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E-raamat: Introduction to Magnetic Random-Access Memory [Wiley Online]

  • Formaat: 272 pages
  • Ilmumisaeg: 03-Jan-2017
  • Kirjastus: Wiley-IEEE Press
  • ISBN-10: 1119079411
  • ISBN-13: 9781119079415
  • Wiley Online
  • Hind: 132,16 €*
  • * hind, mis tagab piiramatu üheaegsete kasutajate arvuga ligipääsu piiramatuks ajaks
  • Formaat: 272 pages
  • Ilmumisaeg: 03-Jan-2017
  • Kirjastus: Wiley-IEEE Press
  • ISBN-10: 1119079411
  • ISBN-13: 9781119079415
Magnetic random-access memory (MRAM) is poised to replace traditional computer memory based on complementary metal-oxide semiconductors (CMOS). MRAM will surpass all other types of memory devices in terms of nonvolatility, low energy dissipation, fast switching speed, radiation hardness, and durability. Although toggle-MRAM is currently a commercial product, it is clear that future developments in MRAM will be based on spin-transfer torque, which makes use of electrons spin angular momentum instead of their charge. MRAM will require an amalgamation of magnetics and microelectronics technologies. However, researchers and developers in magnetics and in microelectronics attend different technical conferences, publish in different journals, use different tools, and have different backgrounds in condensed-matter physics, electrical engineering, and materials science.

This book is an introduction to MRAM for microelectronics engineers written by specialists in magnetic materials and devices. It presents the basic phenomena involved in MRAM, the materials and film stacks being used, the basic principles of the various types of MRAM (toggle and spin-transfer torque; magnetized in-plane or perpendicular-to-plane), the back-end magnetic technology, and recent developments toward logic-in-memory architectures. It helps bridge the cultural gap between the microelectronics and magnetics communities.
About The Editors xi
Preface A Perspective On Nonvolatile Magnetic Memory Technology xiii
Chapter 1 Basic Spintronic Transport Phenomena
1(28)
Nicolas Locatelli
Vincent Cros
1.1 Giant Magnetoresistance
2(7)
1.1.1 Basics of Electronic Transport in Magnetic Materials
2(3)
1.1.2 A Simple Model to Describe GMR: The "Two-Current Model"
5(2)
1.1.3 Discovery of GMR and Early GMR Developments
7(1)
1.1.4 Main Applications of GMR
8(1)
1.2 Tunneling Magnetoresistance
9(11)
1.2.1 Basics of Quantum Mechanical Tunneling
10(1)
1.2.2 First Approach to Tunnel Magnetoresistance: Julliere's Model
11(3)
1.2.3 The Slonczewski Model
14(1)
1.2.3.1 The Model
14(1)
1.2.3.2 Experimental Observations
15(1)
1.2.3.3 About the TMR Angular Dependence
15(1)
1.2.4 More Complex Models: The Spin Filtering Effect
16(1)
1.2.4.1 Incoherent Tunneling Through an Amorphous (A1203) Barrier
16(1)
1.2.4.2 Coherent Tunneling Through a Crystalline MgO Barrier
17(2)
1.2.5 Bias Dependence of Tunnel Magnetotransport
19(1)
1.3 The Spin-Transfer Phenomenon
20(9)
1.3.1 The Concept and Origin of the Spin-Transfer Effect
20(1)
1.3.1.1 The "In-Plane" Torque
20(3)
1.3.1.2 The "Out-of-Plane" Torque
23(1)
1.3.2 Spin-Transfer-Induced Magnetization Dynamics
23(1)
1.3.2.1 A Simple Analogy
24(1)
1.3.2.2 Toward MRAM Based on Spin-Transfer Torque
25(1)
1.3.3 Main Events Concerning Spin-Transfer Advances
26(1)
References
27(2)
Chapter 2 Magnetic Properties Of Materials For Mram
29(26)
Shinji Yuasa
2.1 Magnetic Tunnel Junctions for MRAM
29(2)
2.2 Magnetic Materials and Magnetic Properties
31(8)
2.2.1 Ferromagnet and Antiferromagnet
31(2)
2.2.2 Demagnetizing Field and Shape Anisotropy
33(2)
2.2.3 Magnetocrystalline Anisotropy, Interface Magnetic Anisotropy, and Perpendicular Magnetic Anisotropy
35(1)
2.2.4 Exchange Bias
36(1)
2.2.5 Interlayer Exchange Coupling and Synthetic Antiferromagnetic Structure
37(1)
2.2.6 Spin-Valve Structure
38(1)
2.3 Basic Materials and Magnetotransport Properties
39(16)
2.3.1 Metallic Nonmagnetic Spacer for GMR Spin-Valve
39(2)
2.3.2 Magnetic Tunnel Junction with Amorphous AIO Tunnel Barrier
41(3)
2.3.3 Magnetic Tunnel Junction with Crystalline MgO(0 0 1) Tunnel Barrier
44(1)
2.3.3.1 Epitaxial MTJ with a Single-Crystal MgO(0 0 1) Barrier
44(2)
2.3.3.2 CoFeB/MgO/CoFeB MTJ with a (0 0 1)-Textured MgO Barrier for Device Applications
46(2)
2.3.3.3 Device Applications of MgO-Based MTJs
48(3)
References
51(4)
Chapter 3 Micromagnetism Applied To Magnetic Nanostructures
55(24)
Liliana D. Buda-Prejbeanu
3.1 Micromagnetic Theory: From Basic Concepts Toward the Equations
55(12)
3.1.1 Free Energy of a Magnetic System
56(1)
3.1.1.1 Exchange Energy
56(1)
3.1.1.2 Magnetocrystalline Anisotropy Energy
57(1)
3.1.1.3 Demagnetizing Energy
57(3)
3.1.1.4 Zeeman Energy
60(1)
3.1.2 Magnetically Stable State and Equilibrium Equations
61(1)
3.1.3 Equations of Magnetization Motion
62(1)
3.1.4 Length Scales in Micromagnetism
63(1)
3.1.5 Modification Related to Spin-Transfer Torque Phenomena and Spin-Orbit Coupling
64(1)
3.1.6 Thermal Fluctuations
65(1)
3.1.7 Numerical Micromagnetism
66(1)
3.2 Micromagnetic Configurations in Magnetic Circular Dots
67(3)
3.3 STT-Induced Magnetization Switching: Comparison of Macrospin and Micromagnetism
70(3)
3.4 Example of Magnetization Precessional STT Switching: Role of Dipolar Coupling
73(6)
References
76(3)
Chapter 4 Magnetization Dynamics
79(22)
William E. Bailey
4.1 Landau--Lifshitz--Gilbert Equation
79(5)
4.1.1 Introduction
79(1)
4.1.2 Variables in the Equation
80(1)
4.1.3 The Equation
81(1)
4.1.3.1 Precessional Term
82(1)
4.1.3.2 Relaxation Term
83(1)
4.2 Small-Angle Magnetization Dynamics
84(6)
4.2.1 LLG for Thin-Film, Magnetized in Plane, Small Angles
84(1)
4.2.2 Ferromagnetic Resonance
85(2)
4.2.3 Tabulated Materials Parameters
87(1)
4.2.3.1 Bulk Values
87(1)
4.2.3.2 Finite-Size Effects
88(1)
4.2.4 Pulsed Magnetization Dynamics
89(1)
4.3 Large-Angle Dynamics: Switching
90(5)
4.3.1 Quasistatic Limit: Stoner--Wohlfarth Model
90(3)
4.3.2 Thermally Activated Switching
93(1)
4.3.3 Switching Trajectory
94(1)
4.4 Magnetization Switching by Spin-Transfer
95(6)
4.4.1 Additional Terms to the LLG
95(1)
4.4.2 Full-Angle LLG with Spin-Torque
96(1)
Acknowledgments
97(1)
References
97(4)
Chapter 5 Magnetic Random-Access Memory
101(64)
Bernard Dieny
I. Lucian Prejbeanu
5.1 Introduction to Magnetic Random-Access Memory (MRAM)
101(3)
5.1.1 Historical Perspective
101(1)
5.1.2 Various Categories of MRAM
102(2)
5.2 Storage Function: MRAM Retention
104(6)
5.2.1 Key Role of the Thermal Stability Factor
104(2)
5.2.2 Thermal Stability Factor for In-Plane and Out-of-Plane Magnetized Storage Layer
106(4)
5.3 Read Function
110(2)
5.3.1 Principle of Read Operation
110(1)
5.3.2 STT-Induced Disturbance of the Storage Layer Magnetic State During Read
111(1)
5.4 Field-Written MRAM (FIMS-MRAM)
112(6)
5.4.1 Stoner-Wohlfarth MRAM
112(3)
5.4.2 Toggle MRAM
115(1)
5.4.2.1 Toggle Write Principle
115(2)
5.4.2.2 Improved Write Margin
117(1)
5.4.2.3 Applications of Toggle MRAM
117(1)
5.4.3 Limitation in Downsize Scalability
118(1)
5.5 Spin-Transfer Torque MRAM (STT-MRAM)
118(17)
5.5.1 Principle of STT Writing
119(3)
5.5.2 Considerations of Breakdown, Write, Read Voltage Distributions
122(1)
5.5.3 Influence of STT Write Pulse Duration
123(1)
5.5.4 In-Plane STT-MRAM
124(1)
5.5.4.1 Critical Current for Switching
124(1)
5.5.4.2 Minimization of Critical Current for Writing
125(3)
5.5.5 Out-of-Plane STT-MRAM
128(2)
5.5.5.1 Benefit of Out-of-Plane Configuration in Terms of Write Current
130(1)
5.5.5.2 Trade-off Between Strong Perpendicular Anisotropy and Low Gilbert Damping
131(1)
5.5.5.3 Benefit from Magnetic Metal/Oxide Perpendicular Anisotropy
131(2)
5.5.5.4 Downsize Scalability of Perpendicular STT-MRAM
133(2)
5.6 Thermally-Assisted MRAM (TA-MRAM)
135(15)
5.6.1 Trade-off Between Retention and Writability; General Idea of Thermally-Assisted Writing
135(1)
5.6.2 Self-Heating in MTJ Due to High-Density Tunneling Current
136(1)
5.6.3 In-Plane TA-MRAM
136(1)
5.6.3.1 Write Selectivity Due to a Combination of Heating and Field
136(2)
5.6.3.2 Reduced Power Consumption, Thanks to Low Write Field and Field Sharing
138(2)
5.6.4 TA-MRAM with Soft Reference: Magnetic Logic Unit(MLU)
140(1)
5.6.4.1 Principle of Reading with Soft Reference
141(2)
5.6.4.2 Content-Addressable Memory
143(1)
5.6.5 Thermally-Assisted STT-MRAM
144(1)
5.6.5.1 In-Plane STT Plus TA-MRAM
144(1)
5.6.5.2 Out-of-Plane STT Plus TA-MRAM
145(5)
5.7 Three-Terminal MRAM Devices
150(3)
5.7.1 Field versus Current-Induced Domain Wall Propagation
150(2)
5.7.2 Principle of Writing
152(1)
5.7.3 Advantages and Drawbacks of Three-Terminal Devices
153(1)
5.8 Comparison of MRAM with Other Nonvolatile Memory Technologies
153(4)
5.8.1 MRAM in the International Technology Roadmap for Semiconductors (ITRS)
153(2)
5.8.2 Comparison of MRAM and Redox-RAM
155(1)
5.8.3 Main Applications of MRAM
155(2)
5.9 Conclusion
157(8)
Acknowledgments
157(1)
References
158(7)
Chapter 6 Magnetic Back-End Technology
165(34)
Michael C. Gaidis
6.1 Magnetoresistive Random-Access Memory (MRAM) Basics
165(1)
6.2 MRAM Back-End-of-Line Structures
166(3)
6.2.1 Field-MRAM
166(2)
6.2.2 Spin-Transfer Torque (STT) MRAM
168(1)
6.2.3 Other Magnetic Memory Device Structures
169(1)
6.3 MRAM Process Integration
169(18)
6.3.1 The Magnetic Tunnel Junction
169(2)
6.3.1.1 Substrate Preparation
171(1)
6.3.1.2 Film Deposition and Anneal
172(2)
6.3.1.3 Device Patterning
174(5)
6.3.1.4 Dielectric Encapsulation
179(4)
6.3.2 Wiring and Packaging
183(1)
6.3.2.1 Ferromagnetic Cladding
184(2)
6.3.2.2 Packaging
186(1)
6.3.3 Processing Cost Considerations
186(1)
6.4 Process Characterization
187(12)
6.4.1 200--300 mm Wafer Blanket Magnetic Films
187(1)
6.4.1.1 Current-in-Plane Tunneling (CIPT)
188(1)
6.4.1.2 Kerr Magnetometry
189(1)
6.4.2 Parametric Test of Integrated Magnetic Devices
189(1)
6.4.2.1 Magnetoresistance versus Resistance and Resistance versus Reciprocal Area
190(2)
6.4.2.2 Breakdown Voltage
192(2)
6.4.2.3 Device Spreads
194(1)
Acknowledgments
195(1)
References
195(4)
Chapter 7 Beyond Mram: Nonvolatile Logic-In-Memory Vlsi
199(32)
Takahiro Hanyu
Tetsuo Endoh
Shoji Ikeda
Tadahiko Sugibayashi
Naoki Kasai
Daisuke Suzuki
Masanori Natsui
Hiroki Koike
Hideo Ohno
7.1 Introduction
199(4)
7.1.1 Memory Hierarchy of Electronic Systems
199(2)
7.1.2 Current Logic VLSI: The Challenge
201(2)
7.2 Nonvolatile Logic-in-Memory Architecture
203(6)
7.2.1 Nonvolatile Logic-in-Memory Architecture Using Magnetic Flip-Flops
205(2)
7.2.2 Nonvolatile Logic-in-Memory Architecture Using MTJ Devices in Combination with CMOS Circuits
207(2)
7.3 Circuit Scheme for Logic-in-Memory Architecture Based on Magnetic Flip-Flop Circuits
209(5)
7.3.1 Magnetic Flip-Flop Circuit
209(2)
7.3.2 M-Latch
211(3)
7.4 Nonvolatile Full Adder Using MTJ Devices in Combination with MOS Transistors
214(3)
7.5 Content-Addressable Memory
217(7)
7.5.1 Nonvolatile Content-Addressable Memory
217(3)
7.5.2 Nonvolatile Ternary CAM Using MTJ Devices in Combination with MOS Transistors
220(4)
7.6 MTJ-based Nonvolatile Field-Programmable Gate Array
224(7)
References
227(4)
Appendix Units For Magnetic Properties 231(2)
Index 233
Bernard Dieny has conducted research in magnetism for 30 years. He played a key role in the pioneering work on spin-valves at IBM Almaden Research Center in 1990-1991. In 2001, he co-founded SPINTEC in Grenoble, France, a public research laboratory devoted to spin-electronic phenomena and components. Dieny is co-inventor of 70 patents and has co-authored more than 340 scientific publications. He received an outstanding achievement award from IBM in 1992 for the development of spin-valves, the European Descartes Prize for Research in 2006, and two Advanced Research Grants from the European Research Council in 2009 and 2015. He is co-founder of two companies, one dedicated to magnetic random-access memory, Crocus Technology, the other to the design of hybrid CMOS/magnetic circuits, EVADERIS. In 2011 he was elected Fellow of the Institute of Electrical and Electronics Engineers.

Ronald B. Goldfarb was leader of the Magnetics Group at the National Institute of Standards and Technology in Boulder, Colorado, USA, from 2000 to 2015. He has published over 60 papers, book chapters, and encyclopedia articles in the areas of magnetic measurements, superconductor characterization, and instrumentation. In 2004 he was elected Fellow of the Institute of Electrical and Electronics Engineers (IEEE). From 1995 to 2004 he was editor in chief of IEEE Transactions on Magnetics. He is the founder and chief editor of IEEE Magnetics Letters, established in 2010. He received the IEEE Magnetics Society Distinguished Service Award in 2016.

Kyung-Jin Lee is a professor in the Department of Materials Science and Engineering, and an adjunct professor of the KU-KIST Graduate School of Converging Science and Technology, at Korea University. Before joining the university, he worked for Samsung Advanced Institute of Technology in the areas of magnetic recording and magnetic random-access memory. His current research is focused on understanding the underlying physics of current-induced magnetic excitations and exploring new spintronic devices utilizing spin-transfer torque. He is co-inventor of 20 patents and has more than 100 scientific publications in the areas of magnetic random-access memory, spin-transfer torque, and spin-orbit torques. He received an outstanding patent award from the Korea Patent Office in 2005 and an award for Excellent Research on Basic Science from the Korean government in 2010. In 2013 he was recognized by the National Academy of Engineering of Korea as a leading scientist in spintronics, "one of the top 100 technologies of the future."