EP0490536A1 - Vacuum microelectronic field-emission device - Google Patents
Vacuum microelectronic field-emission device Download PDFInfo
- Publication number
- EP0490536A1 EP0490536A1 EP91311052A EP91311052A EP0490536A1 EP 0490536 A1 EP0490536 A1 EP 0490536A1 EP 91311052 A EP91311052 A EP 91311052A EP 91311052 A EP91311052 A EP 91311052A EP 0490536 A1 EP0490536 A1 EP 0490536A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- emitter
- substrate
- gate
- collector
- tip
- 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
Links
Images
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
- H01J21/00—Vacuum tubes
- H01J21/02—Tubes with a single discharge path
- H01J21/06—Tubes with a single discharge path having electrostatic control means only
- H01J21/10—Tubes with a single discharge path having electrostatic control means only with one or more immovable internal control electrodes, e.g. triode, pentode, octode
- H01J21/105—Tubes with a single discharge path having electrostatic control means only with one or more immovable internal control electrodes, e.g. triode, pentode, octode with microengineered cathode and control electrodes, e.g. Spindt-type
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
- H01J3/00—Details of electron-optical or ion-optical arrangements or of ion traps common to two or more basic types of discharge tubes or lamps
- H01J3/02—Electron guns
- H01J3/021—Electron guns using a field emission, photo emission, or secondary emission electron source
- H01J3/022—Electron guns using a field emission, photo emission, or secondary emission electron source with microengineered cathode, e.g. Spindt-type
Abstract
Description
- This invention relates to a functional vacuum microelectronic device.
- Recently, with growing development of the fine processing technique, the research and the study for the vacuum microelectronic field-emission devices (VMFE), namely, the cold cathode devices, have become active. Some types of them are studied well because they have various advantageous effects. In the functional vacuum microelectronic field-emission devices, electron emission is carried out by a strong electric field of about 10⁷V developed by concentrating electric lines of force at a tip of an emitter which is processed to have a needle shape such that a curvature of the tip of the emitter is less than hundreds nanometers in order to emit electrons. The tip of the emitter is formed in the vertical direction with respect to the substrate.
- As a new device using the above-mentioned microelectronic field-emission device, a vacuum transistor of the field-emission type disclosed in IEDM 86, 33.1, p776 is proposed. Its structure will be described with reference to drawings. Fig. 24 is a cross-sectional view of a prior art field-emission type vacuum transistor.
- In Fig. 24, silicon Si is used for a
substrate 200. Aconical emitter 201 as an electron emitting portion which is formed by processing thesubstrate 200. On thesubstrate 200, aninsulation layer 202 made of SiO₂ is formed around theemitter 201. Agate 203 and acollector 204 are formed on theinsulation layer 202 at a given intervals. Abias power supply 206 and asignal input portion 205 connected in series are connected between theemitter 200 and thegate 203. Aload resistor 207 and acollector power supply 208 connected in series are connected between theemitter 201 and thecollector 204. - In the above-mentioned structure, when a suitable bias potential is applied between the
gate 203 and theemitter 201 by thebias power supply 206 and a voltage of thesignal input portion 205 is changed,electrons 211 can be emitted from theemitter 201 in accordance with a sum voltage of the bias voltage and an input signal voltage, i.e., a voltage between thegate 203 and theemitter 201. In this state,electrons 211 emitted into a vacuum can be taken into thecollector 204 by application of a sufficient voltage by thecollector power supply 208. As the result, a current flows in theresistor 207, so that a voltage between theterminals output terminal 210 of thecollector 204 can be changed in accordance with the voltage change of thesignal input portion 205. That is, some type of transistor operation or switching operation is achieved. Moreover, in this vacuum microelectronic field-emission device, a high speed operation is possible because electrons runs through a vacuum as against that electrons run through a solid material in the transistor. - However, in the above-mentioned prior art, a semiconductor material is used for the emitter and processing of the
emitter 201 is carried out by anisotropic etching using a unique characteristic of its material. As mentioned, because the material of theemitter 201 is a semiconductor, a work function become higher than that of the metal material, so that a quantity of electron emission becomes small. Accordingly, a signal output level become small, so that there is a problem that its characteristic cannot be utilized sufficiently as a switching device, etc. - Moreover, there is proposed a new device using the above-mentioned small vacuum microelectronic field-emission device is proposed as a three-terminal device shown in Fig. 25, disclosed in the papers of lecture of No. 51 meeting of The Japan Society of Applied Physics, 1990, p1209. Fig. 25 is a plan view of the three-terminal device of a prior art and Fig. 26 shows a cross section taken on line K-K shown in Fig. 25. Hereinbelow will be described its structure with reference to Figs. 25 and 26. The three-terminal device has, on a
substrate 251, an sawtooth-shaped emitter 252, agate 253 formed a given interval apart from a tip of theemitter 252 and the gate portion is formed in a cylindrical-shape, and ananode 254 formed a given interval apart from thegate 253 on the opposite side of thegate 253 from theemitter 252. Grooves are made by removing portions of thesubstrate 251 between theemitter 252 and thegate 252, and between thegate 253 and theanode 254. - The production method of the three-terminal device will be described with reference to Figs. 27A to 27E. As shown in Fig. 27A, a tungsten (W)
film 262 is formed on asubstrate 261. Then, a resist is formed in a given shape on thetungsten film 262. Then, as shown in Fig. 27B, thetungsten film 262 is etched using theresist 263 as a mask. Then, as shown in Fig. 27C, aresist 265 is formed again in a given shape to form portions of thegate 264 into a cylindrical shape. After this, as shown in Fig. 27D, thetungsten film 262 is etched again. As mentioned above, theemitter 266,gate 264, and ananode 267 are formed. Finally, as shown in Fig. 27E, portions of the substrate are removed by etching to form the grooves. - Hereinbelow will be described operation of the tree-terminal device having the above-mentioned structure. In Fig. 25, electrons are emitted from the
emitter 252 when a voltage is applied between theemitter 252 and thegate 253 such that a potential of theemitter 252 is negative and a potential of thegate 253 is positive and an electric field whose intensity is higher than a given value. The amount of emitted electrons can be changed by variation of the applied voltage. The electrons emitted from theemitter 252 can be taken into theanode 254 by applying a sufficient voltage to theanode 254. That is, the amount of electrons flowing into the anode can be changed by variation of a voltage between theemitter 252 and thegate 253. Therefore, a kind of transistor or switching operation is achieved. Moreover, in this vacuum microelectronic field-emission device, a high speed operation is possible because electrons runs through a vacuum space as against that electrons run through a solid material in the transistor. - However, in the above-mentioned prior art structure, positioning is necessary because resist-patterning is carried out twice in the production method. Therefore, because a fine processing technique is required, there is a problem in reproducibility and stability of characteristics of the device.
- The present invention has been developed in order to reduce the above-described drawbacks inherent to the conventional functional vacuum microelectronic field-emission device.
- This invention provides a decrease in operation voltage and an amount of emission of electrons by using a material for the emitter portion whose work function is low. Thus, a level of the output signal can be increased and S/N ratio can be improved. The aim of the invention is to provide a functional vacuum microelectronic field-emission device such that yield is improved because of a simple production method, and thus reliability is improved.
- This invention provides a functional vacuum microelectronic field-emission device having high reproducibility and stability and a production method capable of easy production of the device.
- According to the present invention there is provided a vacuum microelectronic field-emission device comprising:
a substrate;
an emitter portion formed on said substrate having at least a wedge portion extending parallel to said substrate;
a gate portion formed at a corresponding position to said emitter portion, said gate portion being supported by said substrate and being electrically insulated from said emitter portion; and
a collector portion formed at another corresponding position to said emitter portion, said collector portion being supported by said substrate, and being electrically insulated from said emitter portion and said gate portion. - According to the present invention there is also provided a device according to
claim 1, wherein said gate portion is formed a first given distance from the tip of said emitter portion, said collector portion is formed a second given distance from the tip of said emitter portion, said second distance being equal to or larger than said first given distance. - The aims and features of the present invention will become more readily apparent from the following detailed description when taken in conjunction with the accompanying drawings, in which:-
- Fig. 1 is a plan view of a first embodiment of the invention of a functional vacuum microelectronic field-emission device of this invention;
- Fig. 2 shows a cross section taken on line Ib-Ib shown in Fig. 1;
- Figs. 3A-3E show cross sections for showing an example of production processing of the functional vacuum microelectronic field-emission device of the fist embodiment;
- Fig. 4 is a plan view of a second embodiment of the invention of a functional vacuum microelectronic field-emission device;
- Fig. 5 shows a cross section taken on line IVb-IVb shown in Fig. 4;
- Fig. 6 is an enlarged plan view of the functional vacuum microelectronic device of the second embodiment partially shown;
- Figs. 7A-7H show cross sections for showing an example of production processing of the functional vacuum microelectronic field-emission device of the second embodiment;
- Fig. 8 shows a cross section of a functional vacuum microelectronic field-emission device of a third embodiment of the invention;
- Fig. 9 is a plan view of a fourth embodiment of a functional vacuum microelectronic field-emission device of this invention;
- Fig. 10 shows a cross section taken on line IXb-IXb shown in Fig. 9;
- Figs. 11A-11D show cross sections for showing an example of production processing of the functional vacuum microelectronic field-emission device of the fourth embodiment;
- Fig. 12 is a plan view partially showing a functional vacuum microelectronic field-emission device of a fifth embodiment;
- Fig. 13 is a plan view of a functional vacuum microelectronic field-emission device of a sixth embodiment of the invention;
- Fig. 14 shows a cross section taken on line A-A shown in Fig. 13;
- Fig, 15 shows a cross section taken on line B-B shown in Fig. 13;
- Fig. 16 is a plan view of a seventh embodiment of a functional vacuum microelectronic field-emission device of the invention;
- Fig. 17 shows a cross section taken on line C-C shown in Fig. 16;
- Fig. 18 shows a cross section taken on line D-D shown in Fig. 16;
- Figs. 19A-19G show cross sections for showing an example of production processing of a functional vacuum microelectronic field-emission device of an eighth embodiment;
- Figs. 20A-20H show cross sections for showing an example of production processing of a functional vacuum microelectronic field-emission device of a ninth embodiment;
- Fig. 21 is a plan view of a tenth embodiment of the invention of a functional vacuum microelectronic field-emission device;
- Fig. 22 shows a cross section taken on line X-X shown in Fig. 21;
- Figs. 23A-23G show cross sections for showing an example of production processing of a functional vacuum microelectronic field-emission device of an eleventh embodiment;
- Fig. 24 is a cross-sectional view of a prior art field-emission type vacuum transistor;
- Fig. 25 is a plan view of the three-terminal device of a prior art;
- Fig. 26 shows a cross section taken on line K-K shown in Fig. 25; and
- Figs. 27A-27G show cross sections for showing a production processing of the functional vacuum microelectronic field-emission device of the prior art three-terminal device of Fig. 25.
- The same or corresponding devices or parts are designated as like references throughout the drawings.
- Hereinbelow will be described a first embodiment of this invention with reference to Figs. 1 and 2.
- Fig. 1 is a plan view of the first embodiment of the invention of a functional vacuum microelectronic field-emission device of this invention. Fig. 2 shows a cross section taken on line Ib-Ib shown in Fig. 1. Portions with various markings in a plan view correspond to portions marked similarly in the corresponding cross-sectional view throughout the specification.
- As shown in Figs. 1 and 2, an emitter (cathode) 2 is formed on an
insulation substrate 1 made of glass, ceramic, etc. (a metallic substrate can be used also). Theemitter 2 is made of a material having a low work function such as Mo, Ta, W, ZrC, LaB₀, etc. An width (seen in Fig. 1) of at least a portion of the emitter successively changes substantially lineally, so that atip 2a is formed sharply. That is, it is formed to have an wedge portion. On thesubstrate 1, aninsulation layer 3 made of SiO₂, Si₃N₄, Al₂O₃, Ta₂O₅, etc. is formed a given interval apart from the wedge portion of theemitter 2. On theinsulation layer 3, at least agate 4 made of Mo, Ta, Cr, Al, or Au, etc. is formed a given interval apart from thegate 4 on the outside of the wedge portion ofemitter 2. On the theinsulation layer 3, a collector (anode) 5 made of Mo, Ta, Cr, Al, or Au, etc. is formed a given interval apart from thegate 4 on the outside of thegate 4 from the wedge portion ofemitter 2. Theinsulation layer 3 is provided to adjust a height of thegate 4 from thesubstrate 1 to control emission ofelectrons 12 or drawing-out of the electrons from theemitter 2 by thegate 4. However, if thesubstrate 1 is made of a conductive material, theinsulation layer 3 acts as an insulator also. In this embodiment, the gate is formed to have a V-shape.Numerals Numerals emitter 2 andcollector 5.Numeral Numeral 12 are electrons emitted from thetip 2a of theemitter 2. Thetip 2a is formed to have a radii r1 of thetip 2a which is equal to or less than 1000 angstroms. On the other hand, The tip of the V-shaped gate is formed to have a radii r2 thereof which is equal to or larger than 1 micrometer. - Hereinbelow will be described operation of the first embodiment.
- As mentioned above, for example, the
bias power supply 6 and thesignal input portion 7 are connected between theemitter 2 and thegate 4. Acollector power supply 8 and theresistor 9 are connected between theemitter 2 and thecollector 5. This functional vacuum microelectronic field-emission devices are placed in a vacuum space in use. At first, a suitable bias voltage is applied between theemitter 2 andgate 4 by thebias power supply 6. Then, when a suitable voltage is inputted from thesignal input portion 7, the voltage between theemitter 2 and thegate 4 is a combined voltage of the bias voltage and the input signal voltage. Therefore, an electric field whose intensity determined in accordance with the combined voltage is applied to theemitter 2. At this point, electric fields at respective surfaces of theemitter 2 are determined by geometrical position relations between thegate 4 and the respective surfaces of theemitter 2. As a result of a simulation analyzing about such arrangement, it has been known that lines of electric force are concentrated at thesharp tip 2a of the wedge portion of theemitter 2, that is, an electric field is strong at thetip 2a. Electron emission is caused by electric fields at respect points of theemitter 2, which are determined in accordance with the combined voltage. In the wedge-shapedemitter 2, almost allelectrons 12 can be emitted from thetip portion 2a of theemitter 2 because the electric field is strong at thetip portion 2a as mentioned above. In this state, electrons emitted into the vacuum space can be taken into thecollector 5 by application of a sufficient positive voltage to thecollector 5 by thecollector power supply 8. Accordingly, a current flows through theresistor 9, so that a voltage betweenterminals collector 5 in accordance with a voltage change of thesignal input portion 7. Moreover, it is possible that a material having a low work function is used as the material of theemitter 2 because anisotropic etching is not carried out. Therefore, the signal output level can be increased and S/N ratio is improved. - Hereinbelow will be described, an example of production processing of the functional vacuum microelectronic field-emission device of the above-mentioned fist embodiment with reference to Figs. 3A to 3E.
- At first, as shown in Fig. 3A, an
emitter material layer 13 made of Mo, Ta, W, ZrC, and LaB₀, etc. is formed to form theemitter 2 by spatter deposition, or electron beam deposition, etc. on thesubstrate 1 made of glass, or ceramics, etc. with its thickness having 300 nanometer to 1 micrometer. Then, a resist 14 is formed with its thickness having 1 to 2 micrometers to have a given patten on theemitter material layer 13 using the photolithography technique. Then, as shown in Fig. 3B, etching processing is performed to theemitter material layer 13 to have the wedge-shapedemitter 2. At this point, as shown in Fig. 3B, theemitter 2 is so processed that its size is smaller than that of the resist 14 by 1 micrometer by selecting the condition that under-etching occurs. Then, as shown in Fig. 3C, the insulatinglayer 3 made of Sio₂, Si₃N₄, Ta₂O₅, etc. and theconducting layer 15 made of Mo, Ta, Cr, Al, Au, etc. are formed by spatter deposition, electron beam deposition, or CVD, etc. on thesubstrate 1 and the resist 14 with their thicknesses having 300 nanometers to one micrometer and 200 to 500 nanometers respectively. Then, as shown in Fig. 3D, the resist 14 is lifted off together with theinsulation layer 3 and theconductive layer 15 on the resist 14. Then, the resist 16 is formed with a given pattern again. Then, as shown in Fig. 3E, theconductive layer 15 is etched using the resist 16 as a mask and then the resist 16 is removed, so that thegate 4 and thecollector 5 are formed. In Fig. 3E, theemitter 2 has the wedge-shape with asharp tip 2a at its right hand of the drawing. - Then, a voltage of 100 to 300 volts is applied between the
collector 5 and theemitter 2 and a triangle waveform voltage of 0 to 70 volts is applied between theemitter 2 and thegate 4. Then, emission ofelectrons 12 occurs when the applied voltage is more than 50 V, so that the emittedelectrons 12 flow into thecollector 5. That is, a collector current can be suitably controlled in accordance with the voltage change of thegate 4. - Then, a second embodiment of the invention will be described. Fig. 4 is a plan view of the second embodiment of the invention of a functional vacuum microelectronic field-emission device. Fig. 5 shows a cross section taken on line IVb-IVb shown in Fig. 4.
- As shown in Figs. 4 and 5, a
conductive layer 37 made of Mo, Ta, Cr, Al, Au, etc. are formed on thesubstrate 1 made of glass, or ceramics, etc. Theconductive layer 37 has a given shape, for example, a shape such that it extends from a peripheral point toward a center of thesubstrate 1 to provide electrical connection to the center portion of thesubstrate 1. Anemitter 22 made of a material having a low work function such as Mo, Ta, W, ZrC, LaB₀, etc. is formed such that the conductinglayer 37 provides electrical connection to theemitter 22. An width of at least a portion of theemitter 2 successively decrease lineally substantially, so that atip 22a is formed sharply. That is, it is formed to have an wedge portion. In the example shown in drawings, theemitter 22 has a cross-shape such that four projecting portions extend toward four different directions from its center respectively. An width of each projecting portion successively decreases linearly with distance from the center to tip of each projecting portion, so that eachtip 22a is formed sharp. On thesubstrate 1 and theconductive layer 37, aninsulation layer 23 made of SiO₂, Si₃N₄, Al₂O₃, Ta₂O₅, etc. is formed a given interval apart from the wedge portion of theemitter 2 such that it encloses theemitter 22. An end of theconductive layer 37 at the peripheral portion of thesubstrate 37 is exposed to function as a lead terminal. On theinsulation layer 23, agate 24 made of Mo, Ta, Cr, Al, Au, etc. is formed. A portion of thegate 24 extends to another peripheral portion of the substrate in a direction different from that of theconductive layer 37 to have a lead terminal. On theinsulation layer 23, acollector 25 made of Mo, Ta, Cr, Al, Au, etc. is formed a given interval apart from thegate 24 at circumference of thegate 24 on the opposite side of thegate 24 from saidemitter 22. Theconductive layer 37 is used as a lead electrode for providing electrical connection to theemitter 22.Electrons 12 are emitted from thetips 22a of theemitter 22. - Because operation of this embodiment is the same as that of the above-mentioned first embodiment, the description of operation is omitted.
- An example of production processing of the functional vacuum microelectronic field-emission device of the above-mentioned second embodiment will be described with reference to cross-sectional views of Figs. 7A to 7H. Figs. 7A-7H show cross sections for showing an example of production processing of the functional vacuum microelectronic field-emission device of the second embodiment.
- At first, as shown in Fig. 7A, on the
substrate 1 made of glass, or ceramics, etc. theconductive layer 37 made of Mo, Ta, Cr, Al, Au, etc. is formed by the spatter deposition, or the electron beam deposition, etc. on thesubstrate 1 with its thickness having 200 nanometers to 300 nanometers. Then, a resist 38 is formed. Then, as shown in Fig. 7B, etching processing is performed to partially remove theconductive layer 37 using the resist 18 as a mask. Then, anemitter material 39 made of Mo, Ta, Cr, Al, Au, etc. is formed by the spatter deposition, the electron beam deposition, or the CVD, etc. with its thicknesses having 300 nanometers to one micrometers. Then, as shown in Fig. 7C, a resist 40 having a given pattern on theemitter material layer 39 with its thickness of 1-2 micrometers. Then, as shown in Fig. 7D, theemitter material layer 39 is etched to form theemitter 22 and alead terminal 41, theemitter 22 having four projecting portions, each of projecting portions having an wedge shape (in Fig. 4, thelead terminal 41 is not provided). At this point, theemitter material layer 39 is so processed that its peripheral portion is smaller than the resist 40 by up to 1 micrometer by over-etching theemitter material 39. Then, as shown in Fig. 7E, the insulatinglayer 23 made of Sio₂, Si₃N₄, Ta₂O₅, etc. and theconducting layer 42 made of Mo, Ta, Cr, Al, Au, etc. are formed by the spatter deposition, the electron beam deposition, or the CVD, etc. and the resist 20 with their thicknesses having 300 nanometers to one micrometers and 200 to 500 nanometers respectively. Then, as shown in Fig. 7F, the resist 40 is lifted off together with theinsulation layer 23 and theconductive layer 42 formed on the resist 40. Then, the resist 23 is formed with a given pattern again as shown in Fig. 4F. Then, as shown in Fig. 7G, theconductive layer 42 is etched using the resist 23 as a mask to remove the resist 21, so that thegate 24 and thecollector 25 is formed. - Fig. 6 is an enlarged plan view of the functional vacuum microelectronic field-emission device of the second embodiment partially shown. The
tip 22a is formed to have a radii r3 of thetip 22a which is equal to or less than 1000 angstroms. This concentrates lines of electric force at thetip 22a. On the other hand, The tip of the projected portion of thegate 24 is formed to have a radii r4 thereof which is equal to or larger than 1 micrometer. - In the functional vacuum microelectronic field-emission device, the control of a current of the
collector 5 can be carried out readily in accordance with the voltage change of thegate 24 similar to the above-mentioned first embodiment. - Hereinbelow will be described a third embodiment of the invention.
- Fig. 8 shows a cross section of a functional vacuum microelectronic field-emission device of the third embodiment of the invention.
- As shown in Fig. 8, an insulating
layer 58 made of Sio₂, Si₃N₄, Ta₂O₅, etc. is formed on aconductive substrate 51 made of Mo, Ta, Cr, Al, Au, etc. Theinsulation layer 58 has a shape such that portions of theconductive substrate 51 are exposed at a conductingportion 57 and at a leadterminal portion 56 provided at the peripheral portion of theconductive substrate 51. On the conductingportion 57 andinsulation layer 58 of thesubstrate 51, anemitter 52 is formed which is similar to that of the above-mentioned second embodiment and is electrically connected to thesubstrate 1 at the conducting portion. Because structure of theinsulation layer 58,gate 54,collector 54, etc. and operation are the same as those of the above-mentioned second embodiment, the description is omitted. - As mentioned above, according to this invention, application of a voltage between the emitter and the gate and the input of a voltage from the signal input portion causes emitting electrons from the emitter in accordance with the combined voltage. Application of a voltage to the collector can take the emitted electrons so that a voltage at the output terminal of the collector portion can be changed. Moreover, operation voltage can be decreased and the amount of the emitted electrons can be increased because the material whose work function is low can be used as the emitter. Therefore, an output level of the collector is increased, so that S/N ratio is improved. Further, it can be produced by the deposition technique and a simple lithography technique, so that yield and reliability is improved.
- Hereinbelow will be described a fourth embodiment of this invention with reference to drawings.
- Fig. 9 is a plan view of the fourth embodiment of a functional vacuum microelectronic field-emission device of this invention. Fig. 10 shows a cross section taken on line IXb-IXb shown in Fig. 9
- As shown in Figs. 9 and 10, an
emitter 62 is formed on aninsulation substrate 1 made of glass, ceramic, etc. (a metallic substrate can be used also). Theemitter 62 is made of a material having a low work function such as Mo, Ta, W, ZrC, LaB₀, etc. An width of at least a portion of the emitter successively changes lineally, so that atip 62a is formed sharply. That is, it is formed to have an wedge portion. On thesubstrate 1, afirst insulation layer 63 made of SiO₂, Si₃N₄, Al₂O₃, Ta₂O₅, etc. is formed a given interval apart from the wedge portion of theemitter 62. On the first insulatinglayer 63, agate 64 made of Mo, Ta, Cr, Al, or Au, etc. is formed a given interval apart from the wedge portion on the outside of the wedge portion ofemitter 62. On thegate 64, asecond insulation layer 67 made of SiO₂, Si₃N₄, Al₂O₃, Ta₂O₅, etc. is formed. On thesecond insulation layer 67, acollector 65 made of SiO₂, Si₃N₄, Al₂O₃, Ta₂O₅, etc. is formed. Thebias power source 7 and thesignal input portion 8 are connected between thegate 64 and theemitter 62. Thecollector power source 9 and theresistor 10 are connected between theemitter 62 andcollector 65. - Hereinbelow will be described operation in the above-mentioned structure.
- For example, as shown in Fig. 10, the
bias power supply 6, thesignal input portion 7, thecollector power supply 8, and theresistor 9 are connected. A suitable bias voltage is applied between theemitter 62 andgate 64 by thebias power supply 6. Then, a suitable voltage is inputted from thesignal input portion 7. Thus, the voltage between theemitter 62 and thegate 64 is a combined voltage of the bias voltage and the input signal voltage, so that an electric field whose intensity determined in accordance with the combined voltage. At this point, electric fields at respective surfaces of theemitter 62 are determined by geometric position relations between thegate 64 and the respective surfaces of theemitter 62. As a result of a simulation analyzing, it has been known that lines of electric force are concentrated at thesharp tip 62a of the wedge portion of theemitter 62, that is, an electric field at thetip 62a is strong. Electron emission caused by electric fields at respect points of theemitter 62, which are determined in accordance with the combined voltage. In the wedge-shapedemitter 62, almost all ofelectrons 12 can be emitted from thetip portion 62a of theemitter 62 because the electric fields is strong at thetip portion 2a as mentioned above. In this state,electrons 12 emitted into the vacuum space can be taken into thecollector 65 by application of a sufficient positive voltage to thecollector power supply 8. Accordingly, a current flows through theresistor 9, so that a voltage change can be obtained from the terminal 11. That is, an output can be obtained as a change in the output voltage from theoutput terminal 11 of the collector 66 in accordance with a voltage change of thesignal input portion 7. Moreover, it is possible that a material having a low work function is selected as the material of theemitter 2 because anisotropic etching is not carried out. Therefore, the signal output level can be increased and S/N ratio is improved. Therefore, the signal output level can be increased and S/N ratio is improved. - Then, an example of production processing of the functional vacuum microelectronic field-emission device of the above-mentioned fourth embodiment will be described with reference to Figs. 11A to 11D. Figs. 11A-11D show cross sections for showing an example of production processing of the functional vacuum microelectronic field-emission device of the fourth embodiment.
- As shown in Fig. 11A, an
emitter material layer 68 made of Mo, Ta, W, ZrC, and LaB₀, etc. is formed to provide theemitter 62 by the spatter deposition, or the electron beam deposition, etc. on thesubstrate 1 made of glass, or ceramics, etc. with its thickness having 300 nanometer to 1 micrometer. Then, a resist 69 is formed with its thickness having 1 to 2 micrometers to have a given patten on theemitter material layer 68 using the photolithography technique. Then, as shown in Fig. 11B, etching processing is performed to theemitter material layer 68 to have the wedge-shapedemitter 62. At this point, theemitter 62 is so processed that its peripheral portion is smaller than the resist 69 by up to 1 micrometer by selecting the condition that under-etching occurs. Then, as shown in Fig. 11C, the first insulatinglayer 63 made of Sio₂, Si₃N₄, Ta₂O₅, etc. and a conducting layer made of Mo, Ta, Cr, Al, Au, etc., as thegate 64, asecond insulation layer 67 made of the similar material to that mentioned above and a conductive layer made of the similar material to that mentioned above which is to becollector 65 are successively formed by the spatter deposition, the electron beam deposition, or the CVD, etc. on thesubstrate 1 and the resist 69 with their thicknesses having 300 nanometers to one micrometers, 200 to 500 nanometers, 500 nanometers to one micrometers, and 300 to 500 nanometer respectively. Then, as shown in Fig. 11D, the resist 63 is lifted off together with theinsulation layer 63, theconductive layer 64, thesecond insulation layer 67, and theconductive layer 65 formed on the resist 14. Then, the first and second insulation layers 63 and 67 are finally formed into thegate 64 and thecollector 65 by side-etching. In Fig. 11D, theemitter 2 has an wedge shape withtip 2a thereof at its right hand as shown in Fig. 9. - Then, a voltage of 100 to 300 volts is applied to the
collector 65 and a triangle waveform voltage of 0 to 70 volts is applied between theemitter 62 and thegate 64. Then, emission ofelectrons 12 occurs when the applied voltage is more than 50 V, so that the emittedelectrons 12 flow into thecollector 65. That is, the collector current can be suitably controlled in accordance with the voltage change of thegate 64. - Then, a fifth embodiment of the invention will be described. Fig. 12 is a plan view partially showing the functional vacuum microelectronic field-emission device of the fifth embodiment of the invention.
- In this embodiment, as shown in Fig. 12, the
emitter 72 is formed to have a cross-shape such that four projecting portions extend in four different directions from its center respectively. An with of each of projectingportions 72a successively is decreased substantially linearly with distance from the center to atip 72a of each of projecting portions, so that eachtip 72a is formed sharp. The first insulation layer 63 (not shown in Fig. 12, gate 64 (not shown in Fig. 12), the second insulation layer 67 (not shown in Fig. 12), and thecollector 75 are formed such that they enclose theemitter 62. Other structure and operation are the same as that of the above-mentioned first embodiment. - As mentioned above, according to this invention, application of a voltage between the emitter portion and the gate portion and input of a voltage from the signal input portion cause emitting electrons from the emitter portion in accordance with the combined voltage and application of a voltage to the collector portion can take electrons emitted so that a voltage at the output terminal of the collector portion can be changed. Moreover, operation voltage can be decreased and the amount of electron emitted can be increased because the material whose work function is low can be used as the emitter portion. Therefore, an output level of the collector portion is increased, so that S/N ratio is improved. Further, it can be produced by the deposition technique and a simple lithography technique, so that yield and reliability is improved.
- Hereinbelow will be described a sixth embodiment with reference to drawings.
- Fig. 13 is a plan view of a functional vacuum microelectronic field-emission device of the sixth embodiment of the invention. Fig. 14 shows a cross section taken on line A-A shown in Fig. 13. Fig, 15 shows a cross section taken on line B-B shown in Fig. 13.
Numeral 1 is a substrate, numeral 112 is an emitter, numeral 114 is a gate, numeral 113 is an insulation layer, numeral 6 is a bias power supply,numeral 7 is a signal input portion, numeral 8 is a collector power supply,numeral 9 is a resistor,numerals - The
emitter 112 is formed on aninsulation substrate 1 made of glass, ceramic, etc. Theemitter 112 is made of a material, such as Mo, Ta, W, ZrC, or LaB₀, etc. It is formed to have an wedge portion such that an width of at least a portion of theemitter 112 successively changes. Acollector 115 made of Mo, Ta, Cr, Al, or Au, etc. is formed a given interval apart from atip portion 112a of the wedge-shapedemitter 112. Aninsulation layer 113 made of SiO₂, Si₃N₄, Al₂O₃, Ta₂O₅, etc. is formed a given interval apart from theemitter 112 and thecollector 115. Theinsulation layer 113 is provided for adjusting a height ofgate 114 to control of emission of electrons. Thegate 114 made of Mo, Ta, Cr, Al, or Au, is formed on a given portion of theinsulation layer 113. - Hereinbelow will be described operation of the functional vacuum microelectronic field-emission device of the sixth embodiment. For example, the
bias power supply 6 and thesignal input portion 7 are connected between theemitter 112 andgate 114, and ancollector power supply 8 and aresistor 9 are connected between theemitter 112 andcollector 115 as shown in Fig. 13. A suitable bias potential is applied between theemitter 112 and thegate 114 by thebias power supply 6. When a suitable voltage is applied by thesignal input portion 7, a voltage between theemitter 112 and thegate 114 is determined by a sum of the bias voltage and the input signal voltage, namely a combined voltage. Therefore, an electric field whose intensity is determined in accordance with the combined voltage is applied to theemitter 112. Electric fields at each point on the surface of the emitter is determined by a combined electric field determined by geometric positions relation between respective points of the surface of thegate 114. As a result of simulation analysis, it is known that lines of electric force at the wedge-shapedemitter 112 most concentrate at thetip portion 112a and its intensity of the electric field is strong. Emission of electrons occurs in accordance with electric fields at respect portions of theemitter 112 determined by the combined voltage and as mentioned above. Because lines of electric force concentrates at thetip portion 112 of the emitter particularly, it is possible to emit almost all electrons from thetip portion 112a of theemitter 112. Moreover, electrons emitted to the vacuum space can be taken into thecollector 115 by application of a sufficient positive voltage by thecollector power supply 8. As the result, a current flows through theresistor 9, so that a change in voltage between theterminals output terminal 11 of thecollector 114 in accordance with a voltage change of thesignal input portion 7. - Hereinbelow will be described a seventh embodiment of the invention with reference to drawings.
- Fig. 16 is a plan view of the seventh embodiment of a functional vacuum microelectronic field-emission device of the invention. Fig. 17 shows a cross section taken on line C-C shown in Fig. 16. Fig. 18 shows a cross section taken on line D-D shown in Fig. 16.
Numeral 121 is a substrate, numeral 22 is an emitter, numeral 125 is a collector, numeral 124 is a gate, numeral 127 is a groove, and numeral 122a is a tip portion of theemitter 122. - The
emitter 122 is formed on aninsulation substrate 121 made of glass, ceramic, etc. Theemitter 112 is made of a material, such as Mo, Ta, W, ZrC, or LaB₀, etc. It is formed to have an wedge portion such that an width of at least a portion of theemitter 122 successively changes. Ancollector 125 made of Mo, Ta, Cr, Al, or Au, etc. is formed a given interval apart from atip portion 122a of the wedge-shapedemitter 122. The collector made of Mo, Ta, Cr, Al, or Au, etc. is formed a given interval apart from thetip 122a of the wedge-shapedemitter 122. Moreover, agate 124 made of Mo, Ta, Cr, Al, or Au, etc. is formed a given interval apart from theemitter 122 and thecollector 125 at a given portion. At least a surface portion of the substrate 21, where theemitter 122,collector 125, andgate 124 are not formed, and its neighborhood portions are removed to have agroove 127. Thegroove 127 prevents a leak current. Description of its operation is omitted because it is the same as that of the first embodiment. - Hereinbelow will be described an eighth embodiment of the invention with reference drawings. Figs. 19A-19G show cross sections for showing an example of production processing of the functional vacuum microelectronic field-emission device of an eighth embodiment.
- Fig. 19A is a plan view showing a first step of production processing of a functional vacuum microelectronic field-emission device of the eighth embodiment of the invention. Fig. 19B shows a cross section taken on line E-E shown in Fig. 19A. Figs. 19C-19F are crosse-sectional views showing successive processing steps. Fig. 19G is a plan view in a completion step.
Numeral 131 is a substrate, numeral 132 is a conductive layer, numeral 133 is a coat layer, numeral 134 is a photoresist, numeral 135 is an insulation layer, numeral 136 is a gate electrode material, numeral 137 is an emitter, and numeral 138 is an collector. - At first, as shown in Fig. 19A and Fig. 19B, the
conductive layer 132 made of Mo, Ta, W, ZrC, and LaB₀, etc. and thecoat material 133 is formed successively by deposition, or the spatter deposition, etc. on thesubstrate 131 made of glass, or ceramics, etc. On thecoat material 133, thephotoresist 134 is formed by ordinal photolithography technique such that an width of at least a portion successively decreases in direction F and then, the width increases stepwise to an width of thesubstrate 131. Therefore, a constricted portion is made at a given portion of thephotoresist 134. A metal or an insulation material can be used as the above-mentioned coating material. It may be a material capable of withstanding etching processing of theconductive layer 132 in a processing mentioned later and can be removed without corrosion of other materials. Then, as shown in Fig. 19C, thecoating material 133 is etched using thephotoresist 134 as a mask. Then, as shown in Fig. 19C, after removal of thephotoresist 134, theconductive layer 132 is processed using thecoating material 133 as a mask by wet-etching or dry-etching, etc. At this processing, theconductive layer 132 is side-etched to have a form whose size is smaller than pattern shape of thecoating material 133 by a given length as shown in Fig. 19D. Thus, theemitter 137 is processed to have an wedge shape shown in Fig. 19G and thecollector 138 is formed a given interval apart from theemitter 137. Then, as shown in Fig. 19E, on its surface, theinsulation layer 135 made of Sio₂, Si₃N₄, Ta₂O₅, etc. and thegate electrode material 136 made of Mo, Ta, Cr, Al, Au, etc., are successively formed by deposition or the spatter, etc. Then, as shown in Fig. 19F, thecoating material 133 is removed. This causes at the same time theinsulation layer 135 and thegate electrode material 136 formed thecoating material 133 are removed to expose theconductive layer 132. This condition is shown in Fig. 19 G. As mentioned, theconductive layer 132 having the wedge-shape by etching processing is used as anemitter 137. Theconductive layer 132 formed a given interval apart from theemitter 137 is used as thecollector 138. - As mentioned, according to the production method of the functional vacuum microelectronic field-emission device of this embodiment, reproducibility in production is high and stability of the functional vacuum microelectronic field-emission device can be improved because positioning is not necessary because patterning of the resist is performed only once and the position relation between
emitter 137 andgate 136 andcollector 138 which largely effects the characteristic of the functional vacuum microelectronic field-emission device can be controlled by side-etching width in etching processing and self-alignment is utilized. - Hereinbelow will be described a ninth embodiment of the invention with reference drawings. Figs. 20A-20H show cross sections for showing an example of production processing of the functional vacuum microelectronic field-emission device of the ninth embodiment.
- Fig. 20A is a plan view showing a first step on production processing of a function vacuum microelectronic field-emission device of the ninth embodiment of the invention. Fig. 20B shows a cross section taken on line H-H shown in Fig. 20A. Fig. 20C-20G show cross sections showing successive processing steps. Fig. 20H is a plan view in a completion step.
Numeral 141 is a substrate, numeral 142 is a conductive layer, numeral 143 is a coat layer, numeral 144 is a photoresist, numeral 145 is a gate electrode layer, numeral 146 is a groove, numeral 147 is an emitter, and numeral 148 is a collector. - At first, as shown in Fig. 20A and Fig. 20B, the
conductive layer 142 made of Mo, Ta, W, ZrC, and LaB₀, etc. and thecoat material 143 is formed successively with a given thickness by deposition, or the spatter deposition, etc. on thesubstrate 141 made of glass, or ceramics, etc. On its surface, thephotoresist 144 is formed by ordinal photolithography technique such that an width of at least a portion successively decreases in direction J and then, the width increases stepwise to an width of thesubstrate 141. Therefore, a constricted portion is made at a given portion of thephotoresist 144. A metal or an insulation material can be used as the above-mentioned coating material. It may be a material capable of withstanding etching processing of theconductive layer 142 in a processing mentioned later and can be removed without corrosion of other materials. Then, as shown in Fig. 20C, thecoating material 143 is etched using thephotoresist 144 as a mask. Then, as shown in Fig. 20D, after removal of thephotoresist 144, theconductive layer 142 is processed using thecoating material 143 as a mask by wet-etching or dry-etching, etc. At this processing, theconductive layer 142 is side-etched to have a form whose size is smaller than the pattern shape of thecoating material 143 by a given length. Theemitter 147 is processed to have an wedge shape as shown in Fig. 20H showing the completion step and thecollector 148 is formed a given interval apart from the emitter. Then, as shown in Fig. 20E, on its surface, thegate electrode matarial 145 made of Mo, Ta, Cr, Al, Au, etc., is formed on the surface by deposition or the spatter, etc. Then, as shown in Fig. 20F, thecoating material 143 is removed and at the same time, thegate electrode material 145 is removed to expose theconductive layer 142. Then as shown in Fig. 20G, a portion of thesubstrate 141 is etched using theconductive layer 142 and thegate electrode material 145 as a mask. Thegroove 146 is formed between theconductive layer 142 and thegate electrode material 145. This condition is shown in Fig. 20H. As mentioned, theconductive layer 142 having the wedge-shape by etching processing is used as anemitter 147. Theconductive layer 142 formed a given interval apart from theemitter 147 is used as thecollector 148. - As mentioned, according to the production method of the functional vacuum microelectronic field-emission device of this embodiment, reproducibility in production is high and stability of the functional vacuum microelectronic field-emission device can be improved because positioning is not necessary because patterning of the resist is performed only once and the position relation between
emitter 147 andgate 146 andcollector 148 which largely effects the characteristic of the functional vacuum microelectronic field-emission device can be controlled by side-etching width in etching processing and self-alignment is utilized. Moreover, a portion of thesubstrate 141 between theemitter 147 andgate 145 and thecollector 148 is removed, so that the characteristic and the stability of the functional vacuum microelectronic field-emission device is further improved because occurrence of a leak current is prevented. - As mentioned, according to this invention, reproducibility in production and stability of the functional vacuum microelectronic field-emission device can be improved because the gap between the emitter and gate and gate and collector can be made narrow.
- Moreover, in the production processing, the patterning of the resist is performed only once and self-alignment is utilized, so that the functional vacuum microelectronic field-emission device with high reproducibility can be readily obtained. Further, the interval between the emitter and the gate and the interval between the gate and collector are determined by using side-etching width in etching processing, so that there is provided a production method with a very high controlability and the functional vacuum microelectronic field-emission device with stable characteristic.
- Hereinbelow will be described a tenth embodiment of this invention with reference to Figs. 21 and 22.
- Fig. 21 is a plan view of the tenth embodiment of the invention of a functional vacuum microelectronic field-emission device of the tenth embodiment of this invention. Fig. 22 shows a cross section taken on line X-X shown in Fig. 21. Portions with various markings in a plan view correspond to portions marked similarly in the corresponding cross-sectional view throughout the specification.
- As shown in Figs. 21 and 22, an
emitter 152 is formed on aninsulation substrate 151 made of glass, ceramic, etc. Theemitter 152 is made of a material having a low work function such as Mo, Ta, W, ZrC, LaB₀, etc. An width (shown in Fig. 21) of at least a portion of the emitter successively changes lineally, so that atip 152a is formed sharply. That is, it is formed to have an wedge portion. On thesubstrate 151, aninsulation layer 153 made of SiO₂, Si₃N₄, Al₂O₃, Ta₂O₅, etc. is formed a given interval apart from the wedge portion of theemitter 152. On theinsulation layer 153, at least agate 154 made of Mo, Ta, Cr, Al, or Au, etc. is formed a given interval apart from thegate 154 on the outside of the wedge portion ofemitter 152. In this embodiment thegate 154 is formed to have a V-shape. On thesubstrate 151, a collector made of Mo, Ta, Cr, Al, or Au, etc. is formed a given interval apart from thegate 154 on the outside of thegate 154 from the wedge portion ofemitter 152.Numerals Numerals emitter 2 andcollector 155.Numeral Numeral 12 shows electrons emitted from thetip 152a of theemitter 152. Thetip 152a is formed to have a radii r5 of thetip 152a which is equal to or less than 1000 angstroms. On the other hand, The tip of the V-shapedgate 154 is formed to have a radii r6 thereof which is equal to or larger than 1 micrometer. - Hereinbelow will be described operation of the tenth embodiment.
- As mentioned above, for example, the
bias power supply 6 and thesignal input portion 7 are connected between theemitter 152 and thegate 154. Acollector power supply 8 and theresistor 9 are connected between theemitter 152 and thecollector 155. This functional vacuum microelectronic field-emission device is placed in a vacuum space. At first, a suitable bias voltage is applied between theemitter 152 andgate 154 by thebias power supply 6. Then, when a suitable voltage is inputted from thesignal input portion 7, the voltage between theemitter 152 and thegate 154 is a combined voltage of the bias voltage and the input signal voltage, so that an electric field whose intensity determined in accordance with the combined voltage. At this point, electric fields at respective surfaces of theemitter 152 are determined by geometrical position relations between thegate 154 and the respective surfaces of theemitter 152. As a result of a simulation analyzing about such arrangement, it has been known that lines of electric force are concentrated at thesharp tip 152a of the wedge portion of theemitter 152, that is, an electric field is strong at thetip 152a. Electron emission caused by electric fields at respect points of theemitter 152, which are determined in accordance with the combined voltage. In the wedge-shapedemitter 152, almost allelectrons 12 can be emitted from thetip portion 152a of theemitter 152 because the electric field is strong at thetip 152a as mentioned above. In this state,electrons 12 emitted into the vacuum space can be taken into thecollector 155 by application of a sufficient positive voltage to thecollector power supply 8. Accordingly, a current flows through theresistor 9, so that a voltage betweenterminals collector 155 in accordance with a voltage change of thesignal input portion 7. Moreover, it is possible that a material having a low work function is selected as the material of theemitter 2 because anisotropic etching is not carried out. Therefore, the signal output level can be increased and S/N ratio is improved. - Hereinbelow will be described an eleventh embodiment of the invention with reference drawings. Figs. 23A-23G show cross sections for showing an example of production processing of the functional vacuum microelectronic field-emission device of the eleventh embodiment.
- Fig. 23A is a plan view showing a first step on production processing of a function vacuum microelectronic field-emission device of the ninth embodiment of the invention. Fig. 23B shows a cross section taken on line X′-X′ shown in Fig. 23A. Figs. 23C-23F show cross sections showing successive processing steps. Fig. 23G is a plan view in a completion step.
Numeral 161 is a substrate, numeral 167 is a conductive layer, numeral 163 is a coat layer, numeral 166 is a photoresist, numeral 169 is an insulation layer, numeral 168 is another conductive layer, numeral 162 is an emitter, numeral 162a is a tip ofemitter 162, numeral 164 is a gate, and numeral 165 is collector. - At first, as shown in Fig. 23A and Fig. 23B of a cross-sectional view taken on line X′-X′ shown in Fig. 23A, the
conductive layer 167 made of Mo, Ta, W, ZrC, and LaB₀, etc. and thecoat material 163 are formed successively with given thickness by deposition, or the spatter deposition, etc. on thesubstrate 161 made of glass, or ceramics, etc. On its surface, thephotoresist 166 is formed by ordinal photolithography technique such that an width of at least a portion successively changes. A metal or an insulation material can be used as the above-mentioned coating material. It may be a material capable of withstanding etching processing of theconductive layer 168 in a processing mentioned later and can be removed without corrosion of other materials. Then, as shown in Fig. 23C, thecoating material 163 is etched using thephotoresist 166 as a mask. Then, as shown in Fig. 23D, after removal of thephotoresist 166, theconductive layer 167 is processed using thecoating material 143 as a mask by wet-etching or dry-etching, etc. At this processing, theconductive layer 167 is side-etched to have a form whose size is smaller than the pattern shape of thecoating material 163 by a given length. Theemitter 167 is processed to have an wedge shape as shown in Fig. 23G showing the completion step and thecollector 165 is formed with a given interval form theemitter 162. Then, as shown in Fig. 23E, on its surface, the theinsulation layer 169 made of SiO₂, Si₃N₄, Al₂O₃, Ta₂O₅₀, etc. and theconductive layer 168 made of Mo, Ta, Cr, Al, Au, etc., are successively formed on the surface by deposition or the spatter, etc. Then, as shown in Fig. 23F, thecoating material 163 is removed and at the same time, the insulation layer and theconductive layer 168 are removed to expose theconductive layer 167. The resultant form is shown in Fig. 23G. As mentioned, theconductive layer 167 having the wedge-shape by etching processing is used as theemitter 162. Theconductive layer 168 formed on theinsulation layer 169 is used as agate 164. Theconductive layer 167 formed a given interval apart from theemitter 162 is used as thecollector 165. - As mentioned, according to the production method of the functional vacuum microelectronic field-emission device of this embodiment, reproducibility in production is high and stability of the functional vacuum microelectronic field-emission device can be improved because positioning is not necessary because patterning of the resist is performed only once and the position relation between
emitter 162 andgate 164 andcollector 165 which largely effects the characteristic of the functional vacuum microelectronic field-emission device can be controlled by side-etching width in etching processing and self-alignment is utilized. - As mentioned, according to this invention, reproducibility in production and stability of the functional vacuum microelectronic field-emission device can be improved because the gap between the emitter and gate and gate and collector can be made narrow.
- Moreover, in the production processing, the patterning of the resist is performed only once and self-alignment is utilized, so that the functional vacuum microelectronic field-emission device with high reproducibility can be readily obtained. Further, the interval between the emitter and the gate and the interval between the gate and collector are determined by using side-etching width in etching processing, so that there is provided a production method with a very high controlability and the functional vacuum microelectronic field-emission device with stable characteristic.
Claims (18)
- A vacuum microelectronic field-emission device comprising:
a substrate;
an emitter portion formed on said substrate having at least a wedge portion extending parallel to said substrate;
a gate portion formed at a corresponding position to said emitter portion, said gate portion being supported by said substrate and being electrically insulated from said emitter portion; and
a collector portion formed at another corresponding position to said emitter portion, said collector portion being supported by said substrate, and being electrically insulated from said emitter portion and said gate portion. - A vacuum microelectronic field-emission device comprising:
a substrate;
an emitter portion formed on said substrate, said emitter portion having a wedge portion, wherein the width of at least a portion of said wedge portion varies;
an insulation layer formed a first predetermined distance from said emitter portion on said substrate;
a gate portion formed on said insulation layer a second predetermined distance from said emitter portion; and
a collector portion formed a third predetermined distance from said emitter portion on the opposite side of the said gate portion from said emitter portion, said third predetermined distance being larger than said second predetermined distance. - A vacuum microelectronic field-emission device comprising:
a substrate;
an emitter portion formed on said substrate, said emitter portion having a wedge portion, wherein the width of at least a portion of said wedge portion varies;
a collector portion formed a first predetermined distance from said emitter portion, said substrate supporting said collector; and
a gate portion formed a second predetermined distance from said emitter portion, said first predetermined distance being equal to or less than said second predetermined distance and said substrate supporting said gate portion. - A device according to claim 1, wherein said gate portion is formed a first given distance from the tip of said emitter portion, said collector portion is formed a second given distance from the tip of said emitter portion, said second distance being equal to or larger than said first given distance.
- A device according to claim 4, further comprising an insulation layer formed a third given distance from said tip such that it is sandwiched between said gate portion and said substrate.
- A device according to claim 5, wherein said insulation layer extends such that it is further sandwiched between said collector portion and said substrate.
- A device according to claim 4 or 5, further comprising further insulation layer formed on said gate portion, and wherein said collector portion is formed such that said insulation layer is sandwiched between said collector and said gate portions.
- A device according to any one of claims 4 to 7, wherein said substrate has at least one groove between said emitter portion and said collector portion, or between said emitter portion and said gate portion, or between said gate portion and said collector portion.
- A device according to any one of claims 1 to 8, wherein said substrate comprises a conductive material.
- A device according to any one of claims 1 to 8, wherein said substrate comprises an insulation material.
- A device according to any one of the preceding claims, wherein said emitter portion is formed such that the radius (r1) of said tip is equal to or less than 1000 Angstroms.
- A device according to any one of the preceding claims, wherein said gate portion is formed in a V-shape such that said gate portion extends along a portion of the edges of said wedge portion and the tip of said V-shaped gate portion has a radius (r2) equal to or larger than one micrometer.
- A vacuum microelectronic field-emission device comprising:
a substrate;
an emitter portion formed to have at least one wedge portion extending parallel to said substrate, said emitter portion being electrically connected to a conductive layer and being supported by said substrate;
a gate portion formed a first given distance from the tip of said emitter portion such that it substantially surrounds said emitter portion, said gate portion being supported by said substrate and being electrically insulated from said emitter portion; and
a collector portion formed a second given distance from said tip of said emitter portion such that it substantially surrounds said gate portion, said collector portion being supported by said substrate, and being electrically insulated from said emitter and said gate portions. - A device according to claim 13, wherein said emitter portion has a plurality of wedge portions.
- A device according to claim 13 or 14, wherein said conducting layer is formed on said substrate with a given shape; and further comprising:
an insulation layer formed a third given distance from a tip of said emitter, said insulation layer covering said portion of said substrate and a portion of said conductive layer, said insulation layer supporting said gate and collector portions, said insulating layer and said emitter portion being formed such as to expose said conductive layer to cause it to function as a lead terminal. - A device according to claim 13, 14 or 15, wherein said substrate comprises an electrically conductive material, and further comprises an insulation layer formed with a hole to expose a portion of said emitter portion to said substrate.
- A device according to claims 13, 14, 15 or 16, wherein said emitter is formed such that the radius (r3) of said tip is equal to or less than 1000 Angstroms.
- A device according to any one of claims 13 to 17, wherein said gate is formed with a V-shape such that said gate portion extends along a portion of edges of said wedge portion and a tip of said V-shaped gate portion is formed with a radius (r4) equal to or larger than one micrometer.
Applications Claiming Priority (8)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP332411/90 | 1990-11-28 | ||
JP33241290A JPH04206127A (en) | 1990-11-28 | 1990-11-28 | Functional electron emission element |
JP332412/90 | 1990-11-28 | ||
JP33241190 | 1990-11-28 | ||
JP6157491A JP3156265B2 (en) | 1991-03-26 | 1991-03-26 | Method for manufacturing functional electron-emitting device |
JP61574/91 | 1991-03-26 | ||
JP310491/91 | 1991-11-26 | ||
JP31049191A JP2601085B2 (en) | 1990-11-28 | 1991-11-26 | Functional electron-emitting device and method of manufacturing the same |
Publications (2)
Publication Number | Publication Date |
---|---|
EP0490536A1 true EP0490536A1 (en) | 1992-06-17 |
EP0490536B1 EP0490536B1 (en) | 1998-01-14 |
Family
ID=27464057
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP19910311052 Expired - Lifetime EP0490536B1 (en) | 1990-11-28 | 1991-11-28 | Vacuum microelectronic field-emission device |
Country Status (2)
Country | Link |
---|---|
EP (1) | EP0490536B1 (en) |
DE (1) | DE69128702T2 (en) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE19609234A1 (en) * | 1996-03-09 | 1997-09-11 | Deutsche Telekom Ag | Pipe systems and manufacturing processes therefor |
Citations (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0260075A2 (en) * | 1986-09-08 | 1988-03-16 | THE GENERAL ELECTRIC COMPANY, p.l.c. | Vacuum devices |
-
1991
- 1991-11-28 DE DE1991628702 patent/DE69128702T2/en not_active Expired - Fee Related
- 1991-11-28 EP EP19910311052 patent/EP0490536B1/en not_active Expired - Lifetime
Patent Citations (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0260075A2 (en) * | 1986-09-08 | 1988-03-16 | THE GENERAL ELECTRIC COMPANY, p.l.c. | Vacuum devices |
Non-Patent Citations (1)
Title |
---|
JOURNAL OF VACUUM SCIENCE & TECHNOLOGY vol. 8, no. 4, July 1990, NEW YORK pages 3581 - 3585; W.N. CARR ET AL.: 'Vacuum microtriode characteristics' * |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE19609234A1 (en) * | 1996-03-09 | 1997-09-11 | Deutsche Telekom Ag | Pipe systems and manufacturing processes therefor |
WO1997033295A2 (en) * | 1996-03-09 | 1997-09-12 | Deutsche Telekom Ag | Electronic tube system and method of manufacturing same |
WO1997033295A3 (en) * | 1996-03-09 | 1997-12-04 | Deutsche Telekom Ag | Electronic tube system and method of manufacturing same |
Also Published As
Publication number | Publication date |
---|---|
DE69128702D1 (en) | 1998-02-19 |
EP0490536B1 (en) | 1998-01-14 |
DE69128702T2 (en) | 1998-04-23 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
JP3235172B2 (en) | Field electron emission device | |
JP2574500B2 (en) | Manufacturing method of planar cold cathode | |
EP0535953B1 (en) | Field-emission type electronic device | |
US5214346A (en) | Microelectronic vacuum field emission device | |
US5666019A (en) | High-frequency field-emission device | |
US5394006A (en) | Narrow gate opening manufacturing of gated fluid emitters | |
US5780318A (en) | Cold electron emitting device and method of manufacturing same | |
US5543686A (en) | Electrostatic focussing means for field emission displays | |
EP0700063A1 (en) | Structure and method for fabricating of a field emission device | |
US5502314A (en) | Field-emission element having a cathode with a small radius | |
US5469015A (en) | Functional vacuum microelectronic field-emission device | |
US5717278A (en) | Field emission device and method for fabricating it | |
EP0490536A1 (en) | Vacuum microelectronic field-emission device | |
JP3080004B2 (en) | Field emission cold cathode and method of manufacturing the same | |
JPH06196086A (en) | Electric field emission negative electrode and its forming method | |
JP3407289B2 (en) | Electron emission device and driving method thereof | |
JP2601085B2 (en) | Functional electron-emitting device and method of manufacturing the same | |
EP0394742A2 (en) | Superconducting three terminal device and process of fabrication thereof | |
US6771011B2 (en) | Design structures of and simplified methods for forming field emission microtip electron emitters | |
JP3211572B2 (en) | Field emission type electronic device and method of manufacturing the same | |
JP3156265B2 (en) | Method for manufacturing functional electron-emitting device | |
JPH0574327A (en) | Electron emitter | |
JP3468299B2 (en) | Electron emission device | |
KR100274793B1 (en) | Line-type field emission emitter and fabrication method thereof | |
KR100405971B1 (en) | Structure and formation method for focusing electrode in field emssion display |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
PUAI | Public reference made under article 153(3) epc to a published international application that has entered the european phase |
Free format text: ORIGINAL CODE: 0009012 |
|
17P | Request for examination filed |
Effective date: 19911213 |
|
AK | Designated contracting states |
Kind code of ref document: A1 Designated state(s): DE FR GB |
|
17Q | First examination report despatched |
Effective date: 19950915 |
|
GRAG | Despatch of communication of intention to grant |
Free format text: ORIGINAL CODE: EPIDOS AGRA |
|
GRAG | Despatch of communication of intention to grant |
Free format text: ORIGINAL CODE: EPIDOS AGRA |
|
GRAH | Despatch of communication of intention to grant a patent |
Free format text: ORIGINAL CODE: EPIDOS IGRA |
|
GRAH | Despatch of communication of intention to grant a patent |
Free format text: ORIGINAL CODE: EPIDOS IGRA |
|
GRAA | (expected) grant |
Free format text: ORIGINAL CODE: 0009210 |
|
AK | Designated contracting states |
Kind code of ref document: B1 Designated state(s): DE FR GB |
|
REF | Corresponds to: |
Ref document number: 69128702 Country of ref document: DE Date of ref document: 19980219 |
|
ET | Fr: translation filed | ||
PLBE | No opposition filed within time limit |
Free format text: ORIGINAL CODE: 0009261 |
|
STAA | Information on the status of an ep patent application or granted ep patent |
Free format text: STATUS: NO OPPOSITION FILED WITHIN TIME LIMIT |
|
26N | No opposition filed | ||
REG | Reference to a national code |
Ref country code: GB Ref legal event code: IF02 |
|
PGFP | Annual fee paid to national office [announced via postgrant information from national office to epo] |
Ref country code: FR Payment date: 20041109 Year of fee payment: 14 |
|
PGFP | Annual fee paid to national office [announced via postgrant information from national office to epo] |
Ref country code: GB Payment date: 20041124 Year of fee payment: 14 |
|
PGFP | Annual fee paid to national office [announced via postgrant information from national office to epo] |
Ref country code: DE Payment date: 20041125 Year of fee payment: 14 |
|
PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: GB Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES Effective date: 20051128 |
|
PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: DE Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES Effective date: 20060601 |
|
GBPC | Gb: european patent ceased through non-payment of renewal fee |
Effective date: 20051128 |
|
PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: FR Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES Effective date: 20060731 |
|
REG | Reference to a national code |
Ref country code: FR Ref legal event code: ST Effective date: 20060731 |