Method and apparatus for manufacturing magnetoresistive element

• US 20060034022A1
• Filed: 08/09/2005
• Published: 02/16/2006
• Est. Priority Date: 08/10/2004
• Status: Active Grant

• Current Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Original Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Inventors: Fukuzawa, Hideaki, Yuasa, Hiromi, Koui, Katsuhiko, Iwasaki, Hitoshi, Hashimoto, Susumu
• Granted Patent: US 7,514,117 B2
• Time in Patent Office: Days
• US Class Current: 360/324.100
• CPC Class Codes: B82Y 10/00 Nanotechnology for information processing, storage or transmission, e.g. quantum computing or single electron logic
• CPC Class Codes: B82Y 25/00 Nanomagnetism, e.g. magnetoimpedance, anisotropic magnetoresistance, giant magnetoresistance or tunneling magnetoresistance
• CPC Class Codes: G11B 2005/3996 large or giant magnetoresistive effects [GMR], e.g. as generated in spin-valve [SV] devices
• CPC Class Codes: G11B 5/3909 Arrangements using a magnetic tunnel junction
• CPC Class Codes: G11B 5/3929 Disposition of magnetic thin films not used for directly coupling magnetic flux from the track to the MR film or for shielding
• CPC Class Codes: G11C 11/161 details concerning the memory cell structure, e.g. the layers of the ferromagnetic memory cell
• CPC Class Codes: H10B 61/10 comprising components having two electrodes, e.g. diodes or MIM elements
• CPC Class Codes: H10B 61/22 of the field-effect transistor [FET] type
• CPC Class Codes: H10N 50/01 Manufacture or treatment
• CPC Class Codes: H10N 50/10 Magnetoresistive devices
• CPC Class Codes: Y10T 428/115 Magnetic layer composition

Abstract

The present invention relates to a method for manufacturing a magnetoresistive element having a magnetization pinned layer, a magnetization free layer, and a spacer layer including an insulating layer provided between the magnetization pinned layer and the magnetization free layer and current paths penetrating into the insulating layer. A process of forming the spacer layer in the method includes depositing a first metal layer forming the metal paths, depositing a second metal layer on the first metal layer, performing a pretreatment of irradiating the second metal layer with an ion beam or a RF plasma of a rare gas, and converting the second metal layer into the insulating layer by means of supplying an oxidation gas or a nitriding gas.

Claims

1. A method for manufacturing a magnetoresistive element comprising a magnetization pinned layer a magnetization direction of which is substantially pinned in one direction, a magnetization free layer a magnetization direction of which varies depending on an external field, and a spacer layer including an insulating layer provided between the magnetization pinned layer and the magnetization free layer and current paths penetrating into the insulating layer, the method comprising:

depositing a second metal layer on a first metal layer; and

causing the first metal layer to penetrate into the second metal layer as the metal paths and converting the second metal layer into the insulating layer by means of supplying an oxidation gas or a nitriding gas.

3. The method according to claim 1, further comprising:

performing a pretreatment of irradiating the second metal layer with an ion beam or a RF plasma of a rare gas prior to the converting step.

2. A method for manufacturing a magnetoresistive element comprising a magnetization pinned layer a magnetization direction of which is substantially pinned in one direction, a magnetization free layer a magnetization direction of which varies depending on an external field, and a spacer layer including an insulating layer provided between the magnetization pinned layer and the magnetization free layer and current paths penetrating into the insulating layer, the method comprising a process of forming the spacer layer comprising:

depositing a first metal layer forming the metal paths;

depositing a second metal layer on the first metal layer;

performing a pretreatment of irradiating the second metal layer with an ion beam or a RF plasma of a rare gas; and

converting the second metal layer into the insulating layer by means of supplying an oxidation gas or a nitriding gas.

4. The method according to claim 2, wherein the pretreatment is performed with an acceleration voltage for the ion beam or the RF plasma of the rare gas setting to 30 V or more and 130 V or less.

5. The method according to claim 4, wherein the pretreatment is performed with the acceleration voltage for the ion beam or the RF plasma of the rare gas setting to 40 V or more and 60 V or less.

6. The method according to claim 2, wherein the converting step is performed by supplying the oxidation gas or the nitriding gas while irradiating the second metal layer with the ion beam or the RF plasma of the rare gas.

7. The method according to claim 6, wherein the converting step is performed with an acceleration voltage for the ion beam or the RF plasma of the rare gas setting to 40 V or more and 200 V or less.

8. The method according to claim 7, wherein the converting step is performed with the acceleration voltage for the ion beam or RF plasma of the rare gas setting to 50 V or more and 100 V or less.

9. The method according to claim 2, wherein the first metal layer contains at least one element selected from the group consisting of Cu, Au, and Ag.

10. The method according to claim 2, wherein the first metal layer has a thickness of 0.1 nm or more and 1 nm or less.

11. The method according to claim 2, wherein the insulating layer is an oxide or a nitride containing at least one element selected from the group consisting of Al, Si, Hf, Ti, Ta, Mo, W, Nb, Mg, Cr, and Zr.

12. The method according to claim 2, wherein the second metal layer is formed of Al_xCu_100-x, where 70≦

x≦

100 atomic %.

13. The method according to claim 2, wherein the second metal layer has a thickness of 0.5 nm or more and 2 nm or less.

14. The method according to claim 2, wherein the current paths have a diameter of 2 nm or more and 6 nm or less.

15. The method according to claim 2, wherein the magnetization pinned layer has a body-centered cubic structure at an interface with the spacer layer.

16. The method according to claim 2, wherein the magnetization pinned layer comprises a Fe_xCo_100-x alloy layer, where x≧

30 atomic %.

17. The method according to claim 2, wherein the magnetization pinned layer includes a stacked film of a ferromagnetic layer and a Cu layer with a thickness of 0.1 nm or more and 1 nm or less.

18. The method according to claim 2, further comprising:

forming a Cu layer on the spacer layer.

19. The method according to claim 18, wherein the Cu layer has a thickness of 0.1 nm or more and 0.5 nm or less.

20. An apparatus for manufacturing a magnetoresistive element using the method according to claim 2, the apparatus comprising:

a load lock chamber to which a substrate is loaded;

a depositing chamber in which a metal layer is deposited on the substrate;

a reaction chamber comprising a supplier supplying an oxidation gas or a nitriding gas and an ion source which excites a rare gas to generate plasma and irradiates the metal layer with an ion beam; and

a substrate transfer chamber connected to the chambers via vacuum valves.

21. The apparatus according to claim 20, wherein the ion source in the reaction chamber comprises a grid which controls an acceleration voltage for the ion beam within a range of 30 V or more and 200 V or less.

22. The apparatus according to claim 20, further comprising an electron emitter arranged between the grid and a substrate table on which the substrate is placed, wherein electrons emitted by the electron emitter are allowed to flow into the ion source.

23. A magnetoresistive element, comprising:

a lower electrode;

an underlayer;

a pinning layer comprising an antiferromagnetic layer represented by MeMn, where Me is Ir or Pt;

a first magnetization pinned layer formed of a CoFe alloy layer;

a Ru layer;

a second magnetization pinned layer formed of a FeCo alloy layer with a thickness of 2.5 to 4 nm having a bcc structure a magnetization direction of which is substantially pinned in one direction;

a lower Cu layer;

a spacer layer comprising an Al₂O₃ layer and Cu current paths penetrating the Al₂O₃ layer;

an upper Cu layer;

a magnetization free layer formed of a stack of a CoFe alloy layer with a thickness of 0.5 to 2 nm and a NiFe layer a magnetization direction of which varies depending on an external field;

a cap layer comprising a Cu layer or a Ru layer; and

an upper electrode.