Ultrathin perpendicular pinned layer structure for magnetic tunneling junction devices

• US 9,634,237 B2
• Filed: 12/23/2014
• Issued: 04/25/2017
• Est. Priority Date: 12/23/2014
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Lee, Kangho, Kan, Jimmy, Zhu, Xiaochun, Gottwald, Matthias Georg, Park, Chando, Kang, Seung Hyuk
• Primary Examiner(s): Valentine, Jami M
• Application Number:
  US14/581,361
• Publication Number:
  US 20160181508A1
• Time in Patent Office: 854 Days
• Field of Search: 257 20, 257414, 257421-427, 257E2932, 438 3, 365157-158, 365171-173, 360324-326, 360313
• CPC Class Codes: G11C 11/161 details concerning the memory cell structure, e.g. the layers of the ferromagnetic memory cell
• CPC Class Codes: H01F 10/3272 by use of anti-parallel coupled [APC] ferromagnetic layers, e.g. artificial ferrimagnets [AFI], artificial [AAF] or synthetic [SAF] anti-ferromagnets
• CPC Class Codes: H01F 10/3286 Spin-exchange coupled multilayers having at least one layer with perpendicular magnetic anisotropy
• CPC Class Codes: H01F 41/305 applying the spacer or adjusting its interface, e.g. in order to enable particular effect different from exchange coupling
• CPC Class Codes: H10B 61/00 Magnetic memory devices, e.g. magnetoresistive RAM [MRAM] devices
• 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 material stack of a synthetic anti-ferromagnetic (SAF) reference layer of a perpendicular magnetic tunnel junction (MTJ) may include an SAF coupling layer. The material stack may also include and an amorphous spacer layer on the SAF coupling layer. The amorphous spacer layer may include an alloy or multilayer of tantalum and cobalt or tantalum and iron or cobalt and iron and tantalum. The amorphous spacer layer may also include a treated surface of the SAF coupling layer.

Claims

1. A material stack of a synthetic anti-ferromagnetic (SAF) reference layer of a perpendicular magnetic tunnel junction (MTJ), the material stack comprising:

an SAF coupling layer;

a coupling enhancement layer comprising a single layer directly on the SAF coupling layer;

an amorphous spacer layer directly on the coupling enhancement layer, in which the amorphous spacer layer comprises an alloy or multilayer comprising tantalum and cobalt or tantalum and iron or cobalt and iron and tantalum; and

no repetitions of a perpendicular magnetic anisotropy (PMA) multilayer within an anti-parallel pinned layer directly on the SAF coupling layer.

2. The material stack of claim 1, in which the amorphous spacer layer is configured to maintain or increase tunneling magneto resistance (TMR) provided by the material stack having a reduced thickness during an annealing process.

3. The material stack of claim 1, in which the coupling enhancement layer comprises a single PMA layer between the SAF coupling layer and the amorphous spacer layer.

5. The material stack 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 system (PCS) unit, a portable data unit, and/or a fixed location data unit.

4. A material stack of a synthetic anti-ferromagnetic (SAF) reference layer of a perpendicular magnetic tunnel junction (MTJ), the material stack comprising:

an SAF coupling layer;

an amorphous spacer layer on the SAF coupling layer, the amorphous spacer layer comprising an alloy or multilayer comprising tantalum and cobalt or tantalum and iron or cobalt and iron and tantalum;

a plurality of repetitions of perpendicular magnetic anisotropy (PMA) multilayers within a first anti-parallel pinned layer (AP1) directly coupled to the SAF coupling layer; and

no repetitions of the PMA multilayers within a second anti-parallel pinned layer (AP2) on the SAF coupling layer.