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In this study, we fabricated nano-capillary emitter arrays for stable ion emission of ionic liquid electrospray thrusters, employing the fabrication of field emitter arrays or gated nano electron sources. A nano-capillary emitter was successfully fabricated with a 100–300 nm capillary diameter, which prevented ionic liquid leakage by significantly increasing the fluidic impedance of the ionic liquid compared to a previously proposed emitter. An ion emission experiment was conducted with 1-ethyl-3-methylimidazolium dicyanamide as the propellant. Ion emission started at a low voltage of 61 V owing to a small gap of approximately 1 μm between the emitter and extractor electrode. The maximum current density was 43 mA cm−2 on the positive side and −13 mA cm−2 on the negative side without leakage of the ionic liquid, which was more than 100 times higher than that of conventional electrospray thrusters. Moreover, we obtained continuous ion emission without current intercepted by the extractor.

We have developed a highly sensitive, compact image sensor that comprises a field emitter array (FEA) and a high-gain avalanche-rushing amorphous photoconductor target, with the ultimate aim of developing an ultrahighly sensitive, compact, high-definition television camera. Double-gated FEs have an advantage of having a compact electron beam focusing system; however, image intensities reproduced by the sensor were nonuniform due to low electron beam current. Furthermore, the simulated electron beam current disagreed with the measured current. The electron beam current characteristics of two types of double-gated, Spindt-type FEs (both with improved electron beam current extraction) are discussed for possible use within the sensor: convex-structured and volcano-structured. A highly accurate simulation model of the image sensor using a double-gated, Spindt-type FE has been examined; the simulated electron beam currents extracted from the double-gated, Spindt-type FE are in agreement with the measured electron beam currents when the initial electron velocity is assumed, thus suggesting that the simulated anode current–anode voltage characteristic conforms to the measured one. For example, the electron beam currents extracted from the convex-structured and volcano-structured FEs when the focusing electrode is placed 0.2 $\mu \text{m}$ below the gate electrode opening at a focusing electrode voltage of 15 V are, respectively, 1.8 and 1.9 times larger than that extracted from the previously used FEs when the focusing electrode is stacked 1.5 $\mu \text{m}$ above the gate electrode. The results show potential for reducing the degradation of the uniformity of the reproduced image’s intensity, and show that the highly accurate simulation model of the sensor is valid to design the double-gated FEAs for the sensor.

Using a fabrication technology of field emitter arrays (FEAs), we have fabricated a high-density emitter array with 5-10 \mu m pitch as ion sources to improve the thrust density of electrospray thrusters. The emitter array is made on a Si wafer and consists of double Nb electrodes with sub-\mu m apertures, where ionic liquid as the propellant is expected to be extracted by applying voltage to the electrodes. This array can realize the emitter density of up to four million/cm2, which is four orders of magnitude higher than that of conventional electrospray thrusters.

Robustness of field emitter arrays (FEA) against high dose rate gamma-ray irradiation was confirmed. The current-voltage characteristics of the FEA were investigated in a vacuum vessel developed for in situ measurements under the irradiation. Although slight increase of the gate current was observed under the irradiation, the insulating layer kept the electrical insulation. As a result, FEA showed the almost identical current-voltage characteristics under the 1.3 kGy h-1 gamma-ray irradiation.

The Minimal Fab system is suitable for low-volume multi-product manufacturing because of its very low initial investment cost. We fabricated volcano-structured Spindt-type field emitter arrays that can be driven in matrix mode for image sensor application by using hybrid process of Minimal Fab system and conventional semiconductor fabrication system. We fabricated 0.6-$\mu \text{m}$-size gated field emitter by using Minimal Maskless lithography system. The planarization using Minimal CMP is performed to prevent break down between matrix type electrode.

We developed an electron optical instrument for evaluating multi-emitters. This device enables us to evaluate both the percentage of active tips and the stability of the emission current from each active tip. Herein, we employed the instrument to observe a volcano-structured Spindt-type field emitter array (FEA) in the photoelectron emission microscopy (PEEM) and field electron emission microscopy (FEEM) modes. Furthermore, we measured the emission current from each active tip in the FEA. Consequently, we found that the number of active tips in the FEA can be considerably increased by aging at a relatively high voltage.

Display Omitted The fabrication of the gated nano electron source is overviewed.Breakthrough in the gate formation process enables multi-gated FEA.Spindt-emitter fabrication is now further improved. Many kinds of attractive new applications, such as image sensors, stationary X-ray sources, and the column-less SEM, are investigated as post field emission displays that use a gated nano electron source. The fabrication of the gated nano electron source is overviewed from the conventional method to the latest one, especially in regarding to the gate formation process. Multi-stacked gate electrode formation using an etch-back method was developed recently, which is a very attractive method for generating a focused electron beam. The traditional Spindt-type emitter fabrication method is also being improved to the one that is easier and applicable to large area substrates. Using a double-layered photoresist as a lift-off layer and using HiPIMS sputtering instead of an e-beam evaporator was proposed. Thin film-type FEA fabrication is also improved to make vertically standing thin film by ion irradiation, which is applicable for making an emitter array on a large sized substrate.

Robustness of field emitter arrays against high-energy X-ray irradiation was demonstrated. The current-voltage characteristics of the field emitter array were investigated in a vacuum chamber connected to an electron accelerator. The electron beam with an energy of 1 MeV was incident onto a tungsten thin plate to produce X-rays. The field emitter array showed the almost identical current-voltage characteristics even under the X-ray irradiation, up to the absorbed dose of 1 kGy/h.

Evaluation of the current density distribution of the electron beam emitted from the volcano-structured, double gated Spindt-type field emitter arrays were performed by numerical simulation in conjunction with analytical approach. By assuming the emitter shape as a part of a hyperboloid, the electric field near the emitter surface could be well estimated even by finite difference method. It was found that the gate height is important to maintain the current density.

Volcano-structured p-type silicon field emitter arrays have been fabricated by etch-back technique and investigated the photoresponse characteristics of electron emission excited by laser pulses. We have observed the current pulses from the device with the same response of the laser pulse.

Volcano-structured double-gated field emitter arrays (VDG-FEAs) with different focusing electrode height have been fabricated and the focusing characteristics for each VDG-FEAs were evaluated in detail. The authors experimentally proved that lowering the focusing electrode was very effective to keep a high emission current and successfully removed the electric field relaxation at the tip during the focusing operation. The anode current of about 1.9μA was maintained for the VDG-FEA with the height of the focusing electrode relative to the extraction electrode, hf=−470nm, even in applying 5V to the focusing electrode, and the current was 84.4 times larger, compared with the sample with hf=220nm under the same focusing condition. It was found that the emitted electrons returned back to the extraction electrode by the potential barrier caused by the low focusing potential below 3V in every sample.

Volcano-structured double-gate field emitter arrays (VDG-FEAs) were fabricated using the etch-back technique. The fabrication process of the VDG-FEA is simple, and the height (hf) of the focusing electrode relative to the extraction gate electrode is easily adjusted by varying the etch-back time without high-resolution lithography. We have fabricated two types of VDG-FEAs with hf = +220 and 0 nm. The focusing characteristic is controlled by tuning hf. The decrease of the anode current is reduced for the VDG-FEA with lower hf under focusing condition producing the same beam spot size.

Electron-emission properties of silicon field-emitter arrays treated with trifluoromethane plasma (Si:C-FEA) were evaluated under H2, CH4, CO, CO2, O2, and C2H4 ambients. Oxidizing gases, including O2 and CO2, make shortened the lifetime. However, reductive gases such as H2 and CH4 lengthened the lifetime longer. On the other hand, C2H4 caused a decrease of the emission current, despite the fact that C2H4 is considered to be one of the reductive gases. Furthermore, emission properties can be recovered by the aging process in an ultrahigh vacuum. This is probably attributable to physisorption and desorption of C2H4 molecules or decomposed molecules onto the emitter surface of the Si:C-FEA.

Volcano-structured double-gate Spindt type field emitter arrays were fabricated using double-layered photoresist as a lift-off layer for the image sensor application. The emitter material that we tested is Ni and Mo/Ni. Electron beam focusing characteristics were evaluated by scanning slit method.

We introduce a suppressor electrode into a micro-sized field emitter to control the emission angle, as an alternative to using an aperture. The suppressor electrode is fabricated between the emission tip and the extractor by using an etch-back technique. The suppressor height is determined to be 100 nm below the tip. This structure is expected to control the emission angle to be narrower when applying a low voltage at the suppressor electrode. The emission characteristics of the fabricated device closely follow the behavior of the simulated results. It is shown that the emission angle is narrowed by applying a negative voltage at the suppressor electrode.

Field emission from individual tips in n- and p-type silicon field emitter arrays (FEAs) has been directly evaluated by using an electrostatic lens projector. The number of the emission spots in the p-type FEA increased with increasing total emission current, and the p-type FEA exhibited better uniformity of the emission than the n-type FEA. In order to improve the emission uniformity, the operation of the FEAs under an atmosphere of ambient gas was executed. The emission uniformity was improved dramatically by exposing C2H4 gas. Also, surface modification of Si field emitters was investigated for damageless vacuum sealing. The vacuum sealing process reduced the emission currents from the nontreated Si FEA by a factor of 10. On the contrary, the emission current from the CHF3-plasma-treated FEA did not change before and after the vacuum sealing process.

In this study, an array of Mo cones for volcano-structured Spindt-type microelectron emitters were fabricated. A recently developed triode high power pulsed magnetron sputtering system was used to control the positive plasma potential and efficiently accelerate ion species. By applying a proper positive voltage to the additional electrode, the authors obtained good cone shapes with high aspect ratios in a water-cooled microcavity structure made of two resist layers, which was previously impossible by conventional vacuum evaporation techniques. The effects of ion acceleration on the alignment of ions along the normal direction, as well as on the stress in the deposited film, are discussed. The former is important for the formation of sharp cones, while the latter is crucial for achieving stable fabrication.

A new fabrication method of Spindt-type field emitters will be presented. In our method, double-layered photoresist is used as a lift-off layer for making an emitter tip. The selection of the emitter material is a key for this process. We selected Ni as the emitter material. We also apply volcano-structured double-gate for the Ni Spindt-type FEA.

We have fabricated a gated niobium nitride field emitter by the transfer mold method. A silicon mold was fabricated by anisotropical etching, followed by oxidation of the mold and deposition of niobium nitride. Niobium nitride thin films were prepared by ion-beam-assisted deposition. After attaching the sample to a glass substrate, the silicon mold was removed by mechanical and wet etching. A molybdenum thin film was then deposited by electron-beam evaporation. Formation of a gate aperture and an insulating silicon dioxide layer were performed by wet etching of only the apex, with other regions being protected by a photoresist layer. An electron emission test of the fabricated emitter array was performed in a high vacuum. We confirmed electron emission of up to 0.1 μA at the emitter–gate voltage of 30 V.

We report optically modulated electron emission from gated p-type silicon field emitter arrays (Si-FEAs). The device's “volcano” structure is designed to control the photoexcitation of electrons by transmitting light through the small gate aperture, thereby minimizing the photogeneration of slow diffusion carriers outside the depletion region in the tip. Compared to that in the dark, the emission current was enhanced by more than three orders of magnitude in the high field region when irradiated with blue laser pulses. Results from the time-resolved measurements of photoassisted electron emission showed that these possess the same response as the laser pulse with no discernible delay. These results indicate that the volcano device structure is effective at eliminating the generation of diffusion carriers and that a fully optimized FEA is promising as a photocathode for producing high-speed modulated electron beams.

The electric field required to emit electrons for boron-doped diamond together with the emission site was estimated using measurement systems that can precisely control the emitter–collector gap and lateral position. Three different types of field emitters were prepared by microwave plasma chemical vapor deposition. Type A was a typical diamond film on a flat silicon substrate, type B was a heteroepitaxial diamond film that was deposited on a (111) oriented platinum substrate, and type C was a pyramidal diamond film fabricated by the transfer mold method. For all the emitters, the voltage required to extract 0.2 nA was measured as a function of the emitter–collector gap, where the device of the emitter–collector configuration is approximated by a pair of parallel plates. The results showed that a strong electric field was applied in front of the emitter. For type B, the emission current distribution was measured by a device in which the collector was an etched needle. It was found that the emission curren...

We fabricated Spindt-type field emitters with four kinds of cathode material (Au, Ni, Pt, and Mo) and estimated the emission characteristics. The Pt emitter showed the best emission characteristics with the lowest operating voltage and the most stable emission among the four kinds of emitters. The difference of the operating voltage among the cathode material is attributed to the emitter shape. The reason the Pt emitter showed stable emission is its inert surface. Pt is a promising material for Spindt-type field emitters from the cone shape, melting point, and inert surface.

Electron emission characteristics of niobium nitride field emitter arrays were investigated as a function of nitrogen composition of niobium nitride. Field emitter arrays with 1024 tips were fabricated by depositing niobium nitride onto the silicon field emitter array, which was fabricated by photolithography and wet etching technique. The electron emission characteristics such as current-voltage characteristics and current fluctuation were measured in ultra high vacuum. The results showed that the field emitter array with mononitride showed lower effective work function and lower current fluctuation. The present results indicated that stoichiometric niobium nitride is preferred composition for field emission cathodes of vacuum microelectronics.

A field emitter (FE) capable of focusing an electron beam is an attractive device for application, such as ultrafine imaging devices, a scanning electron microscope and electron beam lithography. We have developed multi-gated field emitters such as a quadruple-gated FE with a three-stacked electrode lens and a quintuple-gated FE with a four-stacked electrode lens. Both the FEs can focus the electron beam. However, the quintuple-gated FE has a stronger electron convergence than the quadruple-gated FE, and a beam crossover is clearly observed for the quintuple-gated FE.

A new fabrication method of Spindt-type emitters will be presented. In our method, a double-layered photoresist is used as a parting layer, and high power impulse magnetron sputtering (HiPIMS) is used instead of e-beam evaporator for emitter cone formation. The etch-back method, which we have already developed, is adopted to form the multi-gate focusing electrodes on each emitter cone. Our process will make it possible to use a large substrate for Spindt emitter formation.

The concept of column-less SEM using field emitter with a multi-stacked electrostatic lens (multi-gate FE) is proposed. To realize the column-less SEM, we revised fabrication process of the multi-gate FE.

We have been investigating an ultra fine field emission display (FED) and an ultra fine CdTe X-ray image sensor for creating nanovision science. For an ultra fine FED with a sub-micron pixel, we have developed a volcano-structured double-gated field emitter arrays with a capability of focusing electron beam without serous reduction in emission current. For an ultra fine X-ray image sensor, we have proposed and demonstrated a novel CdTe X-ray sensor consisting of a CdTe diode and field emitter array.

We have proposed a simple bending technique for fabricating field emitter arrays (FEAs), based on the ion-induced bending (IIB) effect.[1] In previous studies, we found that the bending angle could be controlled by adjusting the depth of ion irradiation, irrespective of the ion-species.[2,3] IIB could be applied to various materials deposited by a non-specialized sputtering system.[3] Using this technique, we developed a fabrication process for a molybdenum vertical-thin-film (VTF) field emitter array.[2] The IIB technique is a simple bending technique for FEAs because it provides greater freedom of choice in materials, does not require any specialized equipment, and matches conventional microfabrication processes.

Field emitter arrays made of silicon (Si-FEAs) is a possible candidate for the space charge compensation device during ion implantation process for semiconductor devices, because they are free from metal contamination and have less out-gas. When operating in the ion implanter, Si-FEAs suffer from the pressure increase due to out-gassing from resist materials on a silicon wafer. We examined electron emission properties of the Si-FEAs in H2, CH4, CO, O2, or CO2 ambient, which are gases resulting from ion implantation to photoresist. In the work of Gotoh et al. (2006), Si-FEAs treated by CHF3 plasma (Si:C-FEA) were also examined. As a result, it was found that O2 ambient shortened the lifetime of the Si-FEA, but not for the lifetime of the Si:C-FEA. On the other hand, reductive ambient produced good properties of electron emission. In this study, we examined the lifetime of the Si-FEA and the Si:C-FEA in O2 ambient again to reproduce the previous result, and also the lifetime in C2H4 which is also one of the major gases in the implantation ambient.

The HfC-coated Si field emitter arrays (FEA) integrated with poly-Si thin film transistors (TFT) was fabricated in this paper. The emission current was completely controlled by the build-in poly-Si TFT with lightly doped drain (LDD) structure and long channel. The switching voltage of the device is about 10 V, which is lower than that when modulating extraction gate voltage. The TFT integrated FEA is promising for uniform and low power consumption FED system. And furthermore, system on FED panel would be realized by applying current low temperature poly-Si TFT technology.

HfC-coated poly-Si field-emission arrays (FEAs) were produced, and the emission statistics were characterized using a model parameter extraction. The poly-Si, chosen as a substrate, allows the integration of FEAs with control circuits and the scaling up of the fabrication process to larger dimensions, as required by field-emission display applications. The Ar ion sputtering process was used for emitter sharpening, and structures with HfC coatings with different thicknesses were realized. The array field-emission model is built up using equations that describe the electron emission from individual emitters. A general analytical relationship for computing the electric field on the emitter apex was derived. Nonuniform distribution functions within the array for the tip radius and work function are considered. A modified Fowler-Nordheim diagram was used, the emission data current-voltage I-V being represented as ln(I∕V3) as a function of 1∕V. A fast and accurate model parameter extraction is performed using a...

Based on the thin film transistor (TFT)-controlled field emitter array (FEA) technology, the authors successfully fabricated an FEA with a memory function for an ultra-high brightness field emitter display (FED). If an additional TFT for discharge is inserted parallel with the capacitor, the light emitting period can be completely controlled. The brightness of FED can be dynamically controlled by changing light emitting period and pulse height of data line

We have developed a multi-gated field emitter (FE) such as a quadruple-gated FE with a three-stacked electrode lens and a quintuple-gated FE with a four-stacked electrode lens. Both the FEs can focus the electron beam. However, the quintuple-gated FE has a stronger electron convergence than the quadruple-gated FE, and a beam crossover is clearly observed for the quintuple-gated FE.

We have proposed a novel CND: a gated silicon field emission array (Si-FEA) (Ikejiri, 2003). Si-FEA can be an ideal electron source for CND, because the energy distribution expected to be narrow enough to satisfy the above requirements. Furthermore, Si-FEA may eliminate the use of metal. However, the surface of silicon emitter tends to be oxidized when residual gas of a vacuum chamber includes O/sub 2/ gas. While, carbonized silicon emitter is expected to have oxidation resistance, and it doesn't include metal. So in this study, electron emission characteristics of Si-FEA and carbonized Si-FEA (Si:C-FEA) were investigated.

Test arrays of gated Si emitters with N/sub tips/=100 tips have been fabricated. A HfC coating layer was deposited on the tips, showing effectiveness in lowering the operational voltage and improving the uniformity of the array emission. The Si and Si/HfC emitter arrays were measured in high vacuum conditions and after being subject to Ar and O/sub 2/ residual gases with partial pressures in the range 10/sup -4/ to 10/sup -6/ Pa, the evolution in time of the emission properties being recorded. The influence of residual gases on the field emission (FE) properties has been comparatively characterized through model parameter extraction.

In this paper, we have reported the effect of HfC coating and the fabrication of HfC-coated poly-Si FEAs.

A nonlinear least-squares fitting procedure for array model parameter extraction using field emission (FE) data has been developed and extensively applied for Si and Si/HfC-coated arrays with 1024, 4000, and 16 000 tips measured in ultrahigh vacuum conditions. The array FE model is built up using equations that describe the electron emission current from individual emitters of given radius R and work function φ together with nonuniform distribution functions giving the dispersion of these parameters within the array. A combined numerical/analytical approach is used to accurately express the electric field for the actual gated emitter configuration. The FE current is computed through integration of the current density over the emitter tip surface and as a sum of all tip currents in the array. The program, developed as a MATHCAD application using the intrinsic “minerr” routine, extracts array parameters of physical interest and does not make use of “area” and “field enhancement” factors. HfC-coated FE array...

Focuses on the design issues and process calibrations of the fabrication for silicon field emission devices on N type 100 mm diameter silicon wafer. The proposed solution is to fabricate emitter die with 20 arrays of field emitters with each array contains 796 arrays.

Transition metal nitride has a potential for stable emission because of its chemical inertness, low work function and high melting point. We fabricated the NbN/sub x/ thin film field emitter arrays at relatively low temperature (500/spl deg/C) by ion beam assisted deposition technique. This technique can control the nitrogen composition of the film by selecting the deposition parameters. In this work, the relationship between the nitrogen composition of the NbN/sub x/ and emission characteristics was investigated.

To improve the stability and the uniformity of emission currents, we have proposed and fabricated a current-controllable silicon field emitter incorporating a metal-oxide -semiconductor field-effect transistor structure (a MOSFET-structured silicon field emitter). In this device, a built-in MOSFET can control the supply of electrons to the field emitters to stabilize the emission current. The MOSFET-structured emitter is highly compatible with n-MOSFET LSIs in the fabrication processes. Therefore, it is possible to integrate the MOSFET-structured emitter with a driving circuit. We have integrated the Si MOSFET-FEA with n-MOSFET circuits monolithically based on the n-MOSFET process.

ZrN thin film field emitter arrays were fabricated with the ion beam assisted deposition technique, which can control the work function of the ZrN films by choosing the deposition parameters. We investigated the relationship between the work function and the emission stability, and the influence of the ambient gas on the emission stability by introducing the gases of N2 and 02 into the measurement chamber. It was found that the emission stability depended on the work function: the emitters with a lower work function were more stable than those with a higher work function. The dependence is explained qualitatively by the analysis of the Fowler-Nordheim equation. Emission noise increased with the increase of the ambient gas pressure. However, digerenee in the increase of noise between N2 gas and O2 gas was seen. O2 gas severely aflected the emission stability of the ZrN emitter.

We present the electron optical properties of a newly designed microcolumn. The microcolumn consists of an objective lens and an electron gun, which is composed of a microscale field emitter and a condenser lens. An acceleration lens was used as the objective lens. Each component was optimized to maximize its own function while minimizing its impact on the functions of the other components. The current–voltage characteristics of each electrode were evaluated. The current variation characteristics of each electrode indicated that each optimized structure could be used to control the electron beam. The objective lens could also focus the electron beam to a diameter of approximately 40 µm at a working distance of 2 mm and 400× magnification when no acceleration electric field was applied between the microcolumn and the anode.

A vertical thin film field emitter array (VTF-FEA) was integrated with a thin film transistor (TFT) through a simple fabrication process that is compatible with the existing TFT manufacturing process. Specifically, the authors integrated a poly-Si TFT and a previously reported VTF-FEA. The VTF-FEA was fabricated using the ion-induced bending (IIB) technique. The IIB is a technique that can bend a cantilever by ion-beam irradiation and can be used with a wide range of materials. The emission from the TFT-VTF-FEA was controlled from subnanoampere to microampere levels using the built-in TFT. This work demonstrated that VTF-FEAs can be integrated with poly-Si TFTs and other electronic devices, such as metal-oxide semiconductor field effect transistors.

The authors proposed a simple fabrication technique of field emitter array based on a ion-induced bending (IIB) phenomenon. This technique is a very simple two-step process, involving the formation of a cantilever and subsequent ion irradiation. To form a vertical thin film emitter with practical ion dose, however, only a few specific film materials with limited thickness can be used. Therefore, an enhancement method of the IIB phenomenon is necessary. To enhance the IIB phenomenon, the authors proposed the double-layered film method. It was found that the ion-induced bending effect could be extremely enhanced by using a double-layered film method. The required dose could consequently be decreased to less than 5×1015cm−2 in the case of using a heavy element for the cantilever film. This methodology increases the potential of ion-induced bending as a simple fabrication technique for FEA device structures.

A field emitter array (FEA) with four stacked gate electrodes, that is, FEA with a built-in einzel lens, was fabricated using an etch-back technique. In our method, gate hole opening is a self-aligned process; therefore, the axes of electrode holes are well aligned without precise lithography. Emitter tip opening is also a unique process: the tip opening is usually carried out using buffered hydrofluoric (BHF) acid to prevent tip damage. However, in the case of the FEA with a multistacked electrode, BHF etching produces a long undercut under the electrode, particularly under the upper electrode. In our process, the upper lens electrode is used as a photolithography mask when etching silicon dioxide in order to prevent excess undercut. In this paper, the details of fabrication are described.

The ion-induced-bending (IIB) phenomenon was applied for fabricating a field-emitter array (FEA). The IIB method can form a vertical-thin-film (VTF) structure with micron-order height and a high aspect ratio from a thin film. Accordingly, it only needs small quantities of material and uses no specialized equipment. As a result of the optimization of the IIB phenomenon, the apex radius of the VTF was decreased by decreasing the film thickness. The material dependence of the IIB method was investigated, and the authors found that the molybdenum film gives the largest bending angle of the three refractory metals tested. An emission current of 10μA from the Mo-VTF emitter with 1000 tips was obtained at relatively low extraction voltage. Then thus conclude that IIB is a very promising method for fabricating a FEA.