Multilayer structure with zirconium-oxide tunnel barriers and applications of same

• US 7,977,668 B2
• Filed: 05/23/2008
• Issued: 07/12/2011
• Est. Priority Date: 05/23/2007
• Status: Expired due to Fees

• Current Assignee: Northwestern University
• Original Assignee: Northwestern University
• Inventors: Chernyashevskyy, Oleksandr, Nevirkovets, Ivan, Ketterson, John, Shafraniuk, Serhii
• Primary Examiner(s): Wojciechowicz; Edward
• Application Number:
  US12/126,726
• Publication Number:
  US 20090057652A1
• Time in Patent Office: 1,145 Days
• Field of Search: 257/30, 257/31, 257/32, 257/35
• US Class Current: 257/31
• CPC Class Codes: B82Y 10/00 Nanotechnology for information processing, storage or transmission, e.g. quantum computing or single electron logic
• CPC Class Codes: G06N 10/00 Quantum computing, i.e. information processing based on quantum-mechanical phenomena
• CPC Class Codes: H10N 60/0912 of Josephson-effect devices
• CPC Class Codes: H10N 60/12 Josephson-effect devices
• CPC Class Codes: Y10T 29/49014 Superconductor

Abstract

A multilayer structure with zirconium-oxide tunnel barriers. In one embodiment, the multilayer structure includes a first niobium (Nb) layer, a second niobium (Nb) layer, and a plurality of zirconium-oxide tunnel barriers sandwiched between the first niobium (Nb) layer and the second niobium (Nb) layer, wherein the plurality of zirconium-oxide tunnel barriers is formed with N layers of zirconium-oxide, N being an integer greater than 1, and M layers of zirconium, M being an integer no less than N, such that between any two neighboring layers of zirconium-oxide, a layer of zirconium is sandwiched therebetween.

Claims

1. A multilayer structure with zirconium-oxide tunnel barriers, comprising:

(a) a first niobium (Nb) layer;

(b) a second niobium (Nb) layer; and

(c) a stack of alternating layers of zirconium (Zr) and zirconium-oxide formed on the first niobium (Nb) layer by sequentially depositing a plurality of zirconium (Zr) layers followed by oxidation after each deposition and sandwiched between the first niobium (Nb) layer and the second niobium (Nb) layer, wherein the total number of layers of zirconium-oxide in the stack is greater than or equal to two, and each layer of zirconium (Zr) has a thickness that is less than 1 nm.

2. The multilayer structure of claim 1, wherein each layer of zirconium-oxide is formed by oxidizing a layer of zirconium that is deposited on another layer of zirconium or one of the first niobium (Nb) layer and the second niobium (Nb) layer, and wherein the oxidation of a layer of zirconium is performed at a range of rate about 150 to 1500 Pa s.

3. The multilayer structure of claim 1, wherein each of the first niobium (Nb) layer and the second niobium (Nb) layer has a thickness, D, in the range of about 50 to 200 nm.

4. The multilayer structure of claim 3, wherein each of N layers of zirconium-oxide and M layers of zirconium has a thickness, d, which satisfies the relationship D/d≧

10.

5. The multilayer structure of claim 1, further comprising a substrate, and wherein the first niobium (Nb) layer is deposited on the substrate.

6. A multilayer structure with zirconium-oxide tunnel barriers, comprising:

(a) a first layer of metallic material;

(b) a second layer of metallic material; and

(c) a stack of alternating layers of zirconium (Zr) and zirconium-oxide formed on the first layer of metallic material by sequentially depositing a plurality of zirconium (Zr) layers followed by oxidation after each deposition and sandwiched between the first layer of metallic material and the second layer of metallic material, wherein the total number of layers of zirconium-oxide in the stack is greater than or equal to two, and each layer of zirconium (Zr) has a thickness that is less than 1 nm.

7. The multilayer structure of claim 6, wherein each layer of zirconium-oxide is formed on a layer of zirconium or one of the first layer of metallic material and the second layer of metallic material.

8. The multilayer structure of claim 6, wherein each of the first layer of metallic material and the second layer of metallic material has a thickness, D, in the range of about 50 to 200 nm.

9. The multilayer structure of claim 8, wherein each of N layers of zirconium-oxide and M layers of zirconium has a thickness, d, which satisfies the relationship D/d≧

10.

10. The multilayer structure of claim 6, further comprising a substrate, and wherein the first layer of metallic material is deposited on the substrate.

11. The multilayer structure of claim 10, wherein each of the first layer of metallic material and the second layer of metallic material is selected from the group of metals consisting of niobium, niobium plus nitrogen, niobium plus tin, vanadium plus silicon, niobium plus nitrogen and carbon, niobium plus germanium, and niobium plus germanium and silicon.