Directly flat-attached switching component for active frequency selective surface and fabricating method thereof

Abstract

The present invention provides a switching component of a directly flat-attached active frequency selective surface (AFSS) and fabricating method thereof. The present invention utilizes P-type and N-type thin film materials to fabricate a PN diode switching component capable of adjusting a resonance frequency of the AFSS, such that the AFSS together with the switching component could be integrally fabricated into a single thin film. Therefore, by utilizing a stepwise coating method to fabricate each layer with corresponding material, an equivalent length of a metal pattern could be adjusted, thereby changing the resonance frequency of the AFSS.

Claims

1. A fabricating method for a switching component of a directly flat-attached active frequency selective surface (AFSS), the fabricating method comprising: (A) providing a dielectric substrate, and preparing a metal wire on the dielectric substrate; (B) fabricating an opening in the metal wire to expose the dielectric substrate; (C) preparing a high work function metal layer from a periphery of an end of the opening to a bottom of the end of the opening, wherein the dielectric substrate remains exposed at a bottom of another end of the opening; (D) preparing a P-type material layer on an upper surface of the high work function metal layer and a side of the high work function metal layer facing the another end of the opening, wherein the dielectric substrate still remains exposed at the bottom of the another end of the opening; (E) preparing an N-type material layer on an upper surface of the P-type material layer and a side of the P-type material layer facing the another end of the opening, wherein the dielectric substrate still remains exposed at the bottom of the another end of the opening; and (F) preparing a low work function metal layer from an upper surface of the N-type material layer to a periphery of the another end of the opening, wherein the low work function metal layer across the another end of the opening is mutually in contact with the N-type material layer, the dielectric substrate exposed at the bottom of the another end of the opening and the metal wire to form a PN diode switching component of the AFSS.

2. The fabricating method of claim 1, wherein the dielectric substrate is made of an electrically insulating material or a semiconductor material.

3. The fabricating method of claim 1, wherein the dielectric substrate is a silicon substrate or an FR4 glass fiber epoxy substrate.

4. The fabricating method of claim 1, wherein the metal wire is a copper wire, an aluminum wire or a silver wire.

5. The fabricating method of claim 1, wherein the high work function metal layer is made of platinum (Pt), nickel (Ni), gold (Au), cobalt (Co) or Iridium (Ir).

6. The fabricating method of claim 1, wherein the P-type material layer is made of NiOx, SnOx, CuCrCaOx or CuAlO.sub.2.

7. The fabricating method of claim 1, wherein the N-type material layer is made of doped ZnO or undoped ZnO.

8. The fabricating method of claim 1, wherein the low work function metal layer is made of titanium (Ti), aluminum (Al), zinc (Zn), tin (Sn), manganese (Mn), iron (Fe), ruthenium (Ru), indium (In), copper (Cu), chromium (Cr), silver (Ag) or lead (Pb).

9. The fabricating method of claim 1, wherein a thickness of the high work function metal layer is 50 nm-100 nm, a thickness of the low work function metal layer 100 nm-200 nm, and a thickness of the P-type material layer or the N-type material layer is 50 nm-100 nm.

10. A switching component for a directly flat-attached active frequency selective surface (AFSS), wherein a fabricating method for the switching component comprising: (A) providing a dielectric substrate, and preparing a metal wire on the dielectric substrate; (B) fabricating an opening in the metal wire to expose the dielectric substrate; (C) preparing a high work function metal layer from a periphery of an end of the opening to a bottom of the end of the opening, wherein the dielectric substrate remains exposed at a bottom of another end of the opening; (D) preparing a P-type material layer on an upper surface of the high work function metal layer and a side of the high work function metal layer facing the another end of the opening, wherein the dielectric substrate still remains exposed at the bottom of the another end of the opening; (E) preparing an N-type material layer on an upper surface of the P-type material layer and a side of the P-type material layer facing the another end of the opening, wherein the dielectric substrate still remains exposed at the bottom of the another end of the opening; and (F) preparing a low work function metal layer from an upper surface of the N-type material layer to a periphery of the another end of the opening, wherein the low work function metal layer across the another end of the opening is mutually in contact with the N-type material layer, the dielectric substrate exposed at the bottom of the another end of the opening and the metal wire to form a PN diode switching component of the AFSS.

11. The switching component of claim 10, wherein the dielectric substrate is made of an electrically insulating material or a semiconductor material.

12. The switching component of claim 10, wherein the dielectric substrate is a silicon substrate or an FR4 glass fiber epoxy substrate.

13. The switching component of claim 10, wherein the metal wire is a copper wire, an aluminum wire or a silver wire.

14. The switching component of claim 10, wherein the high work function metal layer is made of platinum (Pt), nickel (Ni),gold (Au), cobalt (Co) or Iridium (Ir).

15. The switching component of claim 10, wherein the P-type material layer is made of NiOx, SnOx, CuCrCaOx or CuAlO.sub.2.

16. The switching component of claim 10, wherein the N-type material layer is made of doped ZnO or undoped ZnO.

17. The switching component of claim 10, wherein the low work function metal layer is made of titanium (Ti), aluminum (Al), zinc (Zn), tin (Sn), manganese (Mn), iron (Fe), ruthenium (Ru), indium (In), copper (Cu), chromium (Cr), silver (Ag) or lead (Pb).

18. The switching component of claim 10, wherein a thickness of the high work function metal layer is 50 nm-100 nm, a thickness of the low work function metal layer 100 nm-200 nm, and a thickness of the P-type material layer or the N-type material layer is 50 nm-100 nm.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is an actual photograph of a high-frequency switching component connected to an active frequency selective surface (AFSS) circuit.

(2) FIG. 2 is an actual photograph of a PN diode switching component connected with an AFSS circuit according to the embodiment of the present invention.

(3) FIG. 3 is a flow chart of a fabricating process for a switching component of a directly flat-attached AFSS according to an embodiment of the present invention.

(4) FIG. 4 is a schematic diagram of a fabricating process for a switching component of a directly flat-attached AFSS according to an embodiment of the present invention.

(5) FIG. 5 is a measured result of a PN diode switching component when high frequency signals are inputted according to an embodiment of the present invention.

DETAILED DESCRIPTION

(6) The embodiments of the present invention are described by way of specific examples, and those skilled in the art can readily understand the advantages and functions of the present invention from following description.

(7) Please refer to FIG. 3, which is a flow chart of a fabricating process for a switching component of a directly flat-attached active frequency selective surface (AFSS) according to an embodiment of the present invention. As shown in FIG. 3, the fabricating process for the switching component of the directly flat-attached AFSS of the present invention comprises steps of:

(8) Step S101: (A) Provide a dielectric substrate, and prepare a metal wire on the dielectric substrate.

(9) Step S102: (B) Fabricate an opening in the metal wire to expose the dielectric substrate.

(10) Step S103: (C) Prepare a high work function metal layer from a periphery of an end of the opening to a bottom of the end of the opening, wherein the dielectric substrate remains exposed at a bottom of another end of the opening.

(11) Step S104: (D) Prepare a P-type material layer on an upper surface of the high work function metal layer and a side of the high work function metal layer facing the another end of the opening, wherein the dielectric substrate still remains exposed at the bottom of the another end of the opening.

(12) Step S105: (E) Prepare an N-type material layer on an upper surface of the P-type material layer and a side of the P-type material layer facing the another end of the opening, wherein the dielectric substrate still remains exposed at the bottom of the another end of the opening.

(13) Step S106: (F) Prepare a low work function metal layer from an upper surface of the N-type material layer to a periphery of the another end of the opening, wherein the low work function metal layer across to the another end of the opening is mutually in contact with the N-type material layer, the dielectric substrate exposed at the bottom of the another end of the opening and the metal wire, to form a PN diode switching component of the AFSS.

(14) The present invention further provides a switching component for a directly flat-attached AFSS, and the switching component is prepared by the above fabricating method. Please refer to FIG. 4, which is a schematic diagram of a fabricating process for a switching component of a directly flat-attached AFSS according to an embodiment of the present invention. As shown in FIG. 4, a switching component of a directly flat-attached AFSS of the present invention comprises a dielectric substrate 1, a metal wire 2, an opening 3 of the metal wire 2, a high work function metal layer 4, a P-type material layer 5, an N-Type material layer 6, a low work function metal layer 7. The opening 3 is left in the middle of the metal wire 2 to install the switching component. The high work function metal layer 4 forms an ohmic contact with the P-type material layer 5, and the low work function metal layer 7 forms an ohmic contact with the N-type material layer 6.

EMBODIMENT

(15) In this embodiment, first, a dielectric substrate is provided, and a copper wire is disposed on the dielectric substrate and an opening is reserved. Second, a high work function metal layer (i.e. a Pt layer) is sputtered from a periphery of one end of the opening to a bottom of the one end of the opening, and a thickness of the Pt layer is 70 nm, wherein the dielectric substrate remains exposed at a bottom of another end of the opening. Third, a P-type material layer (i.e. an NiO layer) with a thickness of 100 nm is sputtered on an upper surface of the Pt layer and a side of the Pt layer facing the another end of the opening (sputtering conditions: 100 W, O.sub.2: 10 SCCM, working pressure: 3 mtorr), wherein the dielectric substrate still remains exposed at the bottom of the another end of the opening. Four, an N-type material layer (i.e. a ZnO layer) with a thickness of 100 nm is sputtered on an upper surface of the NiO layer and a side of the NiO layer facing the another end of the opening (sputtering conditions: 100 W, Ar: 7 SCCM, O.sub.2: 3 SCCM, working pressure: 5 mtorr), wherein the dielectric substrate still remains exposed at the bottom of the another end of the opening; Five, a low work function metal layer (i.e. an Al layer) with a thickness of 200 nm is disposed from an upper surface of the ZnO layer to a periphery of the another end of the opening such that the low work function metal layer across to the another end of the opening is mutually in contact with the N-type material layer, the dielectric substrate exposed at the bottom of the another end of the opening and the metal wire, to form a PN diode switching component of the AFSS.

(16) Please refer to FIG. 5, which is a measured result of a PN diode switching component when high frequency signals are inputted according to an embodiment of the present invention. Two terminal of the PN diode switching component are connected to a network analyzer, and responses of the high-frequency signals transmitted in the PN diode switching component are measured. As shown in FIG. 5, it could be clearly seen that when the diode is not turned on, i.e. when a bias voltage is 0V, the PN diode switching component is close to an open state, such that a transmission signal strength loss S.sub.21 is close to an original condition in which the PN diode switching component is completely open (i.e. the diode is unattached, and there is a gap between two segments of circuits, which are not conducted at all). If the diode is turned on, i.e. when the bias voltage is 10V, the PN diode switching component is close to a short-circuit state, such that the transmission signal strength loss S21 is less and close to a state of 0 db in which the PN diode switching component is fully turned on. Therefore, as shown in FIG. 5, it is assured that the embodiment of the present invention has disposed a thin film diode component which could actively adjust a frequency selective surface without additional soldered switching components. The PN diode is turned on by an external bias to conduct a path, and an open circuit is formed when there is no external bias. By utilizing the switching component, an equivalent length of a metal pattern is adjusted, thereby changing a resonance frequency of an active frequency selective surface, to achieve the purpose of allowing an electromagnetic wave with a specific wavelength to pass through the frequency selection surface or not.

(17) The present invention relates to a switching component of a directly flat-attached AFSS and fabricating method thereof, which utilizes a stepwise coating method to fabricate each layer with corresponding material, and utilizes P-type and N-type thin film materials to fabricate a PN diode switching component capable of adjusting a resonance frequency of the AFSS. Therefore, the AFSS together with the switching component could be integrally fabricated into a single thin film, and an equivalent length of a metal pattern could be adjusted, which facilitates subsequent processing and design. The switching element of the directly flat-attached active frequency selective surface of the present invention does not require a low work function metal layer in the upper portion of the component to be additionally wired and connected to a high frequency circuit wire, and could be applied to an AFSS system and module with a frequency larger than 6 GHz, and thus could be more widely applied in the future.

(18) Those skilled in the art will readily observe that numerous modifications and alterations of the device and method may be made while retaining the teachings of the invention. Accordingly, the above disclosure should be construed as limited only by the metes and bounds of the appended claims.