Claims
- 1. A method of forming a high-T.sub.c superconducting junction, the method comprising the steps of:
- a) depositing a first high-T.sub.c superconductive layer on a surface of a substrate, the first high-T.sub.c superconductive layer having a first thickness;
- b) depositing a dielectric layer on the first high-T.sub.c superconductive layer;
- c) forming a ramp edge on the first high-T.sub.c superconductive layer and the dielectric layer, the ramp edge being inclined relative to the surface of the substrate;
- d) depositing a second high-T.sub.c superconductive layer on the ramp edge, the second high-T.sub.c superconductive layer having a second thickness less than the first thickness;
- e) depositing a conductive barrier layer on the second high-T.sub.c superconductive layer, the barrier layer being comprised of a normal material that is non-superconductive at the operating temperature of the superconducting junction; and
- f) depositing a third high-T.sub.c superconductive layer on the barrier layer.
- 2. The method of claim 1, wherein the first high-T.sub.c superconductive layer, the second high-T.sub.c superconductive layer and the third high-T.sub.c superconductive layer are comprised of the same high-T.sub.c superconductive material.
- 3. The method of claim 2, wherein the high-T.sub.c superconductive material is a material selected from the group consisting of YBCO; A.sub.2 B.sub.2 Ca.sub.n Cu.sub.n+1 O.sub.2n+6, where n=0, 1, 2, 3 or 4, A=Bi or Tl, and B=Sr or Ba; and LnBa.sub.2 Cu.sub.3 O.sub.7-x, where Ln=Nd, Sm, Er, Gd, Dy, Ho, Er, Tm or Lu.
- 4. The method of claim 3, wherein the dielectric layer is comprised of a material selected from the group consisting of SrTiO.sub.3, LaAlO.sub.3, neodymium gallate and strontium aluminum tantalate, and the barrier layer is comprised of a material selected from the group consisting of cobalt-doped YBCO, cobalt-doped PBCO and gallium-doped PBCO.
- 5. The method of claim 1, wherein the second high-T.sub.c superconductive layer is deposited to a thickness of from about 100 .ANG. to about 1000 .ANG..
- 6. The method of claim 5, wherein the second high-T.sub.c superconductive layer is deposited to a thickness of less than about 500 .ANG..
- 7. The method of claim 1, wherein the ramp edge is oriented at an angle of from about 5.degree. to about 30.degree. relative to the surface of the substrate.
- 8. The method of claim 1, wherein the second high-T.sub.c superconductive layer, the barrier layer and the third high-T.sub.c superconductive layer are formed in-situ on the ramp edge.
- 9. The method of claim 1, further comprising the step of implanting a species at selected regions of the second high-T.sub.c superconductive layer, the species being effective to make the selected regions non-superconductive at the operating temperature of the superconducting junction.
- 10. The method of claim 1, wherein the first high-T.sub.c superconductive layer, the second high-T.sub.c superconductive layer, the barrier layer and the third high-T.sub.c superconductive layer are epitaxially deposited so as to have a c-axis substantially normal to the surface of the substrate.
- 11. The method of claim 1, wherein steps (c)-(f) are performed in-situ in a cluster tool system.
- 12. A method of forming a high-T.sub.c superconducting junction, the method comprising the steps of:
- a) depositing a first high-T.sub.c superconductive layer on a surface of the substrate, the first high-T.sub.c superconductive layer having a first thickness;
- b) depositing a dielectric layer on the first high-T.sub.c superconductive layer;
- c) forming a patterned photoresist layer on the dielectric layer;
- d) forming a ramp edge on the first high-T.sub.c superconductive layer and the dielectric layer, the ramp edge being inclined relative to the surface of the substrate;
- e) generating a plasma of an oxygen-containing gas and contacting the photoresist layer with the plasma to remove the photoresist layer on the dielectric layer;
- f) depositing a second high-T.sub.c superconductive layer on the ramp edge, the second high-T.sub.c superconductive layer having a second thickness less than the first thickness;
- g) depositing a conductive barrier layer on the ramp edge, the barrier layer being comprised of a normal material that is non-superconductive at the operating temperature of the superconducting junction; and
- h) depositing a third high-T.sub.c superconductive layer on the barrier layer;
- i) wherein steps (d)-(f) are performed in-situ in a cluster tool system.
Parent Case Info
This application is a division of application Ser. No. 08/761,412, filed on Dec. 6, 1996, now U.S. Pat. No. 5,892,243.
US Referenced Citations (23)
Foreign Referenced Citations (1)
Number |
Date |
Country |
10-173246 |
Jun 1998 |
JPX |
Non-Patent Literature Citations (3)
Entry |
Reagor et al, Appl. Phys. lett. 66(17) p. 2280-2282, Apr. 1995. |
Char et al., Appl.Phyo.lett. 62(2), p. 196-198, Jan. 1993. |
Strikovskiy, M.D. et al., "Ramp-type YBa.sub.2 Cu.sub.3 O.sub.7-.delta. Josephson junctions with high characteristic voltage, fabricated by a new, completely in situ, growth technique," Appl. Phys. Lett. 69(19):2918-2920 (Nov. 4, 1996). |
Divisions (1)
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Number |
Date |
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Parent |
761412 |
Dec 1996 |
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