Nanotechnology – Nalin Kumar, Chenggang Xie, SJ DIAMOND TECHNOLOGY Inc, Applied Nanotech Holdings Inc

Search Patent for “Flat panel display using diamond thin films

Abstract for “Flat panel display using diamond thin films

“A field emission cathode includes a substrate and an adjacent conductive layer. An electrically resistive layer is located adjacent to the conductive layer. The resistive pillar has a substantially flat surface that is spaced from the substrate and nearly parallel to it. An additional layer of diamond is placed on the flat surface the resistive pillar.

Background for “Flat panel display using diamond thin films

Field emitters can be used in a variety of applications, including flat panel displays and vacuum microelectronics. Flat panel flat panel displays that are field emission-based have many advantages over other flat panel displays. These include low power consumption and high intensity, as well as a low projected cost. The current field emitters that use micro-fabricated metal tips are difficult to fabricate and have low yields, which increases the display cost. It is therefore desirable to have a better field emitter material and device structure and a simpler fabrication process. These issues are addressed by this invention.

Understanding the related physics will help you to appreciate the invention. The energy of electrons in a semiconductor or metal surface is generally lower than that of electrons at rest in vacuum. To emit electrons from any material into vacuum, energy must be provided to the electrons within the material. The metal cannot emit electrons if it is not provided with more energy than the electrons at rest in vacuum. You can provide energy through heat or radiation with light. The metal emits electrons when it receives enough energy. There are many types of electron emission phenomena. Thermionic emissions is an electrically charged particle that is emitted from an incandescent substance (such as a vacuum robe, or incandescent lamp). Photoemission is the release of electrons from a substance by using energy provided by radiation, particularly light. Secondary emission is caused by bombardment of a substance using charged particles, such as electrons and ions. The emission of electrons from one solid to the other is called electron injection. Field emission is the emission of electrons by an electric field.

For a metal of the phi value of 4.5 eV, a field of electric potentials of at least 109 V/m is required to produce measurable emission currents. To observe unambiguous field emission, high electric fields are required to be enhanced geometrically at the tip of an emission. This is in order to avoid any dielectric breakdown in electrode support materials. The emission characteristics of a field emitter are affected by its shape. Sharply pointed tips or needles are the best way to obtain field emission. A typical structure for a lithographically-defined sharp tip for a Cold Cathode is composed of small emitter structures of approximately 1-2 m in height and submicron (50nm) emitting points. The silicon dioxide layer separates them from the 0.5-m thick metal grid. Stanford Research Institute (‘SRI”) has shown that vacuum electronics can produce 100?A/tip with a cathode bias of 100-200V. To produce such fine tips, however it is necessary to have extensive fabrication facilities in order to precisely tailor the emitter into a conical form. Because the cone size of the lithographic equipment is restricted, it makes it difficult to create large-area field emitters. Fine feature lithography is difficult on large substrates, as required for flat panel display types applications.

“According to the invention, a flat panel LCD is provided that incorporates diamond film to increase image intensity at low costs.”

“The present invention provides for a flat panel LCD with a diamond field emission catalyst to attain the above advantages.”

“Vacuum diodes can be fabricated on a substrate using standard fabrication techniques such as deposition, masking, and etching.”

Referring to FIG. 1. The drawings show a starting step, a blanket 100 of 5000. Thick chromium, which can also be aluminum (Al), molybdenum [Mo], or titanium (Ti), is deposited using conventional deposition techniques such as evaporation or sputtering. Next, a layer is applied of photo resist by spinning to a thickness between 1 and 2 m. The chromium layer 100 can be delineated using mask exposure. The 100th resist layer is used as a mask for the 100 chromium layers 100. The chromium 100 layer serves two purposes: it forms the addressing lines for field emitters and the base. Different applications determine the dimensions of the base and the addressing lines. Display applications have a pillar size of approximately 100 m to 250m, and a line of about 25m. Vacuum microelectronic devices, such as high-power, high frequency amplifiers, have a feature size of several microns. Final, any residual resist is removed after etching (see FIG. 2).”

“FIG. “FIG. The metal mask deposition technique is used to deposit the conductive pillars 300 onto the bases. The pillars 300 are slightly smaller than the bases. If the base measures 120 m in width, then the optimal size for the pillars 300 is 100 m. This reduces the need to align the metal mask 304 to substrate. It also results in a lower manufacturing cost. Device parameters like operating voltage, spacer size and gap between anode and cathode determine the height of the 300 pillars. Here, pillars of 10 m height are used. The FN theory of field emissions states that the emission current is sensitive to the distance between the anode cathode, cathode, and the surface conditions of cathode. The thickness of thin film cathodes can be controlled using conventional technologies like sputtering and evaporation. However, uniformity of the emission current across large areas is still a problem. If the material has a 4.5 eV working function and the applied electric field is 100 MV/m, then a 1% difference between the anode and cathode will result in 10% variation in the emission current. The 300 pillars are made of resistive material to increase the uniformity in the emission. A resistive material adjusts the potential between the anode and cathode. The potential across the gap between cathode and anode is smaller the higher the pillar. If the pillars are made of a suitable resistor material, the emission current can be reduced or eliminated by reducing the difference in pillar height. The resistive pillars 300 also serve as a current control layer. Because of surface conditions such as contamination, roughness and flatness, some emitters have a higher emission current than others. The resistive pillar 300 is present so that the potential drop across pillars with higher emission currents is greater than the drop across pillars with lower emission currents. The optimal thickness of the resistive 101 layer in the 10 m high pillars 300 are 5 m.

Referring to FIG. “Referring still to FIG. Layer 302’s function is to dissipate heat from the emission current.

“In FIG. 3. The diamond thin film 303 was deposited using room temperature deposition technology, such as laser ablation through holes in the metal mask. 304. The thickness of diamond 303 is approximately 1 micron. This restriction on the temperature is necessary for low-cost displays that use regular glass as the substrate. FIG. FIG. 4. This is a complete cross-section view of the diamond cathode used for display purposes. Selective diamond CVD deposition technology is another way to deposit thin diamond film 303. The thin molybdenum layer (100?) is applied to the pillar 300 after fabrication. The pillar 300’s top surface is covered with a thin layer of molybdenum (100?) using metal mask deposition technology. The diamond thin film 303 is then applied to the molybdenum surface using selective CVD.

The next step is to make the anode plate 500 (see FIG. 5) with Indium Tin Oxide (‘ITO”) as a layer. phosphors are applied using conventional thin film technologies like sputtering, evaporation, or thick film technology like screen printing. Glass is the substrate. The substrate is glass. A low-energy phosphor film, such as Zinc oxide (ZnO), is deposited on the glass and patterned with ITO coating. This disclosure does not need to detail the fabrication process.

“Referring to FIG. “Referring now to FIG. 5, an assembly process for a final device are shown. Between the cathode and anode layers 100, the cylinder-shaped spacers 501 are placed. The spacers 501 have a thickness of 12 m. This allows for a gap of 2 m between the anode and cathode. Spacers 501 must have a very high level of breakdown strength (minimum 100 MV/m at ambient temperature); a uniform thickness; low cost; and be (4) vacuum compatible. For the display, spacers 501 can be made from commercially available fibers. There are many types of insulation fibers on the market. The most popular are plastic and optical fibers. There are also fibers that are used in fiber composites. The fiber diameter is approximately 12 mm. The final device has a gap of 2 m. Spacers 501 can be used in any shape, not just a cylindrical one. A laminated layer made of mica can also be used to replace the fiber. Vacuum sealing is the final step in fabricating the diamond flat panel display. This is standard technology. Displays with a gap of 2 m between anode and cathode are designed to work at 50-60 volts.

The threshold energy of the phosphor material limits the operating voltage of the display described in this document. The threshold energy for the phosphor must be greater than the opening voltage. The threshold energy for ZnO (regular ZnO film) is 300 eV. Therefore, a display with this type of phosphor film requires at least 300 Volts of operating voltage. Basic parameters of the display include a 20 m gap, a 10 m pillar, and a 30 m spacer. Vacuum requirements are moderate, usually 10-3 torr. FIGS. FIGS. 29-32 are optical and scanning electron microscope images of the actual reduction that was done in practice. 5.”

“With reference FIG. “With reference to FIG. Each emitter for a pixel has an individual resistive layer. This means that if one emitter fails, all the other emitters will continue to emit electrons, regardless of whether it is short- or open.

Referring to FIG. “Referring to FIG. 7(a), a diode biased circuit 700 and 701 are designed to drive the display at 300 V using a low-voltage semiconductor driver. The anode 500 can be patterned with three sets of stripes and each set may be covered with a cathodoluminescent substance to provide a full-color display. FIG. 7 shows only one line of the anode, but this is for ease of explanation. 7(a). The pixels are addressed on the cathode plates by an addressing line that is orthogonal with the 500 anode plate. The anode 500 and cathode are addressed by 25 volt drivers 701 and 700, respectively. They both run on a DC power supply. The display’s threshold voltage is the output voltage of the DC power supply. A 250 volt DC power supply can be used for displays with a threshold voltage below 300 V. A color image can be displayed by sequentially addressing these electrodes. FIG. FIG. 7(b). This is a typical current voltage (I-V), curve for a diode. It also shows an operational load-line with an internal pillar resistance of 2.5 G. FIG. FIG. 7(c), shows the typical application of anode and/or cathode voltages, and the resulting anode/cathode potent.

There are many ways to make diamond films. Here are two methods. Laser ablation is the first method to deposit diamonds and carbon-like films. This involves a NdYAG laser bombarding a graphite target. This process has been detailed elsewhere. FIG. 20 through FIG. 20 through FIG. 25 show field emission data on a sample that was laser-ablated at room temperature. The data were taken using a tungsten carbide balls held at a distance of a few microns to the film. This allowed for the variation in the voltage between the ball and sample.

“FIGS. “FIGS.16-19” shows a schematic way to make a three-terminal device using diamond field emitters.

“Following is a variation on the basic scheme:

“1) Resistor trades each pixel.”

“2) Multiple emitters per pixel. This is very useful because it uses independent resistors.

“3) Multiple spacers. Two rows of fibers can be used: one that aligns with the x-axis and the other with the y axis. This will increase the structure’s breakdown voltage.

“4) Gray scale FPD methods. Two methods can be used to display a diode type diode. The first is where the driver modifies the voltage applied to diode in analog fashion. This causes the emission current to change, giving rise to various shades of grey. The second approach addresses each of the 16 (or similar) emitter pillars for each pixel individually. This allows you to vary the current reaching thephosphor.

“5) Although all structures in this document use diamond field emitters, you can also use any other low-electrons affinity material. These materials include borides, oxides, and cermet.

“6) Conditioning. At the beginning of field emission, all diamond samples must be conditioned. The emitter surface is conditioned by applying a higher voltage. The threshold voltage for an emitter drops dramatically after initial conditioning. At that voltage, the emitter can operate normally. Other methods of conditioning may include photo-conditioning or thermal activation. It is possible that periodic conditioning is required for the displays. This can be programmed so that the entire display is conditioned when the display is turned on.

There are many other uses for diamond cathode emitters, such as diamond cathodes to a vacuum valve. We will describe the structure of submicron and micron vacuum microelectronics using a diamond thin-film cathode.

There are many uses for vacuum microelectronics. However, they all depend on the unique properties of field emitting device. There are still vacuum valves and much effort has been put into finding a cold electron source that can replace the thermionic cathode of devices such as traveling wave tubes, cathode-ray tubes, and other microwave power amplifiers. The search for a cold electron source has been intense. It is important to have a faster start-up, a higher current density, and lower heater power. Field emission cathodes promise improvements in all three areas, which will result in greater operating power and efficiency. The high power pulse amplifier that is used to transmit air traffic control information has a 6mm diameter thermionic catode. It can produce a beam diameter 3mm and a maximum current density 4 A/cm2. A field emission diode would be required to achieve an equivalent current. Its diameter is less than 0.05mm. However, it is obvious that this diode would not be used in a traveling wave tube to prevent the emission of energetic ions. Concerns have been raised about the safety of solid state electronics in space and above defense systems that are exposed to electromagnetic radiation. Low voltage transport of low-density electron gas is the basis of most semiconductor devices. They are exposed to ionizing radiation and bombarded with both neutral and charged particles. This causes excitation of carriers, changing their density, and trapping charge at the interfaces to cause significant shifts in the bias voltage. This can cause temporary upset or even permanent damage, if the shifted characteristic causes runaway currents. The vacuum device itself is the most sensitive insulator. It will not be permanently damaged or overloaded by radiation.

“In addition, the travel time of an electron from the source to the drain will affect the speed of a semiconductor device. The transit time of an electron is affected by impurity or phono collisions in the lattice. These causes electron velocity saturation at approximately the speed of sound. Vacuum valves work by electrons moving from anode to cathode in a vacuum. Their passage is unaffected by molecular collisions. Transit times of less than one picosecond are possible for voltages typical (100 V) as well as dimensions (1?m).

“There is therefore a need to create a structure for related field emission devices that can be used for different purposes and a process of making them.

“Vacuum diodes can be manufactured using semiconductor-style fabrication technology. This allows for micron and submicron control of dimensionality.”

“Similar To FIG. 1, FIG. 8, FIG. A blank layer 800, which can be 500 A thick Al, is deposited using conventional deposition techniques such as evaporation and sputtering on a silicon Wafer 801. FIG. FIG. 9 shows how a layer 802 is applied to photo resist. This layer is spun on to a thickness between 1?m and 2?m. A chromium layer can be delineated using mask exposure to resist layer. The mask to etch to the Al layer 800 is the last resist layer. Al layer 800 serves two functions: addressing lines and the base of the field emitter. The different applications determine the dimensions of the base and the addressing lines. Submicron vacuum value applications have a pillar that is approximately 1 m to 2m in size and a line of about 0.1m. The resist remaining on the addressing line can be removed using a second mask or etching process.

“FIG. “FIG. 10″ is a cross-sectional view of the next stage in the fabrication submicron vacuum valves. Thermal Chemical Vapor Deposition (‘CVD”) is used to deposit a SiO2 layer 1000 with a thickness of 1?m on the substrate. In FIG. FIG. 11 shows how the resist 802 is removed from the pillar by an etching process. FIG. FIG. 11. Cross sectional view of second stage structure.

“The resistive layer is placed between the cathode (diamond thin layer) and the base (Al layer) for the same reasons as before. This disclosure uses diamond as both the cathode and resistive material. The high breakdown field and excellent insulation of diamond is due to the large energy gap (5.45 eV at room temperature). This allows for the fabrication of diamond thin films with a wide range resistivity. The film’s resistivity will decrease the closer it is to the conductance or valence bands. Partially successful attempts to dope diamonds using PH3 admixture were made. We were able to obtain activation energies between 0.84 and 1.15 eV. Hall effect measurements show that samples phosphorus-doped have n type conductivity. Although the resistivity of phosphorous-doped films is too high to be used in electronic applications, it can still be used as a resistive layer in vacuum microelectronics. Na (Sodium) is a potential donor in the shallow end and occupies the tetrahedrally-interstitial spot. The sodium formation energy is approximately 16.6 eV compared to the experimental cohesive energies for bulk Na. Because sodium is very solubilized in diamond, doping is done by ion implantation and other ion beam technologies.

Referring to FIG. 12 phosphorus-doped diamond thin film 1200 is selectively deposition by plasma CVD technology onto the base layer 800. The diamond deposition system has an additional gas inlet to allow for doping gas, and an ion beam to enable sodium doping. The ion beam for sodium doping is on standby, while the gas inlet to PH3 is opened. The flow rate of PH3 controls the donor concentration in diamond. The parameters of the device allow for a range of phosphorus concentrations in diamond, from 0.01 to 1 wt%. Thickness of the phosphorus-doped thin film 1200 is 0.55 m. The thickness of the phosphorus-doped diamond thick film 1200 is 0.5?m. The thickness of heavy-doped heavy-diamond thin movie 1201 with a sodium donor measures to about 100. The difference in thickness between SiO2 1000 thickness and diamond thin film 1201 thickness is approximately 0.5?m.

“Referring to FIG. 13. The silicon wafer 1300 is made with metallization layer 1301, and the two substrates, anode as well as cathode, are joined together using standard semiconductor technology. The assembly is compressed to a specified pressure, such as 10-3 torr. It then gets sealed with a vacuum compatible adhesive. The operating voltage and the geometry of the device determine the pressure within the devices. Vacuum sealing can be avoided if the operating voltage is lower that 10 Volts. The pressure inside the device must be maintained at 10-3 Torr.

“Following” is a description of diamond coating for a microtip-type vacuum triode.

“FIG. 14 shows a multielectrode configuration that allows for triode operation. For many years, the details of the structure and fabrication process are well-known. The well-known method of fabricating microtips and coating them with diamond thin film 1400 of 100 is used in the invention. The thickness is achieved by selective CVD deposition. Because the threshold electric field of diamond is lower than any other refractory metal, the diamond coating reduces the operating voltage by reducing it from 135 volts down to 15 volts.

“FIG. 15 shows the structure and configuration of a sensor equipped with a diamond cathode. The fabrication process for vacuum diodes is very similar. Only the anode plates 1500 are different. Anode plate 1500 is made from a thin silicon membrane. Any applied pressure or force changes the distance between anode and cathode. This alters the current that can be measured.

Although direct competition is unlikely between silicon semiconductor electronics, and vacuum electronics based upon the field emission cathode, they are compatible. Electronic systems that incorporate both semiconductor and vacuum devices are possible, even on the same chip. This hybrid could take advantage of the speed of vacuum transport.

Solid state devices can be made from silicon or vacuum electronics that are based on nonsilicon cathode materials. Because two types of basic materials are used in the fabrication of hybrid chips, there are many different processes and costs involved. Diamond has a unique combination desirable properties that make it appealing for many electronics. The present invention allows for the fabrication of a chip that is both based on solid-state electronics and vacuum electronics made from diamond.

“Even though the advantages of the present invention have been explained in detail, it is important to understand that many modifications, substitutions, and alterations may be made without departing from its spirit and scope as described by the attached claims.”

Summary for “Flat panel display using diamond thin films

Field emitters can be used in a variety of applications, including flat panel displays and vacuum microelectronics. Flat panel flat panel displays that are field emission-based have many advantages over other flat panel displays. These include low power consumption and high intensity, as well as a low projected cost. The current field emitters that use micro-fabricated metal tips are difficult to fabricate and have low yields, which increases the display cost. It is therefore desirable to have a better field emitter material and device structure and a simpler fabrication process. These issues are addressed by this invention.

Understanding the related physics will help you to appreciate the invention. The energy of electrons in a semiconductor or metal surface is generally lower than that of electrons at rest in vacuum. To emit electrons from any material into vacuum, energy must be provided to the electrons within the material. The metal cannot emit electrons if it is not provided with more energy than the electrons at rest in vacuum. You can provide energy through heat or radiation with light. The metal emits electrons when it receives enough energy. There are many types of electron emission phenomena. Thermionic emissions is an electrically charged particle that is emitted from an incandescent substance (such as a vacuum robe, or incandescent lamp). Photoemission is the release of electrons from a substance by using energy provided by radiation, particularly light. Secondary emission is caused by bombardment of a substance using charged particles, such as electrons and ions. The emission of electrons from one solid to the other is called electron injection. Field emission is the emission of electrons by an electric field.

For a metal of the phi value of 4.5 eV, a field of electric potentials of at least 109 V/m is required to produce measurable emission currents. To observe unambiguous field emission, high electric fields are required to be enhanced geometrically at the tip of an emission. This is in order to avoid any dielectric breakdown in electrode support materials. The emission characteristics of a field emitter are affected by its shape. Sharply pointed tips or needles are the best way to obtain field emission. A typical structure for a lithographically-defined sharp tip for a Cold Cathode is composed of small emitter structures of approximately 1-2 m in height and submicron (50nm) emitting points. The silicon dioxide layer separates them from the 0.5-m thick metal grid. Stanford Research Institute (‘SRI”) has shown that vacuum electronics can produce 100?A/tip with a cathode bias of 100-200V. To produce such fine tips, however it is necessary to have extensive fabrication facilities in order to precisely tailor the emitter into a conical form. Because the cone size of the lithographic equipment is restricted, it makes it difficult to create large-area field emitters. Fine feature lithography is difficult on large substrates, as required for flat panel display types applications.

“According to the invention, a flat panel LCD is provided that incorporates diamond film to increase image intensity at low costs.”

“The present invention provides for a flat panel LCD with a diamond field emission catalyst to attain the above advantages.”

“Vacuum diodes can be fabricated on a substrate using standard fabrication techniques such as deposition, masking, and etching.”

Referring to FIG. 1. The drawings show a starting step, a blanket 100 of 5000. Thick chromium, which can also be aluminum (Al), molybdenum [Mo], or titanium (Ti), is deposited using conventional deposition techniques such as evaporation or sputtering. Next, a layer is applied of photo resist by spinning to a thickness between 1 and 2 m. The chromium layer 100 can be delineated using mask exposure. The 100th resist layer is used as a mask for the 100 chromium layers 100. The chromium 100 layer serves two purposes: it forms the addressing lines for field emitters and the base. Different applications determine the dimensions of the base and the addressing lines. Display applications have a pillar size of approximately 100 m to 250m, and a line of about 25m. Vacuum microelectronic devices, such as high-power, high frequency amplifiers, have a feature size of several microns. Final, any residual resist is removed after etching (see FIG. 2).”

“FIG. “FIG. The metal mask deposition technique is used to deposit the conductive pillars 300 onto the bases. The pillars 300 are slightly smaller than the bases. If the base measures 120 m in width, then the optimal size for the pillars 300 is 100 m. This reduces the need to align the metal mask 304 to substrate. It also results in a lower manufacturing cost. Device parameters like operating voltage, spacer size and gap between anode and cathode determine the height of the 300 pillars. Here, pillars of 10 m height are used. The FN theory of field emissions states that the emission current is sensitive to the distance between the anode cathode, cathode, and the surface conditions of cathode. The thickness of thin film cathodes can be controlled using conventional technologies like sputtering and evaporation. However, uniformity of the emission current across large areas is still a problem. If the material has a 4.5 eV working function and the applied electric field is 100 MV/m, then a 1% difference between the anode and cathode will result in 10% variation in the emission current. The 300 pillars are made of resistive material to increase the uniformity in the emission. A resistive material adjusts the potential between the anode and cathode. The potential across the gap between cathode and anode is smaller the higher the pillar. If the pillars are made of a suitable resistor material, the emission current can be reduced or eliminated by reducing the difference in pillar height. The resistive pillars 300 also serve as a current control layer. Because of surface conditions such as contamination, roughness and flatness, some emitters have a higher emission current than others. The resistive pillar 300 is present so that the potential drop across pillars with higher emission currents is greater than the drop across pillars with lower emission currents. The optimal thickness of the resistive 101 layer in the 10 m high pillars 300 are 5 m.

Referring to FIG. “Referring still to FIG. Layer 302’s function is to dissipate heat from the emission current.

“In FIG. 3. The diamond thin film 303 was deposited using room temperature deposition technology, such as laser ablation through holes in the metal mask. 304. The thickness of diamond 303 is approximately 1 micron. This restriction on the temperature is necessary for low-cost displays that use regular glass as the substrate. FIG. FIG. 4. This is a complete cross-section view of the diamond cathode used for display purposes. Selective diamond CVD deposition technology is another way to deposit thin diamond film 303. The thin molybdenum layer (100?) is applied to the pillar 300 after fabrication. The pillar 300’s top surface is covered with a thin layer of molybdenum (100?) using metal mask deposition technology. The diamond thin film 303 is then applied to the molybdenum surface using selective CVD.

The next step is to make the anode plate 500 (see FIG. 5) with Indium Tin Oxide (‘ITO”) as a layer. phosphors are applied using conventional thin film technologies like sputtering, evaporation, or thick film technology like screen printing. Glass is the substrate. The substrate is glass. A low-energy phosphor film, such as Zinc oxide (ZnO), is deposited on the glass and patterned with ITO coating. This disclosure does not need to detail the fabrication process.

“Referring to FIG. “Referring now to FIG. 5, an assembly process for a final device are shown. Between the cathode and anode layers 100, the cylinder-shaped spacers 501 are placed. The spacers 501 have a thickness of 12 m. This allows for a gap of 2 m between the anode and cathode. Spacers 501 must have a very high level of breakdown strength (minimum 100 MV/m at ambient temperature); a uniform thickness; low cost; and be (4) vacuum compatible. For the display, spacers 501 can be made from commercially available fibers. There are many types of insulation fibers on the market. The most popular are plastic and optical fibers. There are also fibers that are used in fiber composites. The fiber diameter is approximately 12 mm. The final device has a gap of 2 m. Spacers 501 can be used in any shape, not just a cylindrical one. A laminated layer made of mica can also be used to replace the fiber. Vacuum sealing is the final step in fabricating the diamond flat panel display. This is standard technology. Displays with a gap of 2 m between anode and cathode are designed to work at 50-60 volts.

The threshold energy of the phosphor material limits the operating voltage of the display described in this document. The threshold energy for the phosphor must be greater than the opening voltage. The threshold energy for ZnO (regular ZnO film) is 300 eV. Therefore, a display with this type of phosphor film requires at least 300 Volts of operating voltage. Basic parameters of the display include a 20 m gap, a 10 m pillar, and a 30 m spacer. Vacuum requirements are moderate, usually 10-3 torr. FIGS. FIGS. 29-32 are optical and scanning electron microscope images of the actual reduction that was done in practice. 5.”

“With reference FIG. “With reference to FIG. Each emitter for a pixel has an individual resistive layer. This means that if one emitter fails, all the other emitters will continue to emit electrons, regardless of whether it is short- or open.

Referring to FIG. “Referring to FIG. 7(a), a diode biased circuit 700 and 701 are designed to drive the display at 300 V using a low-voltage semiconductor driver. The anode 500 can be patterned with three sets of stripes and each set may be covered with a cathodoluminescent substance to provide a full-color display. FIG. 7 shows only one line of the anode, but this is for ease of explanation. 7(a). The pixels are addressed on the cathode plates by an addressing line that is orthogonal with the 500 anode plate. The anode 500 and cathode are addressed by 25 volt drivers 701 and 700, respectively. They both run on a DC power supply. The display’s threshold voltage is the output voltage of the DC power supply. A 250 volt DC power supply can be used for displays with a threshold voltage below 300 V. A color image can be displayed by sequentially addressing these electrodes. FIG. FIG. 7(b). This is a typical current voltage (I-V), curve for a diode. It also shows an operational load-line with an internal pillar resistance of 2.5 G. FIG. FIG. 7(c), shows the typical application of anode and/or cathode voltages, and the resulting anode/cathode potent.

There are many ways to make diamond films. Here are two methods. Laser ablation is the first method to deposit diamonds and carbon-like films. This involves a NdYAG laser bombarding a graphite target. This process has been detailed elsewhere. FIG. 20 through FIG. 20 through FIG. 25 show field emission data on a sample that was laser-ablated at room temperature. The data were taken using a tungsten carbide balls held at a distance of a few microns to the film. This allowed for the variation in the voltage between the ball and sample.

“FIGS. “FIGS.16-19” shows a schematic way to make a three-terminal device using diamond field emitters.

“Following is a variation on the basic scheme:

“1) Resistor trades each pixel.”

“2) Multiple emitters per pixel. This is very useful because it uses independent resistors.

“3) Multiple spacers. Two rows of fibers can be used: one that aligns with the x-axis and the other with the y axis. This will increase the structure’s breakdown voltage.

“4) Gray scale FPD methods. Two methods can be used to display a diode type diode. The first is where the driver modifies the voltage applied to diode in analog fashion. This causes the emission current to change, giving rise to various shades of grey. The second approach addresses each of the 16 (or similar) emitter pillars for each pixel individually. This allows you to vary the current reaching thephosphor.

“5) Although all structures in this document use diamond field emitters, you can also use any other low-electrons affinity material. These materials include borides, oxides, and cermet.

“6) Conditioning. At the beginning of field emission, all diamond samples must be conditioned. The emitter surface is conditioned by applying a higher voltage. The threshold voltage for an emitter drops dramatically after initial conditioning. At that voltage, the emitter can operate normally. Other methods of conditioning may include photo-conditioning or thermal activation. It is possible that periodic conditioning is required for the displays. This can be programmed so that the entire display is conditioned when the display is turned on.

There are many other uses for diamond cathode emitters, such as diamond cathodes to a vacuum valve. We will describe the structure of submicron and micron vacuum microelectronics using a diamond thin-film cathode.

There are many uses for vacuum microelectronics. However, they all depend on the unique properties of field emitting device. There are still vacuum valves and much effort has been put into finding a cold electron source that can replace the thermionic cathode of devices such as traveling wave tubes, cathode-ray tubes, and other microwave power amplifiers. The search for a cold electron source has been intense. It is important to have a faster start-up, a higher current density, and lower heater power. Field emission cathodes promise improvements in all three areas, which will result in greater operating power and efficiency. The high power pulse amplifier that is used to transmit air traffic control information has a 6mm diameter thermionic catode. It can produce a beam diameter 3mm and a maximum current density 4 A/cm2. A field emission diode would be required to achieve an equivalent current. Its diameter is less than 0.05mm. However, it is obvious that this diode would not be used in a traveling wave tube to prevent the emission of energetic ions. Concerns have been raised about the safety of solid state electronics in space and above defense systems that are exposed to electromagnetic radiation. Low voltage transport of low-density electron gas is the basis of most semiconductor devices. They are exposed to ionizing radiation and bombarded with both neutral and charged particles. This causes excitation of carriers, changing their density, and trapping charge at the interfaces to cause significant shifts in the bias voltage. This can cause temporary upset or even permanent damage, if the shifted characteristic causes runaway currents. The vacuum device itself is the most sensitive insulator. It will not be permanently damaged or overloaded by radiation.

“In addition, the travel time of an electron from the source to the drain will affect the speed of a semiconductor device. The transit time of an electron is affected by impurity or phono collisions in the lattice. These causes electron velocity saturation at approximately the speed of sound. Vacuum valves work by electrons moving from anode to cathode in a vacuum. Their passage is unaffected by molecular collisions. Transit times of less than one picosecond are possible for voltages typical (100 V) as well as dimensions (1?m).

“There is therefore a need to create a structure for related field emission devices that can be used for different purposes and a process of making them.

“Vacuum diodes can be manufactured using semiconductor-style fabrication technology. This allows for micron and submicron control of dimensionality.”

“Similar To FIG. 1, FIG. 8, FIG. A blank layer 800, which can be 500 A thick Al, is deposited using conventional deposition techniques such as evaporation and sputtering on a silicon Wafer 801. FIG. FIG. 9 shows how a layer 802 is applied to photo resist. This layer is spun on to a thickness between 1?m and 2?m. A chromium layer can be delineated using mask exposure to resist layer. The mask to etch to the Al layer 800 is the last resist layer. Al layer 800 serves two functions: addressing lines and the base of the field emitter. The different applications determine the dimensions of the base and the addressing lines. Submicron vacuum value applications have a pillar that is approximately 1 m to 2m in size and a line of about 0.1m. The resist remaining on the addressing line can be removed using a second mask or etching process.

“FIG. “FIG. 10″ is a cross-sectional view of the next stage in the fabrication submicron vacuum valves. Thermal Chemical Vapor Deposition (‘CVD”) is used to deposit a SiO2 layer 1000 with a thickness of 1?m on the substrate. In FIG. FIG. 11 shows how the resist 802 is removed from the pillar by an etching process. FIG. FIG. 11. Cross sectional view of second stage structure.

“The resistive layer is placed between the cathode (diamond thin layer) and the base (Al layer) for the same reasons as before. This disclosure uses diamond as both the cathode and resistive material. The high breakdown field and excellent insulation of diamond is due to the large energy gap (5.45 eV at room temperature). This allows for the fabrication of diamond thin films with a wide range resistivity. The film’s resistivity will decrease the closer it is to the conductance or valence bands. Partially successful attempts to dope diamonds using PH3 admixture were made. We were able to obtain activation energies between 0.84 and 1.15 eV. Hall effect measurements show that samples phosphorus-doped have n type conductivity. Although the resistivity of phosphorous-doped films is too high to be used in electronic applications, it can still be used as a resistive layer in vacuum microelectronics. Na (Sodium) is a potential donor in the shallow end and occupies the tetrahedrally-interstitial spot. The sodium formation energy is approximately 16.6 eV compared to the experimental cohesive energies for bulk Na. Because sodium is very solubilized in diamond, doping is done by ion implantation and other ion beam technologies.

Referring to FIG. 12 phosphorus-doped diamond thin film 1200 is selectively deposition by plasma CVD technology onto the base layer 800. The diamond deposition system has an additional gas inlet to allow for doping gas, and an ion beam to enable sodium doping. The ion beam for sodium doping is on standby, while the gas inlet to PH3 is opened. The flow rate of PH3 controls the donor concentration in diamond. The parameters of the device allow for a range of phosphorus concentrations in diamond, from 0.01 to 1 wt%. Thickness of the phosphorus-doped thin film 1200 is 0.55 m. The thickness of the phosphorus-doped diamond thick film 1200 is 0.5?m. The thickness of heavy-doped heavy-diamond thin movie 1201 with a sodium donor measures to about 100. The difference in thickness between SiO2 1000 thickness and diamond thin film 1201 thickness is approximately 0.5?m.

“Referring to FIG. 13. The silicon wafer 1300 is made with metallization layer 1301, and the two substrates, anode as well as cathode, are joined together using standard semiconductor technology. The assembly is compressed to a specified pressure, such as 10-3 torr. It then gets sealed with a vacuum compatible adhesive. The operating voltage and the geometry of the device determine the pressure within the devices. Vacuum sealing can be avoided if the operating voltage is lower that 10 Volts. The pressure inside the device must be maintained at 10-3 Torr.

“Following” is a description of diamond coating for a microtip-type vacuum triode.

“FIG. 14 shows a multielectrode configuration that allows for triode operation. For many years, the details of the structure and fabrication process are well-known. The well-known method of fabricating microtips and coating them with diamond thin film 1400 of 100 is used in the invention. The thickness is achieved by selective CVD deposition. Because the threshold electric field of diamond is lower than any other refractory metal, the diamond coating reduces the operating voltage by reducing it from 135 volts down to 15 volts.

“FIG. 15 shows the structure and configuration of a sensor equipped with a diamond cathode. The fabrication process for vacuum diodes is very similar. Only the anode plates 1500 are different. Anode plate 1500 is made from a thin silicon membrane. Any applied pressure or force changes the distance between anode and cathode. This alters the current that can be measured.

Although direct competition is unlikely between silicon semiconductor electronics, and vacuum electronics based upon the field emission cathode, they are compatible. Electronic systems that incorporate both semiconductor and vacuum devices are possible, even on the same chip. This hybrid could take advantage of the speed of vacuum transport.

Solid state devices can be made from silicon or vacuum electronics that are based on nonsilicon cathode materials. Because two types of basic materials are used in the fabrication of hybrid chips, there are many different processes and costs involved. Diamond has a unique combination desirable properties that make it appealing for many electronics. The present invention allows for the fabrication of a chip that is both based on solid-state electronics and vacuum electronics made from diamond.

“Even though the advantages of the present invention have been explained in detail, it is important to understand that many modifications, substitutions, and alterations may be made without departing from its spirit and scope as described by the attached claims.”

Click here to view the patent on Google Patents.

How to Search for Patents

A patent search is the first step to getting your patent. You can do a google patent search or do a USPTO search. Patent-pending is the term for the product that has been covered by the patent application. You can search the public pair to find the patent application. After the patent office approves your application, you will be able to do a patent number look to locate the patent issued. Your product is now patentable. You can also use the USPTO search engine. See below for details. You can get help from a patent lawyer. Patents in the United States are granted by the US trademark and patent office or the United States Patent and Trademark office. This office also reviews trademark applications.

Are you interested in similar patents? These are the steps to follow:

1. Brainstorm terms to describe your invention, based on its purpose, composition, or use.

Write down a brief, but precise description of the invention. Don’t use generic terms such as “device”, “process,” or “system”. Consider synonyms for the terms you chose initially. Next, take note of important technical terms as well as keywords.

Use the questions below to help you identify keywords or concepts.

  • What is the purpose of the invention Is it a utilitarian device or an ornamental design?
  • Is invention a way to create something or perform a function? Is it a product?
  • What is the composition and function of the invention? What is the physical composition of the invention?
  • What’s the purpose of the invention
  • What are the technical terms and keywords used to describe an invention’s nature? A technical dictionary can help you locate the right terms.

2. These terms will allow you to search for relevant Cooperative Patent Classifications at Classification Search Tool. If you are unable to find the right classification for your invention, scan through the classification’s class Schemas (class schedules) and try again. If you don’t get any results from the Classification Text Search, you might consider substituting your words to describe your invention with synonyms.

3. Check the CPC Classification Definition for confirmation of the CPC classification you found. If the selected classification title has a blue box with a “D” at its left, the hyperlink will take you to a CPC classification description. CPC classification definitions will help you determine the applicable classification’s scope so that you can choose the most relevant. These definitions may also include search tips or other suggestions that could be helpful for further research.

4. The Patents Full-Text Database and the Image Database allow you to retrieve patent documents that include the CPC classification. By focusing on the abstracts and representative drawings, you can narrow down your search for the most relevant patent publications.

5. This selection of patent publications is the best to look at for any similarities to your invention. Pay attention to the claims and specification. Refer to the applicant and patent examiner for additional patents.

6. You can retrieve published patent applications that match the CPC classification you chose in Step 3. You can also use the same search strategy that you used in Step 4 to narrow your search results to only the most relevant patent applications by reviewing the abstracts and representative drawings for each page. Next, examine all published patent applications carefully, paying special attention to the claims, and other drawings.

7. You can search for additional US patent publications by keyword searching in AppFT or PatFT databases, as well as classification searching of patents not from the United States per below. Also, you can use web search engines to search non-patent literature disclosures about inventions. Here are some examples:

  • Add keywords to your search. Keyword searches may turn up documents that are not well-categorized or have missed classifications during Step 2. For example, US patent examiners often supplement their classification searches with keyword searches. Think about the use of technical engineering terminology rather than everyday words.
  • Search for foreign patents using the CPC classification. Then, re-run the search using international patent office search engines such as Espacenet, the European Patent Office’s worldwide patent publication database of over 130 million patent publications. Other national databases include:
  • Search non-patent literature. Inventions can be made public in many non-patent publications. It is recommended that you search journals, books, websites, technical catalogs, conference proceedings, and other print and electronic publications.

To review your search, you can hire a registered patent attorney to assist. A preliminary search will help one better prepare to talk about their invention and other related inventions with a professional patent attorney. In addition, the attorney will not spend too much time or money on patenting basics.

Download patent guide file – Click here