[non-patent literature 4] (Japan) Applied Physics, the 66th volume, No. 5,437 pages
Such a electron source can be lined up a plurality of row (for example horizontal direction) and a plurality of row (for example vertical direction) and form matrix, will dispose in a vacuum and the composing images display unit corresponding to a plurality of fluorophor that each electron source is arranged.Especially be provided with the thin-film electro component of the thermoelectric minor of electronics acceleration layer between lower electrode and upper electrode, device architecture is simpler than field emission formula, and people wait in expectation it is applied in the display unit.
Summary of the invention
When the thin-film electro component was applied to display unit, in order to reduce power consumption, electron source was preferably guaranteed necessary emission current amount with alap driving voltage.And thermoelectric minor electron source, a part of diode current that only flows between lower electrode and the upper electrode becomes emission current, and most of diode current is to not contribution of electronics emission, and therefore, the driving voltage that reduces diode is effective to reducing power consumption.
In addition, reducing driving voltage also is important for the life-span that prolongs electron source.When being the electron source of thermoelectric minor, high driving voltage makes electronics thermalization (trajectoryization) in the insulator that forms the electronics acceleration layer, semiconductor, accelerates the insulator, the semi-conductive deterioration that are caused by hot carrier (hot carrier).Therefore, in order to prolong the life-span of image display device, preferred low driving voltage.
Yet the thin-film electro component makes hot electron transmission and emitting electrons in upper electrode, and therefore, the material of upper electrode adopts the precious metal of the high Ib family of hot electron transmissivity, the platinum group of the 8th family more.These material electronegativity height, for this reason, the work function φ 2 that can be with skew (band offset) φ 2, surface at shown in Figure 2 and the interface electronics acceleration layer has used the situation of other material to compare with upper electrode and has wanted high.The interface can be with skew φ 2 high the time, even apply identical voltage between lower electrode and upper electrode, the effective electric field that is applied to the electronics acceleration layer also can reduce, therefore, the driving voltage that is used to obtain the diode current of needs uprises.And, when the work function φ on surface s is high, also can increase for obtaining the needed diode current of identical emission current, this also becomes the reason that driving voltage uprises.
In addition, when making the attenuation of electronics acceleration layer in order to reduce driving voltage, thermionic energy reduces, and the electron number that passes through the work function potential barrier of upper electrode tails off, and therefore, electronic transmitting efficiency reduces, and is difficult to guarantee that image shows needed emission current amount.
The objective of the invention is to: a kind of image display device is provided, the electronics acceleration layer that its thin-film electro component has lower electrode and upper electrode and is made of insulator, semiconductor between lower electrode and upper electrode, compared with the past, can promote diode current with low threshold voltage, even low-voltage also can be guaranteed the required diode current of electronics emission, realize the image display device that the life-span is long, low in energy consumption.Implementation efficiency height, long electron source of life-span are even but the thin electronics acceleration layer of low voltage drive also can obtain needed emission current amount.Material and the structure and the manufacture method of the thin-film electro component of the best are provided to achieve these goals.
Above-mentioned purpose, realize by such upper electrode, promptly, used the precious metal of platinum group (the 8th family) or Ib family or their stacked film, hybrid films, alloy film, from the interface of electronics acceleration layer until the surface comprises the transistion metal compound of alkali metal oxide, alkali earth metallic compound, the 3rd family～the 7th family.
If representational structure of the present invention is set forth, then as follows.That is,
(1) display unit of the present invention, comprise electron source array and owing to thereby the bombardment from this electron source array institute electrons emitted is energized luminous face, the electronics acceleration layer that above-mentioned electron source has lower electrode and upper electrode and is made of insulator, semiconductor between lower electrode and upper electrode, from above-mentioned upper electrode emitting electrons, the invention is characterized in:
Above-mentioned upper electrode has used precious metal or their stack membrane or the alloy film of platinum group (the 8th family) or Ib family, from the interface of above-mentioned electronics acceleration layer until the surface comprises alkali metal or alkali metal oxide.
(2) display unit of the present invention, comprise electron source array and owing to thereby the bombardment from this electron source array institute electrons emitted is energized luminous face, the electronics acceleration layer that above-mentioned electron source has lower electrode and upper electrode and is made of insulator, semiconductor between lower electrode and upper electrode, from above-mentioned upper electrode emitting electrons, the invention is characterized in:
Above-mentioned upper electrode has used precious metal or their stack membrane or the alloy film of platinum group (the 8th family) or Ib family, from the interface of above-mentioned electronics acceleration layer until the surface comprises alkaline-earth metal or alkaline-earth metals oxide.
(3) display unit of the present invention, comprise electron source array and owing to thereby the bombardment from this electron source array institute electrons emitted is energized luminous face, the electronics acceleration layer that above-mentioned electron source has lower electrode and upper electrode and is made of insulator, semiconductor between lower electrode and upper electrode, from above-mentioned upper electrode emitting electrons, the invention is characterized in:
Above-mentioned upper electrode, used precious metal or their stack membrane or the alloy film of platinum group (the 8th family) or Ib family, from the interface of electronics acceleration layer until the surface comprises the transitional metal or the transition-metal oxide of 3 families～7 families.
The invention is characterized in: the precious metal of the Ib family in (1) to (3) in each the upper electrode and alkali metal, alkaline-earth metal, transition metal form interphase, alloy or their oxide.
The invention is characterized in: the precious metal material of each Ib family is Au or Ag in (1) to (3).
The invention is characterized in: the average film thickness of the precious metal of each Ib family or average grain diameter are smaller or equal to 4nm in (1) to (3).
The invention is characterized in: each upper electrode in (1) to (3), be platinum group (the 8th family) gone up average film thickness stacked or average grain diameter smaller or equal to the stack membrane of the precious metal of the Ib family of 4nm.
Display unit of the present invention, thereby comprise electron source array and by from the bombardment of this electron source array institute electrons emitted and be energized the luminous face of magnetic, the electronics acceleration layer that above-mentioned electron source has lower electrode and upper electrode and is made of insulator, semiconductor between lower electrode and upper electrode, from above-mentioned upper electrode emitting electrons
Above-mentioned upper electrode, be by the alloy of the precious metal of alkali metal or alkali metal oxide and Ib family with the electrode holder of platinum group (the 8th family) at central 3-tier architecture electrode.
The invention is characterized in: as the anode oxide film of electronics acceleration layer use Al or Al alloy, and driving voltage is smaller or equal to 8V.
The invention is characterized in: as the anode oxide film of electronics acceleration layer use Al or Al alloy, and thickness is smaller or equal to 10nm.
By the method that use achieves the above object, can reduce with the insulating barrier of the electronics acceleration layer of electron source array or interface that semiconductor layer joins can be with skew φ 2, can reduce the driving voltage that is used to obtain necessary diode current.
In addition, can reduce the work function of the upper electrode of electron source array, obtain high electronic transmitting efficiency, therefore, can reduce driving voltage.
Under the situation of having used alkali metal, alkali metal oxide, the promoting catalysis of the catalyst activity by improving the precious metal upper electrode just can be made the FED panel that has used the few normal cold cathode of surperficial gas absorption.
In addition, can use thin electronics acceleration layer, can prevent the damage of the insulating barrier that causes by hot carrier with low-voltage, thus life-saving.
Description of drawings
Fig. 1 is with the image display device of the MIM formula thin-film electro component that has used explanation embodiments of the invention 1 schematic plan view as example.
Fig. 2 is the figure of the operating principle of expression thin-film electro component.
Fig. 3 is the figure of the manufacture method of expression thin-film electro component of the present invention.
Fig. 4 is the then figure of Fig. 3 of the manufacture method of expression thin-film electro component of the present invention.
Fig. 5 is the then figure of Fig. 4 of the manufacture method of expression thin-film electro component of the present invention.
Fig. 6 is the then figure of Fig. 5 of the manufacture method of expression thin-film electro component of the present invention.
Fig. 7 is the then figure of Fig. 6 of the manufacture method of expression thin-film electro component of the present invention.
Fig. 8 is the then figure of Fig. 7 of the manufacture method of expression thin-film electro component of the present invention.
Fig. 9 is the then figure of Fig. 8 of the manufacture method of expression thin-film electro component of the present invention.
Figure 10 is the then figure of Fig. 9 of the manufacture method of expression thin-film electro component of the present invention.
Figure 11 is the then figure of Figure 10 of the manufacture method of expression thin-film electro component of the present invention.
Figure 12 is the then figure of Figure 11 of the manufacture method of expression thin-film electro component of the present invention.
Figure 13 is the figure that schematically represents the structure of upper electrode of the present invention.
Figure 14 is the figure that has compared thin-film electro component of the present invention and the composition of the upper electrode of in the past thin-film electro component.
Figure 15 is the figure that schematically represents the variation of band structure of the present invention.
Figure 16 is the figure that has compared the diode current-voltage characteristic of thin-film electro component of the present invention and thin-film electro component in the past.
Figure 17 is the figure that has compared the emission current-voltage characteristic of thin-film electro component of the present invention and thin-film electro component in the past.
Figure 18 be the life characteristic that compared thin-film electro component of the present invention with the figure of the life characteristic of in the past thin-film electro component.
Figure 19 is the figure that has schematically represented the principle that prevents the gas absorption effect of thin-film electro component of the present invention.
Figure 20 be to use the panel of thin-film electro component of the present invention with in the past use the chemical analysis results of residual gas of panel of thin-film electro component.
Figure 21 is the figure that schematically represents other structure of upper electrode of the present invention.
Figure 22 is the figure that has compared the thin-film electro component of other structure of the present invention and the composition of the upper electrode of in the past thin-film electro component.
Figure 23 is the figure that has compared the diode current-voltage characteristic of the thin-film electro component of other structure of the present invention and thin-film electro component in the past.
Embodiment
Below, with reference to the accompanying drawing of embodiment embodiments of the present invention are at length described.At first, as example image display device of the present invention is described with the image display device that has used MIM formula electron source.But, the invention is not restricted to MIM formula electron source, also be effective for the thermoelectric minor that in background technology, illustrates (between lower electrode and upper electrode, being provided with the electron source of electronics acceleration layer).
(embodiment 1)
Fig. 1 is the key diagram of embodiments of the invention 1, is with the image display device that the used MIM formula thin-film electro component schematic plan view as example.In addition, in Fig. 1, main expression is as the plane of the cathode base 10 of a substrate with electron source, and as on a part, being formed with the anode substrate (face substrate) 110 of another substrate of fluorophor, only partly represented black matrix 120 and fluorophor 111,112,113 that mask within it has.
On cathode base 10, be formed with that the lower electrode 11, the formation that constitute the holding wire (data wire) be connected with signal-line driving circuit 50 are connected with scan line drive circuit 60 and with metal film lower layer 16, metal film intermediate layer 17, the metal film upper strata 18 of the scan line 21 of holding wire orthogonal configuration, protect dielectric film (field insulating membrane) 14 and other functional membrane described later etc.In addition, negative electrode (electron emission part) is by being connected with the top bus electrode, and spacer insulator layer and lower electrode 11 stacked upper electrodes (not shown) form, the part emitting electrons of the insulating barrier (tunnel insulation layer) 12 that forms from the coating portion by insulating barrier.Negative electrode of the present invention is characterised in that, begins the surface up to upper electrode 13 at the interface from insulating barrier 12 of upper electrode, the alkali metal oxide that mixed, alkali earth metallic compound, transistion metal compound.
Fig. 2 is the principle key diagram of MIM formula electron source.This electron source is when apply driving voltage Vd between upper electrode 13 and lower electrode 11, when making tunnel insulation layer 12 interior electric fields be 1～10MV/cm left and right sides, near the Fermi level in the lower electrode 11 electronics is because tunnel effect penetrates potential barrier, injection becomes hot electron as the conduction band of the insulating barrier 12 of electronics acceleration layer, flows into the conduction band of upper electrode 13.In these hot electrons, have more than or equal to the energy of the work function φ s of upper electrode 13 and arrive the hot electron on the surface of upper electrode 13, be launched in the vacuum.At this moment, the interface of insulating barrier 12 and upper electrode can be with skew φ 2 low more, the electric field that is applied to insulating barrier 12 with same driving voltage Vd is just strong more, therefore, can obtain to hang down drive threshold voltage.
And, thermionic ceiling capacity can be with skew φ 2 in the insulating barrier for driving voltage Vd deducts, therefore, as long as the band gap width Eg of insulating barrier is worth more than or equal to this, just can suppress the deterioration of the insulating barrier that caused by ionization by collision, be effective for life-saving.
Return Fig. 1,, be formed with the promptly black matrix 120 of light shield layer of the contrast that is used to improve display image and the face that constitutes by red-emitting phosphors 111, green-emitting phosphor 112 and blue emitting phophor 113 at the inner face of anode substrate 110.As fluorophor, for example, redness can be used Y
2O
2S:Eu (P22-R), green can be used ZnS:Cu, Al (P22-g), and blueness can be used ZnS:Ag, Cl (P22-B).Cathode base 10 is kept with predetermined interval by sept 30 with anode substrate 110, after the periphery of viewing area is inserted sealing frame (not shown) sealing, inner vacuum is sealed.
About the embodiment of manufacturing method of anm image displaying apparatus of the present invention, the manufacturing step of the scan electrode of embodiment 1 is described with reference to Fig. 3～Figure 12.At first, as shown in Figure 3, on the cathode base 10 of glass substrate preferably, form the metal film of lower electrode 11 usefulness.As the material of lower electrode 11, use Al class material herein.Using Al class material is because can form the dielectric film of high-quality by anodic oxidation.In addition,, used the mixed Al-Nd alloy of 2 atomic weight % herein to Nd.Film forming is for example used sputter (sputtering) method.Thickness is made as 600nm.
Form the lower electrode 11 (Fig. 4) of striped (stripe) shape after the film forming by graphical step, etching step.The electrode width of lower electrode 11 is different because of size, the resolution of image display device, and the spacing size of its sub-pixel (sub-pixel) roughly is made as about 100～200 microns.The wet etching (wet etching) that carries out is for example used in etching in the mixed aqueous solution of phosphoric acid, acetic acid, nitric acid.This electrode is wide and easy striated structure, and therefore, the graphical usefulness of resist (resist) is undertaken by cheap proximity (proximity) exposure, print process etc.
Then, form the restriction electron emission part, prevent protection insulating barrier 14 and insulating barrier 12 that electric field is concentrated to lower electrode 11 edges.At first, cover the part that becomes electron emission part on the lower electrode shown in Figure 5 11, other parts are carried out anodic oxidation selectively make it thickening, thereby become protection insulating barrier 14 with resist film 25.If establish formation voltage is 100V, then forms the protection insulating barrier 14 of the about 136nm of thickness.Afterwards, remove resist film 25 and with the surperficial anodic oxidation of remaining lower electrode 11.For example, be 4V if establish formation voltage, then on lower electrode 11, form the insulating barrier (tunnel insulation layer) 12 (Fig. 6) of the about 8nm of thickness.Measured as can be known by the x-ray photoelectron spectrophotometric spectra, the band gap of this Al anode oxide film is about 6.4eV.
Then, for example with film (interlayer dielectric) 15 between cambium layer such as sputtering method and metal film (Fig. 7), this metal film is as top bus electrode and the sept electrode that is used for configuration space thing 30, and this top bus electrode is as the feed line to upper electrode 13 feeds.As interlayer film 15, for example can use Si oxide, silicon nitride film etc., use silicon nitride film herein, thickness is made as 100nm.The following effect of this interlayer film 15 performances promptly, exist under the situation of pin hole (pinhole) at the insulating protective layer 14 that is formed by anodic oxidation, is buried this defective, keeps the insulation between connecting up of lower electrode 11 and top bus electrode.
As metal film, pure Al has been used in metal film intermediate layer 17, Cr has been used on metal film lower layer 16, metal film upper strata 18.Therefore the film thickness of pure Al thick meeting reducing cloth line resistance, makes it thick as far as possible.Herein, the thickness of metal film lower layer 16 is made as 100nm, the thickness in metal film intermediate layer 17 is made as 4.5 μ m, the thickness on metal film upper strata 18 is made as 100nm.
Then, the graphical and etching step by the 2nd stage with metal film upper strata 18, metal film intermediate layer 17, is processed into the shape of stripes with lower electrode 11 quadratures.The wet etching that carries out is for example used in the etching of the Cr on metal film upper strata 18 in the ammonium ceric nitrate aqueous solution; The wet etching (Fig. 8) that carries out is for example used in the etching of the pure Al in metal film intermediate layer 17 in the mixed aqueous solution of phosphoric acid, acetic acid, nitric acid.Make the electrode width on metal film upper strata 18 narrower, thereby make metal film upper strata 18 not become the eaves shape than the electrode width in metal film intermediate layer.
Then, by graphical and etching step, metal film lower layer 16 is processed into shape of stripes (Fig. 9) with lower electrode 11 quadratures.Etching for example with in the ammonium ceric nitrate aqueous solution, carry out wet etching carry out.At this moment, one side of metal film lower layer 16 is stretched out from metal film intermediate layer 17, as after step in guarantee the contact site that is connected with upper electrode, opposite side at metal film lower layer 16, the part in metal film upper strata 18 and metal film intermediate layer 17 is formed undercutting (under cut) as mask, after step in form the eaves of separation upper electrode 13.The electrode width of the scan electrode 21 that is formed by metal film lower layer 16, metal film intermediate layer 17, metal film upper strata 18 is different because of size, the resolution of image display device, but in order to realize that low resistanceization makes it wide as far as possible, be made as half, roughly about 300～400 microns more than or equal to trace interval.
Then, film 15 between machined layer, with the electron emission part opening.Electron emission part in pixel 1 lower electrode 11 and with the part of the orthogonal part in the folded space of 2 top bus electrodes of lower electrode 11 quadratures on form.Etching for example can be by having used with CF
4, SF
6(Figure 10) carried out in dry ecthing as the etching gas of main component.
Then, coating alkali metal, alkaline-earth metal, the inorganic salts of transition metal or the aqueous solution of organic salt, and make it dry.By drying, these materials 19 that are present in the aqueous solution are retained with the state on the surface that is adsorbed on insulating barrier 12.As alkali metal, Cs, Rb, K, Na, Li are effective (Figure 11).As salt, can use phosphate, silicate, carbonate, bicarbonate, nitrate, sulfate, acetate, borate, chloride, hydride etc.Alkaline-earth metal has slightly solubility more, but can use for example hydroxide.As alkaline-earth metal, can use Mg, Ca, Sr, Ba etc.As transition metal, W, Mo, Cr that can form water soluble salt etc. is effective.Especially preferredly be, when using the salt that forms with alkali metal, for example when wolframic acid Na, molybdic acid Na etc., alkali doped and transition metal simultaneously.
Then, carry out the film forming of upper electrode 13 by sputtering method etc.As upper electrode 13, the platinum group of the 8th family that thermionic transmitance is high, the precious metal of Ib family are effective.Especially Pd, Pt, Rh, Ir, Ru, Os, Au, Ag or their stack membrane etc. are effective., for example use the stack membrane of Ir, Pt, Au herein, Film Thickness Ratio was made as 1: 2: 3, and thickness for example is made as 3nm (Figure 12).
Then, across sept and members of frame, use frit to calcine, seal between the cathode base of composing images display unit and anode substrate by 400～450 ℃ high-temperature process.At this moment, above-mentioned inorganic salts oxidation, and being mixed in the upper electrode, a part and upper electrode material with alloy phase form alloy, becomes the state of the alkali metal that mixed, alkaline-earth metal, transition metal.For example, carrying out with cesium carbonate under the situation about handling, carbonic acid decomposes, oxidation, becomes cesium oxide, and its part forms AuCs, Au with the Au reaction
5Interphases such as Cs.At this moment, the Ir of platinum group, Pt play a role as catalyst in the decomposition of carbonate, have the effect that promotes decomposition.
So, the ionization tendency alkali metal stronger than upper electrode material, alkaline-earth metal, transition metal, their oxide 20 are present on the interface of upper electrode and insulating barrier 12 (Figure 12).The structural representation of the upper electrode when Figure 13 has been to use AuCs.Form Au-Cs-O alloy 22 be dispersed in Ir, the Pt electrode from the interface of electronics acceleration layer until the structure on surface.Figure 14 represents the composition with the upper electrode of Auger spectrometer (Auger spectroscopy) detection.The composition analysis result of last figure expression electron source in the past, figure below is represented the composition analysis result of the electron source of embodiments of the invention.Be known as below shown in the figure like that, all exist Au-Cs-O up to interface with the electronics acceleration layer.
The electron donability of these metals, metal oxide is strong, as Figure 15 schematically shows, with the interface of insulating barrier 12, forming insulating barrier 12 sides is positive interfacial electric double layer for negative, upper electrode side, dielectric film 12 is offset φ 2 with being with of interface of upper electrode, compares with the situation of the stack membrane that has singly used Ir, Pt, Au and will reduce Δ φ 2.Thus, the drive threshold voltage of negative electrode reduces, and just can obtain the components identical electric current with lower driving voltage.And because the effect of identical electric double layer, the work function on surface reduces Δ φ s, and therefore, electronic transmitting efficiency also can improve.
Figure 16 is that the tunnel insulation layer (thickness 8nm) of the AlNd alloy that will represent in the present embodiment is as the electronics acceleration layer, use Cs, Rb, the carbonate of K, bicarbonate aqueous solution, to the mixed key diagram of diode current-voltage characteristic of MIM formula electron source of cesium oxide, rubidium oxide, potassium oxide of upper electrode.Figure 17 is the key diagram of emission current-voltage characteristic.Compare with the situation of not mixing to upper electrode, when the cesium oxide that mixed, rubidium oxide, potassium oxide, the threshold voltage of diode current descends, and can obtain big element current with low driving voltage.This is because being with of interface is offset φ 2 (being measured as 3.3ev by x-ray photoelectron spectroscopy) by doping cesium oxide, rubidium oxide, potassium oxide, reduced Δ φ 2 (about 1.5eV) as schematically representing among Figure 15.And the threshold voltage of emission current has also descended.Threshold voltage of this expression diode current descends, and because with than the low threshold emissions of threshold voltage 4.8V based on the work function of Au, thereby the work function φ s on surface also as the Δ φ s that descended schematically representing among Figure 15.
Thus, be under the condition of 8nm at Al tunnel insulation layer thickness in the past, show (during peak value) needed emission 100mA/cm in order to obtain image
2, driving voltage must be more than or equal to 8V, and according to the present invention, can realize with the low driving voltage of about 6.5V.Ionization by collision in the insulating barrier of hot carrier, in be offset more than or equal to being with of band gap Eg and the interface when upper electrode has mixed cesium oxide, rubidium oxide, potassium oxide at driving voltage and (being 6.4+3.3-1.5 this moment) time, just take place, therefore, as long as driving voltage is 6.5V, just can prevent ionization by collision.In order to prevent ionization by collision, driving voltage only needs just enough smaller or equal to 8V, therefore, use the anode oxide film of Al as described above,, only the tunnel insulation layer thickness got final product smaller or equal to 10nm to the mixed MIM formula electron source of cesium oxide, rubidium oxide, potassium oxide of upper electrode.
Figure 18 is the life characteristic evaluation result of having added the MIM formula electron source of cesium oxide.Compare with the electron source in the past that downside is represented, in the embodiments of the invention that upside is represented,, also can realize tens thousand of hours life-span even move with the emission more than 20 times.
And, alkali metal oxides such as cesium oxide, rubidium oxide, potassium oxide, as Figure 19 schematically represents, make the co-catalyst effect of catalyst action activation of ultrathin membrane Au etc. of platinum groups such as Ir, Pt, the following degree of 4nm strong, be easy to oxidation Decomposition adsorbed gas, therefore for when forming panel, preventing that gas absorption from also being effective.
Figure 20 represents, has compared the chemical analysis of residual gas in the panel when having or not alkali metal oxide (co-catalyst) to mix.When no co-catalyst, detect organic acid (also comprising hydrocarbon, carbon monoxide etc.), nitride, sulfide, chloride gas, and when co-catalyst is arranged more, compare when not having co-catalyst, reduce to average below 2%.
As other method to the interface of upper electrode and insulating barrier and upper electrode surface alkali doped, alkali metal oxide, such as shown in figure 21, make it to become the alloy by the precious metal of Au-Cs-O alloy 22 alkali metal such as grade or alkali metal oxide and Ib family, the method for the 3-tier architecture electrode in the middle of the electrode 23 of platinum group (8 family) is clipped in also is effective.
Manufacture method as 3 layers of electrode, for example, can make by the following method, promptly, at first by sputter or evaporation alloy (interphase) film forming with precious metal (Au, Ag) Yu the alkali metal (Cs, Rb, K, Na, Li) of Ib family, follow sputter or evaporation platinum group or platinum group alloy, the precious metal (Au, Ag) of last sputter once more or evaporation Ib family and the alloy (interphase) of alkali metal (Cs, Rb, K, Na, Li).Become alkali metal oxide, can easily realize by film forming in oxidizing atmosphere or annealing in the oxygen containing atmosphere at bag after the film forming.In this case, can make alkali metal, alkali metal oxide be present in electronics acceleration layer and surface selectively, can reduce the work function φ s that can be with skew φ 2, surface at interface.Thus, just can realize reducing threshold voltage and these two aspects of raising electronic transmitting efficiency of diode.
When the containing transition metal compound, can also mix by other method.Transition metal and alkali metal, alkaline-earth metal are different, and metallic state is stable, therefore, can be as Fig. 8, as shown in Figure 9, as the bus electrode of top, Cr is used as the material that constitutes wiring; Perhaps with the top bus electrode similarly, be formed on part beyond the electron emission part as exposing metal pattern on the surface.These transition metal, especially Cr, Mo, W etc., when oxidation at high temperature, generate volatile oxide and evaporate, therefore, only need frit (frit) sealing step, just can make transistion metal compound be attached to electron emission part, with upper electrode formation alloy and realize doping with 400～450 ℃ high temperature.Therefore, can omit the applying step of using inorganic salt solution.
Figure 22 represents, the composition of the upper electrode when a conduct example of the present invention that detects by Auger spectrometer has been mixed the Cr oxide, when undoping.The composition of (in the past) when last figure expression undopes the Cr oxide, figure below represented the to mix composition of embodiments of the invention of Cr oxide.In addition, with Au be the upper electrode composition that Ir, Pt, Au have been represented in representative.As shown below, can confirm in upper electrode up to the interface of the insulator Cr oxide that all mixed.
Figure 23 has been to use the key diagram of I-E characteristic of the diode of MIM formula electron source of the present invention.As shown in figure 23, the threshold voltage of the diode current of the element of the Cr oxide that mixed is low, can obtain bigger element current with low driving voltage.Can obtain bigger emission current with low-voltage thus.
Claims (10)
1. image display device, comprise electron source array and owing to thereby the bombardment from this electron source array institute electrons emitted is energized luminous face, the electronics acceleration layer that above-mentioned electron source has lower electrode and upper electrode and is made of insulator, semiconductor between lower electrode and upper electrode, from above-mentioned upper electrode emitting electrons, above-mentioned image display device is characterised in that:
Above-mentioned upper electrode has used precious metal or their stack membrane or the alloy film of platinum group (the 8th family) or Ib family, and from the interface of above-mentioned electronics acceleration layer until the surface comprises alkali metal or alkali metal oxide.
2. image display device, comprise electron source array and owing to thereby the bombardment from this electron source array institute electrons emitted is energized luminous face, the electronics acceleration layer that above-mentioned electron source has lower electrode and upper electrode and is made of insulator, semiconductor between lower electrode and upper electrode, from above-mentioned upper electrode emitting electrons, above-mentioned image display device is characterised in that:
Above-mentioned upper electrode, this upper electrode has used precious metal or their stack membrane or the alloy film of platinum group (the 8th family) or Ib family, comprises alkaline-earth metal or alkaline-earth metals oxide from the interface with above-mentioned electronics acceleration layer up to the surface.
3. image display device, comprise electron source array and owing to thereby the bombardment from this electron source array institute electrons emitted is energized luminous face, the electronics acceleration layer that above-mentioned electron source has lower electrode and upper electrode and is made of insulator, semiconductor between lower electrode and upper electrode, from above-mentioned upper electrode emitting electrons, above-mentioned image display device is characterised in that:
Above-mentioned upper electrode has used precious metal or their stack membrane or the alloy film of platinum group (the 8th family) or Ib family, from the interface of electronics acceleration layer until the surface comprises the transition metal or the transition metal oxide of the 3rd family～the 7th family.
4. according to each described image display device in the claim 1 to 3, it is characterized in that:
The precious metal of the Ib family in the above-mentioned upper electrode and alkali metal, alkaline-earth metal, transition metal form interphase, alloy or their oxide.
5. according to each described image display device in the claim 1 to 3, it is characterized in that:
The precious metal material of above-mentioned Ib family is Au or Ag.
6. according to each described image display device in the claim 1 to 3, it is characterized in that:
The average film thickness of the precious metal of above-mentioned Ib family or average grain diameter are smaller or equal to 4nm.
7. according to each described image display device in the claim 1 to 3, it is characterized in that:
Above-mentioned upper electrode, be platinum group (the 8th family) gone up average film thickness stacked or average grain diameter smaller or equal to the stack membrane of the precious metal of the Ib family of 4nm.
8. image display device, comprise electron source array and owing to thereby the bombardment from this electron source array institute electrons emitted is energized luminous face, the electronics acceleration layer that above-mentioned electron source has lower electrode and upper electrode and is made of insulator, semiconductor between lower electrode and upper electrode, from above-mentioned upper electrode emitting electrons, above-mentioned image display device is characterised in that:
Above-mentioned upper electrode, be by the alloy of the precious metal of alkali metal or alkali metal oxide and Ib family with the electrode holder of platinum group (8 family) at central 3-tier architecture electrode.
9. image display device is characterized in that:
The anode oxide film that to have above-mentioned electronics acceleration layer be Al or Al alloy, and driving voltage is smaller or equal to the electron source array of 8V.
10. image display device is characterized in that:
The anode oxide film that to have above-mentioned electronics acceleration layer be Al or Al alloy, and thickness is smaller or equal to the electron source array of 10nm.
Applications Claiming Priority (4)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP178379/2005 | 2005-06-17 | ||
| JP178747/2005 | 2005-06-20 | ||
| JP111620/2006 | 2006-04-14 | ||
| JP2006111620A JP2007035614A (en) | 2005-06-17 | 2006-04-14 | Image display device |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN101055828A true CN101055828A (en) | 2007-10-17 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN 200610091865 Pending CN101055828A (en) | 2005-06-17 | 2006-06-13 | Image display device |
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| CN (1) | CN101055828A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101814405B (en) * | 2009-02-24 | 2012-04-25 | 夏普株式会社 | Electron emitting element, method for producing electron emitting element and each device using the same |
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2006
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101814405B (en) * | 2009-02-24 | 2012-04-25 | 夏普株式会社 | Electron emitting element, method for producing electron emitting element and each device using the same |
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