CS196836B1 - COLD SEMICONDUCTOR READY CATALOG - Google Patents

Abstract

The present invention relates to a cold semiconductor tip cathode arranged on a single-crystalline semiconductor material provided with an oxide layer with at least one hole

Description

The present invention relates to a cold semiconductor tip cathode disposed on a monocrystalline semiconductor material provided with an oxide layer with at least one opening.

A cold metal cathode (dielectric) metal tip metal cathode, wherein each metal tip of the multi-point system is formed on a metal continuous bottom layer within an aperture formed by etching a dielectric underneath the top metal layer aperture is known, for example, from U.S. Pat. 3 789 471, 3 812 559 and from CA SPINDT:

A Thin-Film Field-Emission Cathode; Communications, 3504 - 3505. The thickness of the dielectric is about 1 µm, the height of the tips is less than the thickness of the dielectric. The disadvantage is a very complicated manufacturing process in which each opening of the upper metal layer is first coated with an extruded layer. a further additional sealing layer, both of which are extended and additional, must be removed.

Furthermore, it is from Article I. BRODIE: Bombardment of field-emission cathodes by positive ions formed in the interelectrode region; lnt. J. Electronic, 1975, Vol. 38, no. 4, 541-550, a known student-tip cathode of a metal-tipped semiconductor (dielectric) metal structure, wherein each metal tip of a multi-tip system is formed, for example, on silicon within an orifice formed by etching a layer of silica below the orifice of molybdenum. A disadvantage of this arrangement, where the thickness of the dielectric is about 1 µm and higher196836

The 2 ka spikes are smaller than the dielectric thickness, are complex to the prior art, wherein each orifice of the molybdenum layer is also gradually closed when the pyramid conical molybdenum tip is vaporized by an additional sealing layer which is removed after formation of the molybdenum tip. .

Further, from R.N. THOMAS, R.A. WICKSTROM, D.K. SCHRODER and H.G. NATHANSON: Fabrication and some applications of large-area Silicon field emission arrays; Solid State Electronics, 1974, Vol. 17, s. 155-163, a cold tip semiconductor cathode arrangement is known in which the individual emitters are formed by silicon spikes of approximately 10 µm and spaced at 25 µm, the radius of curvature being, for example, about 20 nm. This known arrangement is made by, for example, providing a surface (111) of the single crystal Si by means of thermal oxidation and photolithography with a system of separated squares of a SiOg layer with a pitch of e.g. 25 µm and a thickness of eg 1 µm. By selective etching of the nitric, acetic and hydrofluoric acid mixtures, the silicon is etched and then SiO2 is removed with hydrofluoric acid. The spikes are pointed by any further etching of silicon. The cathodes are formed from silicon type N, photocathodes on silicon type P. The distance of the anode from the cathode is 300-500 µm and a vacuum is applied e.g. at a pressure of 130 pPa to 1.3 / µPa. The disadvantage of this arrangement and the semiconductor tips produced by the elective etching of monocrystalline silicon using a photolithography mask are technological difficulties, for example, a resist mask formed from mutually separated islets is susceptible to leaching off individual SiOg islands by local etching of the silica layer islets of resist, and thus to produce less efficient or defective cathodes. Also, the eventual final etching of the tip tips is labor intensive and increases production costs.

Said disadvantages of the complexity of the manufacturing technology required to make the prior art arrangements are largely eliminated by the cold semiconductor tip cathode arranged in accordance with the invention. SUMMARY OF THE INVENTION In the oxide layer opening on the semiconductor material, the tip of the semiconductor material consists of a spike consisting of a base that at least partially fills the opening in the oxide layer and a tapered portion.

The advantage of the cold semiconductor tip cathode according to the invention is that it is simpler, yet easier and cheaper to manufacture than the prior art cold tip cathodes. The cold semiconductor tip cathode arrangement of the present invention can be readily fabricated by using a simple masking technology that first creates the orifice (s) in the oxide layer, and then using epitaxy technology that creates a semiconductor tip at each of said apertures.

The attached drawing shows schematically embodiments of a single tip of a cold semiconductor cathode arranged according to the invention.

- 3 196836

In the drawing, FIG. 1 is an individual tip of a cold semiconductor cathode whose base partially fills an opening in the oxide layer, FIG. 2 is an individual tip of a cold semiconductor cathode whose base fills an opening in the oxide layer; wherein the base fills an opening in the oxide layer, wherein the base area of the tapered portion is larger than the aperture area in the oxide layer.

The single tip 14 of the cold semiconductor cathode shown in FIG. 1 is formed on a monocrystalline semiconductor material 11, for example of the N type, with orientation (111) in the opening 13 of the oxide layer 12 (e.g. 5 µm diameter). The tip 14 formed of semiconductor material consists of a base 141 and a tapered portion 142. The base 141 of the tip 14 fills a portion of the height of the opening 13.

There is an anode opposite the tip 14 at a distance of e.g. 500 pm, which is not plotted.

An epitaxial technology formed by a tip 14 of a semiconductor material such as N-type has the same crystal orientation as the single crystal of the base material 11, i.e. orientation (111), which results in a tapering epitaxial growth above its base 141. the tip portion 14 representing the tip 14.

FIG. 2 shows an arrangement similar to that of FIG. 1, where the base 141 of the semiconductor tip 14 completely fills the opening 13 in the oxide layer 12 so that the entire tapered portion 142 is formed above the oxide layer 12.

FIG. 3 shows an arrangement similar to that of FIG. 1, where the base 141 of the semiconductor tip 14 completely fills the opening 13 in the oxide layer 12, wherein the base area of the tapered portion 142 is larger than the opening 13 in the oxide layer 12.

Also, the arrangement of Fig. 2 and Fig. 3 can be made by epitaxy similar to that of Fig. 1.

The function of the cathode arranged according to the invention is similar to that of prior art cathodes emitting in a strong electric field, utilizing the physical principle of emission, where solid electrons are released by the surface barrier being narrowed by the external electric field to such an extent barrier through tunnel effect.

For a higher current density, the entire spike system is used, all spikes of the system being produced at one time by epitaxy using an oxide layer aperture system.

Claims (1)

A cold semiconductor tip cathode disposed on a monocrystalline semiconductor material provided with an oxide layer with at least one aperture, characterized in that on the semiconductor material> (11) in the aperture (13) of the oxide layer (12) is formed a semiconductor material tip (14) consisting of a base (141) that at least partially fills the opening (13) in the oxide layer (12), and from the tapered part (142);