EP1153408B1 - Cathode a effet de champ a performances accrues - Google Patents
Cathode a effet de champ a performances accrues Download PDFInfo
- Publication number
- EP1153408B1 EP1153408B1 EP00905117A EP00905117A EP1153408B1 EP 1153408 B1 EP1153408 B1 EP 1153408B1 EP 00905117 A EP00905117 A EP 00905117A EP 00905117 A EP00905117 A EP 00905117A EP 1153408 B1 EP1153408 B1 EP 1153408B1
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- EP
- European Patent Office
- Prior art keywords
- field
- emission cathode
- cathode according
- semiconductor
- microline
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
- H01J1/00—Details of electrodes, of magnetic control means, of screens, or of the mounting or spacing thereof, common to two or more basic types of discharge tubes or lamps
- H01J1/02—Main electrodes
- H01J1/30—Cold cathodes, e.g. field-emissive cathode
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- 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
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
- H01J23/00—Details of transit-time tubes of the types covered by group H01J25/00
- H01J23/02—Electrodes; Magnetic control means; Screens
- H01J23/06—Electron or ion guns
Definitions
- the present invention relates to field effect cathodes (called "field emission array” in English, ie FEA). These cathodes are already used in some types of electronic tubes of large experimental power, such as relativistic magnetrons, vircators ... but also in new tubes of more conventional types such as traveling wave tubes for radar or telecommunication.
- the cathode is formed of at least one network of points comprising a substrate covered with a layer dielectric with cavities, each accommodating an emissive tip in protrusion, a grid placed on the surface of the dielectric layer surrounds less partially the cavities.
- the show electron density can be modulated by modulating the voltage applied to Grid.
- the gate and the substrate-tip assembly separated by the dielectric layer are equivalent to a high capacitance of the order of 10 to 100 pF / mm 2 and the corresponding conductance is of the order of a few tens of mS / mm 2 to 10 GHz.
- a current of 1 ⁇ A / tip can be extracted, the tips having a density of the order of 10 6 to 10 7 per square centimeter.
- the impedance presented by the gate to the modulator that feeds it is essentially real and remains a few tens of ohms, which makes it possible to use a modulator of reasonable power.
- the impedance presented by the gate to the modulator which feeds it becomes very weak because of the reactance of the capacitance which is very weak (0.1 to 1 ⁇ / mm 2 towards 10 GHz by example), which imposes a bandwidth modulator equivalent to that of conventional tubes, at very high power to obtain a satisfactory current intensity.
- the modulator is connected to the gate by a transmission line microwave, usually a microstrip line. Another reason imposing on the modulator a high power is that the signal of modulation applied to the grid is reflected at the transition between the line of transmission and the grid.
- FIG. 1a shows a top view of a cathode field effect of known type.
- Cathode 1 has four networks 2 of sector-shaped tips grouped together on the same support 50 electrically conductive.
- Each network has a conductive substrate referenced 3, a dielectric layer referenced 4 with cavities 5 in which emitters 6, the dielectric layer is surmounted by a grid 7.
- FIG. 1b shows a top view of a cathode field effect of known type.
- Cathode 1 has four networks 2 of sector-shaped tips grouped together on the same support 50 electrically conductive.
- Each network has a conductive substrate referenced 3, a dielectric layer referenced 4 with cavities 5 in which emitters 6, the dielectric layer is surmounted by a grid 7.
- FIG. 1b shows a top view of a cathode field effect of known type.
- each of the networks 2 is done at using microstrip lines 8 each connecting a network of points 2 to one modulator M of power located at a distance.
- microstrip lines 8 each connecting a network of points 2 to one modulator M of power located at a distance.
- the microstrip lines 8 are long, they occupy a good surface more important than peak networks 2.
- the support 50 conductor serves as the conducting plane for microstrip 8 lines. Insulation microstrip lines are referenced 8.2 and the conductive tape 8.3.
- Each microstrip line 8 is electrically connected to a network of points 2 by a conductor 9 secured to one side of the ribbon 8.3 conductor and the other of the grid 7 of the network 2 spikes.
- Modulators M must generate a microwave signal at a high level, in particular because, being located far enough away from arrays of spikes 2, they are connected by lines that generate a strong reflection on the grid side, and because reflections also occur. in advanced networks because of the presence of spikes 6.
- the object of the invention is to propose a cathode which does not have these disadvantages.
- the present invention provides a field effect cathode modulable microwave, formed of at least one network of spikes emissive, capable of emitting electrons with a current density much larger than that of field effect cathodes existing.
- This cathode has the advantage of requiring no modulator of conventional power to control the emission of electrons or line transmission at high level.
- Conventional modulators are expensive, greedy electricity and pose cooling problems.
- the transmission lines pose problems of differential delays phase of the microwave signal and weakening.
- the present invention is a cathode with a microwave modulating field, comprising at least one network of emitting tips, and means for producing a modulation signal microwave to the tips, in which the means for produce the modulation signal include a semiconductor element, characterized in that a micro-line of impedance matching, of length not exceeding several hundred micrometers, is interposed between the semiconductor element and the peak array, for routing the modulation signal of the semiconductor element to the network.
- the microline is a line, in particular of microstrip type or coplanar, whose conducting ribbon is connected at one end to the network of spikes and at the other end to the semiconductor element of modulation.
- the semiconductor modulation element is of transistor type especially MESFET or diode type.
- the conductive ribbon of the microline can be configured in two sections interconnected by a capacitor.
- the microline can also have a polarization function and be connected to a source of polarization.
- At least one of the spike array, the semiconductor element modulation and the microline is discrete.
- At least two elements taken from the network of points, the element modulation semiconductors and microlines are part of the same electrically insulating or semi-insulating support. Both elements can be mounted on one side of the support, the other side of which is coated with conductive layer that serves as a ground plane.
- the network of tips has an electrically insulating or semi-insulating substrate with on one side a conductive or semi-conductive layer, emitting points in electrical contact with the conductive or semiconducting layer, a dielectric layer provided with cavities each housing one of the points, the dielectric layer being surmounted by a conductive grid which surrounds at less partially the cavities.
- the substrate is traversed by at least one hole metallized which helps to electrically connect the tips to the other side of the substrate.
- the metallized hole can be extended by a contact that is reported on a suitable conductive pad of the support.
- the substrate and the dielectric layer can also be traversed by at least one metallized hole which contributes to electrically connect the grid to the other side of the substrate. We can then remove wired links associated with the tips and / or the grid.
- microligne is easily achievable in a form integrated into electrically insulating or semi-insulating support even if the network of points and / or the semiconductor modulation element are discrete.
- the network of spikes, the microligne and the semiconductor element of modulation are integrated on the same semiconductor substrate.
- the semiconductor employed is semi-insulating material such as silicon carbide.
- the microligne can then have a ribbon that extends on one side to form a grid of the spike network and on the other side to form a contact of the semiconductor modulation element.
- Figure 2 shows schematically, with a view to above, a cathode field effect, modulable microwave according the invention.
- the cathode comprises at least one network of R points conventional in itself, means S to produce a modulation signal microwave that controls the emission of electrons and means L for send the signal to the network of points R.
- the means S for producing the signal of microwave modulation comprise a semiconductor element of modulation placed right next to the R-point network, while the means for routing it to the network of spikes R are a short microline introducing a negligible disturbance.
- the microline has not a role of electrical connection between the network of points and the element semiconductor modulation. It also has an adaptation function impedance between the peak array and the semiconductor element of modulation. Moreover, it can also convey at least one voltage of polarization.
- the arrangement of the R-point networks offers a very large number of possibilities. It is possible to focus on a small area a large number of networks of points R, which makes it possible to obtain increased current densities.
- Each network of R points may have optimal dimensions so that there is no or very little disturbance of the modulation signal in the network R peaks which allows to obtain electron beams much more homogeneous than in the past.
- the typical values for such a network of spikes R are of the order of 50 micrometers by 300 micrometers. A spread over a distance of the order of 50 micrometers does not provide any significant disturbance to 10GHz.
- the semiconductor element S of modulation which delivers the microwave modulation signal can be for example a transistor or a diode.
- its area is of the order 500 micrometers by 200 micrometers with an active part by significantly smaller, about 50 micrometers by 200 micrometers.
- the microline L it can have a length of about 100 micrometers or even several hundred micrometers without introducing of significant disturbance.
- FIG. 3a shows in section, an example of field effect cathode according to the invention.
- the network of points R, the microline L and the semiconductor element S of modulation are discrete and integral with the same dielectric support 100.
- the network of points R, the microligne L and the semiconductor element Modulation S are each reported by brazing on a conductive pad respectively 10R, 10L, 10S carried by one of the faces of the dielectric support 100.
- the solder is shown in thick blackened line.
- This dielectric support 100 has an essentially mechanical role but it may be interesting to place on its other main face a coating conductor 101 so as to achieve a local ground plane.
- the microline L is a microstrip line. We could consider that it is a line coplanar and on the figure in section she would have the same profile.
- the line to microstrip L conventionally comprises a conductive plane 10.1 or ground plane, then an electrically insulating or semi-insulating layer 12 then a conductive strip 11.
- the conductive plane 10.1 is attached to the conductive pad 10L of the dielectric support 100.
- the conductive plane 10.1 and the conductive strip 11 may be of nickel or a base alloy titanium, gold, platinum for example.
- the electrically insulating layer or semi-insulating 12 may be ceramic, silica or even carbide of silicon for example.
- the ribbon 11 of the microligne L can be discontinuous and formed of two sections interconnected by a capacitor C reported, for example, between two sections. This capacitor C participates in the impedance matching.
- the network of points R comprises a substrate 13 electrically insulating or semi-insulating with a 13.1 layer on one side conductive or semi-conductive, MP emitting points in contact with the conductive or semiconductor layer 13.1, a layer dielectric 14 provided with cavities 15 each housing one of the points MP, the dielectric layer 14 being surmounted by a conductive grid G which at least partially surrounds the cavities 15.
- the other side of the substrate 13 is coated with a conductive coating 10.2 to join it by soldering on the dielectric support 100.
- the substrate 13 when it is insulating can be for example in glass, alumina, silica and when it is semi-insulating, for example in silicon carbide SiC.
- the materials of the substrate 13 are chosen for their ability to withstand significant voltages, for example of the order of a few hundred volts without damage as well as temperatures high, of the order of 400 ° C for example, these temperatures being reached when the cathode is mounted in a microwave tube that is parboiled to get a good vacuum.
- all incoming materials in the composition in the cathode according to the invention must be able to withstand steaming and must not degas under vacuum.
- the dielectric layer 14 may be silica SiO 2 for example and the gate G and MP points molybdenum for example.
- the semiconductor element S of modulation is in the example of Figure 3a a transistor. More specifically, in this example it is a MESFET type transistor, but of course other types of transistors are usable. It comprises a conductive layer 10.3 for the solder then a substrate 16 of semiconductor material with semi-insulating properties, then a semiconductor coating 18 of type N, realized preferably in two layers 18.1, 18.2, the surface layer 18.1 or contact layer is N + doped and therefore more conductive than the 18.2 background or N-doped active layer, then two ohmic contacts, one of drain Ds and one of source Ss and a Schottky gate contact Gs between ohmic contacts Ds, Ss.
- a passivation layer 21 on the coating 18, it may be silica by example.
- the microligne L is connected at one of its ends to the element modulation semiconductor S, in the example described at its drain Ds, at its other end to the network of points R, in the example at level of the grid G.
- the grid G of the network of points R is brought to a E1 bias voltage and MP peaks at a ground potential.
- the source Ss of the semiconductor element S modulation is connected to a ground potential and the Gs gate receives a modulation HF signal microwave that the semiconductor element will amplify. Connections described above can be achieved by wired wiring (known as English denomination of wire bonding) with 20.1 gold wires for example.
- the semiconductor modulation element S is now a diode, it can for example be of type Gunn or IMPATT. It comprises a first conductive layer K which forms its cathode and that will be soldered on the appropriate conductive pad 10S of the 100 dielectric support. Its anode A is formed by a second layer conductive layer and these two conductive layers A, K are separated by a semiconductor layer 30. Its cathode K is connected to a mass and its anode A at one end of the microligne L.
- Figure 3b differs from the FIG. 3a in that the electrically conductive or semi-conducting layer 13.1 is obtained by surface doping of the semi-insulating layer 13 then made of a semiconductor material with properties semi-insulating materials such as, for example, silicon carbide.
- the MP tips are also made with the semiconductor material to semi-insulating properties rendered semiconductor by doping. Peaks MP could of course be made of an electrically conductor such as molybdenum.
- ribbon 11 is a beach conductor carried by the dielectric support 100, on the face where reported the network of points R and the semiconductor element S of modulation. Its ground plane is formed by the conductive layer 101. It has an anti-radiation screen function. We find the ribbon 11 in two sections and capacitor C.
- the grid G is then deposited in molybdenum, for example ( Figure 4b).
- a masking operation for example by lithography, attack by chemical etching or reactive ion etching (RIE)
- RIE reactive ion etching
- the conductive layer of gate G to form openings 17, then the dielectric layer 14 to form the cavities 15 ( Figure 4c).
- the openings 17 open into the cavities 15.
- the transistor can be realized in a known manner.
- An example embodiment is illustrated in FIGS. 5a to 5h and the transistor obtained corresponds to that shown in Figure 3a.
- silicon SiC or gallium nitride GaN can be obtained by epitaxy whether liquid (LPE), vapor phase (VPE) or by molecular beam (MBE) or ion implantation.
- a trench 20 is made in the contact layer 18.1 in a median zone of the plate 19 by reactive ion etching (FIG. 5c).
- a passivation layer 21 is generally deposited afterwards (FIG. 5d). It may be silica SiO 2 or silicon nitride Si 3 N 4 for example.
- the deposition of the ohmic contacts D s and S s occurs after an etching operation in the passivation layer 21 to the contact layer 18.1, preceded by a masking operation, for example by lithography (FIG. 5e).
- the two substantially identical ohmic contacts D s and S s are then preferably deposited at the same time, by spraying or evaporation in the etched locations. They are usually nickel.
- the resin 25 used in the masking operation is then removed (FIG. 5f).
- the deposition of the Schottky contact G s is carried out separately, again in the case of the trench 20, an etching operation in the passivation layer 21 to the active layer 18.2 preceded by a masking operation for example by lithography ( Figure 5g).
- the contact Schottky G s . titanium for example is deposited by spraying or evaporation in the etched location and is then removed from the resin 27 which was used in the masking operation.
- the electrical connections of the network of R points and the S semiconductor element are in the form of wires 20.1. It may be advantageous to reduce or even delete the number of wired links.
- FIG. 7a, 7b illustrate this configuration.
- a wired link can have a disruptive effect on the electron emission diagram.
- a Wired link is equivalent to a parasitic inductance.
- the S-shaped semiconductor element shown schematically is transistor type. It has three studs: a stud of drain pd, a source pad ps, a grid gate pg each coming into contact electrical with a suitable conductive pad of the dielectric support 100. More particularly the drain pad pd comes into contact with the ribbon 11 of the microline L, the gate pin pg comes into electrical contact with a conductive pad 70 by which is brought the modulation signal to amplify, as for the source pad ps, it comes in contact with a beach conductive 71 connected to the local ground by a metallized hole 72 which passes through the dielectric support 100, for example.
- the pads pd, pg, ps also have a mechanical role of maintaining the S modulation semiconductor element on the dielectric support 100, the mechanical connection can be made by fusion between the pads and the conductive pads.
- This hole 73 is metallized internally and extends to the opposite of the MP points by a contact 74 in the form of a stud conductor 740. It is this pad 740 that will contribute to the electrical connection MP points and mechanical attachment of the network of points R on the dielectric support 100. This pad 740 is in electrical contact with a conductive pad 75 carried by the dielectric support 100, this range conductive 75 being connected in the example to the local mass by any means appropriate.
- the contact 74 of points is not in form of conductive pad as shown in Figure 7b.
- the hole 73 is metallized at its walls, this metallization 78 forms a bottom on the side of the tips MP and leads to the opposite of the tips forming a 741 overhang that comes into contact electrical and mechanical with a suitable conductive pad 75 of dielectric support 100.
- This connection can be soldered.
- this conductive pad 75 is connected to the local ground by a hole metallized 76 which passes through the dielectric support 100 to the ground plane 101.
- the metallization 76 is not hatched so as not to overload the Fig.
- the holes 73 should have a relatively small diameter if the peak density is important in the network. The order of magnitude of their diameter is less than a micrometer. The realization of these holes is delicate. To avoid making too thin holes, you can extend the electrically conductive or semiconductive layer 13.1 which in this variant is continuous from one point to another, by a zone 77 free from MP tip. This variant is illustrated in Figure 7c. We then pierce one or several holes 79 through the electrically insulating or semi-insulating substrate 13 and these holes may be less fine than those in line with MP tips.
- the metallization 80 of the holes is similar to what has just been described for FIGS. 7a or 7b and the contact 74 with points opposite spikes take the form of either stud or overflow.
- the electrical connection of the tip contact 74 may be similar to that described in FIGS. 7a, 7b.
- the mechanical connection of the tip network to the dielectric support 100 can be done as in the examples of FIGS.
- the thickness to be taken consideration is that of the dielectric layer 14 comprising the cavities
- the dielectric layer 14 comprising the cavities 15 and that of the electrically insulating substrate 13 or semi-insulating.
- the orders of magnitude of the thicknesses are as follows: about 1 micrometer for the dielectric layer 14 including the cavities 15 and about 300 micrometers for the electrically insulating substrate 13 or semi-insulating. The energy needed to charge the grid-tip capacity can be reduced for the same emission of electrons.
- FIG. 7d illustrates this configuration.
- One or several holes 82 have been made from the grid to the base of the network of points, through firstly the dielectric layer 14 carrying the cavities And on the other hand the electrically insulating or semi-insulating substrate 13. These holes are metallized and arranged so that the metallization 83 is without electrical contact with the electrically conductive or semi-conductive layer 13.1 point support MP which can then be discontinuous.
- metallization 83 is ends with the contact 81 in the form of a stud or an overflow, the two variants being shown in Figure 7d.
- one of the contacts 81 comes into mechanical and electrical contact with the ribbon 11 of the microligne L and the other (the one in the form of overflow) comes in contact mechanical and electrical with a conductive pad 84 carried by the support dielectric 100 and connected to the polarization source E1.
- the holes can be obtained by RIE engraving. It will be possible to produce the electrically conductive layer 13.1 and / or the grid G nickel which is not attacked during the etching, if this last is performed after the deposition of the dielectric layer 14 and the grid G.
- the metallization of the holes can be carried out in several layers at titanium base, nickel, gold for example. The studs and the overhangs can also be in these materials.
- the microligne L does not serves not only to electrically connect the semiconductor element S of modulation to the network of spikes R. It also has an adaptation function because the semiconductor element S of modulation and the network of points R have typically have very different output impedances.
- the impedance of the semiconductor element can be of the order of a few ohms to a few dozens of ohms while that of the network of spikes of the order of the ohm or the tenth of an ohm.
- the ribbon 11 of the microstrip line will have a geometry that is suitable for performing this adaptation function between the network of points R and semiconductor element S of modulation.
- the thickness of the insulating substrate 12 participates in this adaptation function.
- the thickness of the semiconductor element S modulation is of the order of or slightly larger than that of the network of points R so as not to prevent the extraction of electrons, nor deflect their trajectories. A maximum deviation of the order of ten micrometers is acceptable.
- FIG. 6a represents, in plan view, a cathode according to the invention.
- the modulation semiconductor element S is always a MESFET transistor. Its source S s is brought to ground, its gate G s connected to a bias source E3 receives the microwave modulation signal HF and its drain D s is connected to a first end of the microstrip line L which is shown as a line microstrip.
- the second end of the microline L is connected to the gate G of the tip network R.
- the ribbon geometry of the line L in two sections 11.1, 11.2 connected together by a capacitor C allows the adaptation between the transistor S and the Spike network R.
- the microstrip line L is connected to a source of bias E2 on the side of its first end. This bias applies to the drain D s of the transistor S.
- the wired links at both ends of the microline L are referenced 20.1.
- the peaks MP of the network of points are connected to the mass. This connection is made by an extension of the layer electrically conductive or semiconductive 13.1, without layer cover dielectric, this extension being described in FIG. 7c.
- the grid G of the network of points R is connected to a source of polarization E1.
- Decoupling means C ', L1, L2, L3 have been introduced in a manner quite conventional for a person skilled in the art.
- a capacitor C ' is found between the gate G s of the transistor S and the input of the microwave modulation signal HF, an inductance L3 between the bias source E3 and the gate G s of the transistor S, an inductor L2. between the polarization source E2 and the microstrip line L (drain side D s of the transistor S), an inductance L1 between the bias source E1 and the gate G of the ridge network R.
- FIG. 6b illustrates a cathode according to the invention in which the semiconductor element S modulation is a diode.
- the cathode K of the diode is connected to the mass and the anode A at the first end of the microline L which is also connected to the source of polarization E2.
- SY signal of Synchronization can be injected on the anode A of the diode.
- SY signal of synchronization can be electric and then we place a capacitor of decoupling C "between the anode A and the arrival of the synchronization signal SY.
- the synchronization signal could be optical and in this case the element modulation semiconductor S would be an optical component such as a photodiode.
- the cathode according to the invention comprises a network of points R and a semiconductor element S of discrete modulation, it is possible that the cathode according to the invention is monolithic.
- FIG. 8 which shows such a cathode monolithic. Electrical connections to local ground or to a source polarization were not represented for the sake of clarity, but they can be carried out according to one of the methods described previously.
- the network of points R, the microligne L and the semiconductor element S modulation are integrated on the same substrate 200 semiconductor with semi-insulating properties such as silicon carbide by example. From the point of view of heat evacuation, it gives all satisfaction.
- This common substrate 200 has one of its faces main coated with a conductive layer 201 which serves as a plane of local mass. On the other main face, an area I is determined for at minus a network of points R, a zone II for the microline L and a zone III for the semiconductor element S of modulation.
- zone III the semiconductor element S of modulation and this realization can be done as illustrated in FIGS. 5, the substrate 200 then being equivalent to the substrate 16.
- the zone of points R and this embodiment can be done as illustrated in FIGS. 4, the substrate 200 being then equivalent to the electrically insulating or semi-insulating layer 13.
- zone II the microlignee L is made and its structure is equivalent to that shown in Figure 3b.
- the substrate 200 corresponds virtually to that referenced 100 in Figure 3b.
- the drain of the transistor, the ribbon of the microligne and the grid of the network of spikes can be done during a same step in the same material.
- the passivation layer 21 of the element semiconductor modulation, of dielectric material can extend in zone II by covering the substrate 200 and in zone I by forming the dielectric layer comprising cavities 15.
- Such a cathode with monolithic field effect is very interesting because it is compact, its cost is reduced compared to that a cathode with discrete elements because it uses less materials and its realization takes less time.
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Description
- les figures 1 a, 1 b déjà décrites une vue de dessus et une vue en coupe partielle d'une cathode à effet de champ connue ;
- la figure 2 une vue de dessus d'un exemple de réalisation d'une cathode à effet de champ selon l'invention ;
- les figures 3a, 3b des exemples de réalisation de cathodes à effet de champ selon l'inventions dans lesquelles l'élément semi-conducteur de modulation est un transistor ou une diode ;
- les figures 4a à 4e différentes étapes pour réaliser le réseau de pointes d'une cathode à effet de champ selon l'invention ;
- les figures 5a à 5h différentes étapes pour réaliser l'élément semi-conducteur de modulation d'une cathode à effet de champ selon l'invention ;
- les figures 6a, 6b des exemples de schémas électriques de montage de cathodes à effet champ selon l'invention ;
- les figures 7a à 7d de nouveaux exemples de cathodes selon l'invention dans lesquels certaines liaisons filaires ont été supprimées ;
- les figures 7a à 7d de nouveaux exemples de cathodes selon l'invention dans lesquels certaines liaisons filaires ont été supprimées ;
- la figure 8 un exemple de cathode à effet champ monolithique selon l'invention.
Claims (17)
- Cathode à effet de champ, modulable en hyperfréquence, comportant au moins un réseau (R) de pointes émissives, et des moyens (S) pour produire un signal de modulation hyperfréquence à destination des pointes, dans lequel les moyens pour produire un signal de modulation comprennent au moins un élément semiconducteur , caractérisée en ce qu'une micro-ligne d'adaptation d'impédance (L), de longueur n'excédant pas plusieurs centaines de micromètres, est interposée entre l'élément semiconducteur et le réseau de pointes, pour acheminer le signal de modulation de l'élément semiconducteur au réseau.
- Cathode à effet de champ selon la revendication 1, caractérisée en ce que la microligne (L) est une ligne comportant un ruban (11) conducteur relié à une de ses extrémités au réseau de pointes (R) et à l'autre extrémité à l'élément semi-conducteur (S) de modulation.
- Cathode à effet de champ l'une des revendications 1 ou 2, caractérisée en ce que l'élément semi-conducteur (S) de modulation est de type transistor ou de type diode.
- Cathode à effet de champ selon l'une des revendications 1 à 3, caractérisée en ce que la microligne (L) a un ruban conducteur (11) en deux tronçons (11.1, 11.2) reliés entre eux par un condensateur (C).
- Cathode à effet de champ selon l'une des revendications 1 à 4, caractérisée en ce que la microligne (L) est reliée à une source de polarisation (E2).
- Cathode à effet de champ selon l'une des revendications 1 à 5, caractérisée en ce que la microligne (L) est reliée à l'élément semi-conducteur (S) de modulation et/ou au réseau de pointes (R) par une liaison filaire (20.1).
- Cathode à effet de champ selon l'une des revendications 1 à 6, caractérisée en ce qu'au moins un élément pris parmi le réseau de pointes (R), l'élément semi-conducteur (S) de modulation et la microligne (L) est discret.
- Cathode a effet de champ selon la revendication 7, caractérisée en ce qu'au moins deux éléments pris parmi le réseau de pointes (R), l'élément semi-conducteur (S) de modulation et la microligne (L) sont solidaires d'un même support (100) électriquement isolant ou semi-isolant.
- Cathode à effet de champ selon la revendication 8, caractérisée en ce que les deux éléments sont montés sur une face du support (100) dont l'autre face est revêtue d'une couche conductrice (101) qui sert de plan de masse.
- Cathode à effet de champ selon l'une des revendications 7 à 9, caractérisée en ce que l'élément semi-conducteur de modulation (S) est compatible avec une technique de report par microbossages.
- Cathode à effet de champ selon l'une des revendications 7 à 10, dans laquelle le réseau de pointes (R) comporte un substrat (13) électriquement isolant ou semi-isolant avec sur une face une couche (13.1) conductrice ou semi-conductrice, des pointes émissives (MP) en contact électrique avec la couche conductrice ou semi-conductrice (13.1), une couche diélectrique (14) munie de cavités (15) logeant chacune une des pointes (MP), la couche diélectrique (14) étant surmontée d'une grille (G) conductrice qui entoure au moins partiellement les cavités (15), caractérisée en ce que le substrat (13) est traversé par au moins un trou métallisé qui contribue à relier électriquement les pointes (MP) à l'autre face du substrat (13) électriquement isolant ou semi-isolant.
- Cathode à effet de champ selon l'une des revendications 7 à 11, dans laquelle le réseau de pointes (R) comporte un substrat (13) électriquement isolant ou semi-isolant avec sur une face une couche (13.1) conductrice ou semi-conductrice, des pointes émissives (MP) en contact électrique avec la couche conductrice ou semi-conductrice (13.1), une couche diélectrique (14) munie de cavités (15) logeant chacune une des pointes (MP), la couche diélectrique (14) étant surmontée d'une grille (G) conductrice qui entoure au moins partiellement les cavités (15), caractérisée en ce que le substrat (13) et la couche diélectrique (14) sont traversés par au moins au moins un trou métallisé (82) qui contribue à relier électriquement la grille (G) à l'autre face du substrat (13).
- Cathode à effet de champ selon l'une des revendications 11 ou 12, caractérisée en ce que le trou métallisé (73, 82) se prolonge par un contact électrique (74).
- Cathode à effet de champ selon l'une des revendications 8 à 13, caractérisée en ce que la microligne (L) est intégrée au support (100) électriquement isolant ou semi-isolant.
- Cathode à effet de champ selon l'une des revendications 1 à 7, caractérisé en ce que le réseau de pointes (R), la microligne (L) et l'élément semi-conducteur (S) de modulation sont intégrés sur un même substrat semi-conducteur (200).
- Cathode à effet de champ selon la revendication 15, caractérisée en ce que le substrat semi-conducteur (200) est semi-isolant tel que du carbure de silicium.
- Cathode à effet de champ selon l'une des revendications 15 ou 16, caractérisée en ce que la microligne (L) possède un ruban qui se prolonge d'un côté pour former une grille (G) du réseau de pointes (R) et de l'autre côté pour former un contact (Ds) de l'élément semi-conducteur (S) de modulation.
Applications Claiming Priority (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
FR9901721 | 1999-02-12 | ||
FR9901721A FR2789801B1 (fr) | 1999-02-12 | 1999-02-12 | Cathode a effet de champ a performances accrues |
PCT/FR2000/000346 WO2000048220A1 (fr) | 1999-02-12 | 2000-02-11 | Cathode a effet de champ a performances accrues |
Publications (2)
Publication Number | Publication Date |
---|---|
EP1153408A1 EP1153408A1 (fr) | 2001-11-14 |
EP1153408B1 true EP1153408B1 (fr) | 2005-12-14 |
Family
ID=9541960
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP00905117A Expired - Lifetime EP1153408B1 (fr) | 1999-02-12 | 2000-02-11 | Cathode a effet de champ a performances accrues |
Country Status (7)
Country | Link |
---|---|
US (1) | US6522080B1 (fr) |
EP (1) | EP1153408B1 (fr) |
JP (1) | JP2002536808A (fr) |
KR (1) | KR20010102067A (fr) |
DE (1) | DE60024784T2 (fr) |
FR (1) | FR2789801B1 (fr) |
WO (1) | WO2000048220A1 (fr) |
Families Citing this family (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE602005011475D1 (de) * | 2004-11-09 | 2009-01-15 | Koninkl Philips Electronics Nv | Array von räumlichen lichtmodulatoren und verfahren zur herstellung einer räumlichen lichtmodulationsvorrichtung |
FR2879342B1 (fr) * | 2004-12-15 | 2008-09-26 | Thales Sa | Cathode a emission de champ, a commande optique |
US7794842B2 (en) * | 2004-12-27 | 2010-09-14 | Nippon Steel Corporation | Silicon carbide single crystal, silicon carbide single crystal wafer, and method of production of same |
FR2909801B1 (fr) | 2006-12-08 | 2009-01-30 | Thales Sa | Tube electronique a cathode froide |
ATE515052T1 (de) * | 2007-12-28 | 2011-07-15 | Selex Sistemi Integrati Spa | Feldemissionsbauelement des hochfrequenz- triodentyps und herstellungsprozess dafür |
US8664622B2 (en) * | 2012-04-11 | 2014-03-04 | Taiwan Semiconductor Manufacturing Co., Ltd. | System and method of ion beam source for semiconductor ion implantation |
US8895994B2 (en) | 2012-06-27 | 2014-11-25 | Schlumberger Technology Corporation | Electronic device including silicon carbide diode dies |
Family Cites Families (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE3243596C2 (de) * | 1982-11-25 | 1985-09-26 | M.A.N. Maschinenfabrik Augsburg-Nürnberg AG, 8000 München | Verfahren und Vorrichtung zur Übertragung von Bildern auf einen Bildschirm |
US5268648A (en) * | 1992-07-13 | 1993-12-07 | The United States Of America As Represented By The Secretary Of The Air Force | Field emitting drain field effect transistor |
KR100201553B1 (ko) * | 1995-09-25 | 1999-06-15 | 하제준 | Mosfet를 일체화한 전계방출 어레이의 구조 및 그 제조 방법 |
US5847408A (en) * | 1996-03-25 | 1998-12-08 | Agency Of Industrial Science & Technology, Ministry Of International Trade & Industry | Field emission device |
-
1999
- 1999-02-12 FR FR9901721A patent/FR2789801B1/fr not_active Expired - Fee Related
-
2000
- 2000-02-11 WO PCT/FR2000/000346 patent/WO2000048220A1/fr active IP Right Grant
- 2000-02-11 JP JP2000599054A patent/JP2002536808A/ja active Pending
- 2000-02-11 DE DE60024784T patent/DE60024784T2/de not_active Expired - Lifetime
- 2000-02-11 EP EP00905117A patent/EP1153408B1/fr not_active Expired - Lifetime
- 2000-02-11 US US09/926,008 patent/US6522080B1/en not_active Expired - Lifetime
- 2000-02-11 KR KR1020017010176A patent/KR20010102067A/ko not_active Application Discontinuation
Also Published As
Publication number | Publication date |
---|---|
US6522080B1 (en) | 2003-02-18 |
WO2000048220A1 (fr) | 2000-08-17 |
FR2789801B1 (fr) | 2001-04-27 |
JP2002536808A (ja) | 2002-10-29 |
EP1153408A1 (fr) | 2001-11-14 |
FR2789801A1 (fr) | 2000-08-18 |
KR20010102067A (ko) | 2001-11-15 |
DE60024784T2 (de) | 2006-09-07 |
DE60024784D1 (de) | 2006-01-19 |
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