Amorphous alloy space for perpendicular MTJs

• US 9,548,445 B2
• Filed: 11/13/2015
• Issued: 01/17/2017
• Est. Priority Date: 07/27/2012
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Lee, Kangho, Chen, Wei-Chuan, Kang, Seung
• Primary Examiner(s): Islam, Mohammad
• Assistant Examiner(s): SYLVIA, CHRISTINA A
• Application Number:
  US14/940,996
• Publication Number:
  US 20160111634A1
• Time in Patent Office: 431 Days
• US Class Current: 1/1
• CPC Class Codes: G11C 11/15 using multiple magnetic layers G11C11/155 takes precedence
• CPC Class Codes: G11C 11/16 using elements in which the storage effect is based on magnetic spin effect
• CPC Class Codes: G11C 11/161 details concerning the memory cell structure, e.g. the layers of the ferromagnetic memory cell
• CPC Class Codes: H10N 50/01 Manufacture or treatment
• CPC Class Codes: H10N 50/10 Magnetoresistive devices
• CPC Class Codes: H10N 50/80 Constructional details
• CPC Class Codes: H10N 50/85 Magnetic active materials

Abstract

A perpendicular magnetic tunnel junction (MTJ) apparatus includes a tunnel magnetoresistance (TMR) enhancement buffer layer deposited between the tunnel barrier layer and the reference layers. An amorphous alloy spacer is deposited between the TMR enhancement buffer layer and the reference layers to enhance TMR. The amorphous alloy spacer blocks template effects of face centered cubic (fcc) oriented pinned layers and provides strong coupling between the pinned layers and the TMR enhancement buffer layer to ensure full perpendicular magnetization.

Claims

1. A perpendicular magnetic tunnel junction (MTJ) apparatus comprising:

a tunnel barrier layer interposed between a first free layer and a reference layer;

a first amorphous alloy perpendicular magnetic anisotropy (PMA) enhancement spacer on the first free layer;

a second free layer deposited on the PMA enhancement spacer; and

the reference layer, comprising;

a synthetic antiferromagnetic (SAF) layer;

a second amorphous alloy PMA enhancement spacer on the SAF layer; and

a tunnel magnetoresistance (TMR) enhancement buffer layer interposed between the tunnel barrier layer and the second amorphous alloy PMA enhancement spacer, in which a center layer of the TMR enhancement spacer is thicker than outer layers of the TMR enhancement spacer.

2. The apparatus of claim 1, further comprising:

an insulating capping layer directly on the second free layer.

3. The apparatus of claim 1 in which the first amorphous alloy PMA enhancement spacer comprises:

a superlattice of Fe/Ta, Co/Ta, FeB/Ta, Fe/Tan and/or FeB/Tan.

4. The apparatus of claim 1 in which the first amorphous alloy PMA enhancement spacer is between about 4 Å

and about 15 Å

thick.

5. The apparatus of claim 1 integrated into a mobile phone, a set top box, a music player, a video player, an entertainment unit, a navigation device, a computer, a hand-held personal communication systems (PCS) unit, a portable data unit, and/or a fixed location data unit.

6. A method for constructing a perpendicular magnetic tunnel junction (MTJ) apparatus, comprising:

depositing a tunnel barrier layer between a first free layer and a reference layer;

depositing a first amorphous alloy perpendicular magnetic anisotropy (PMA) enhancement spacer on the first free layer;

depositing a second free layer on the first amorphous alloy PMA enhancement spacer;

depositing a synthetic antiferromagnetic (SAF) layer on the reference layer;

depositing a second amorphous alloy PMA enhancement spacer on the SAF layer; and

depositing a tunnel magnetoresistance (TMR) enhancement buffer layer interposed between the tunnel barrier layer and the second amorphous alloy PMA enhancement spacer, in which a center layer of the TMR enhancement spacer is thicker than outer layers of the TMR enhancement spacer.

7. The method of claim 6, further comprising:

depositing an insulating capping layer directly on the second free layer.

8. The method of claim 6, further comprising:

depositing a superlattice of Fe/Ta, Co/Ta, FeB/Ta, Fe/Tan and/or FeB/Tan between the bottom free layer and the top free layer to form the first amorphous alloy PMA enhancement spacer.

9. The method of claim 6, further comprising:

depositing the first amorphous alloy PMA enhancement spacer with a thickness of 4 Å and

about 20 Å

.

10. The method of claim 6, further comprising integrating the perpendicular MTJ apparatus into a mobile phone, a set top box, a music player, a video player, an entertainment unit, a navigation device, a computer, a hand-held personal communication systems (PCS) unit, a portable data unit, and/or a fixed location data unit.

11. A perpendicular magnetic tunnel junction (MTJ) apparatus comprising:

a tunnel barrier layer interposed between a first free layer and a reference layer;

means for increasing surface anisotropy between a second free layer and the first free layer; and

the reference layer, comprising;

a synthetic antiferromagnetic (SAF) layer;

an amorphous alloy perpendicular magnetic anisotropy (PMA) enhancement spacer on the SAF layer; and

a tunnel magnetoresistance (TMR) enhancement buffer layer interposed between the tunnel barrier layer and the second amorphous PMA enhancement spacer, in which a center layer of the TMR enhancement spacer is thicker than outer layers of the TMR enhancement spacer.

12. The apparatus of claim 11 integrated into a mobile phone, a set top box, a music player, a video player, an entertainment unit, a navigation device, a computer, a hand-held personal communication systems (PCS) unit, a portable data unit, and/or a fixed location data unit.