Electrical Atomic Force Microscopy for Nanoelectronics (eBook)

Contents 6
Contributors 14
Acronyms 17
1 The Atomic Force Microscopy for Nanoelectronics 21
1.1 Introduction 21
1.2 Atomic Force Microscopy: The Swiss-Knife of Nanoelectronics 23
1.3 Introduction to Atomic Force Microscopy 27
1.3.1 Basic Operating Principles 27
1.3.2 To Touch, or Not To Touch, That Is the Question 30
1.3.3 Mechanisms of Contrast Formation 32
1.3.4 Effective Voltage Drop, Phantom Force, and Biasing Schemes 38
1.4 Emerging Nanoelectronics Devices and Metrology Challenges 39
1.4.1 Device Scaling: An Increasingly Difficult Miniaturization Landscape 40
1.4.2 New Devices Based on New Physics 41
1.5 Present Status and Future Applications 42
References 44
2 Conductive AFM for Nanoscale Analysis of High-k Dielectric Metal Oxides 49
2.1 The C-AFM Technique 50
2.1.1 AFM in Contact Mode with Conducting Tips 50
2.1.2 C-AFM Modes 52
2.1.3 Electronics 53
2.1.4 Analysis of the Tip Sample Interaction: Energy Barriers 57
2.1.5 Requirements for Sample Preparation—The Role of Adsorbates 59
2.1.6 C-AFM with Atomic Resolution 60
2.2 Basics of High-k Dielectrics 62
2.2.1 Scaling Limits and Challenges in Semiconductor Technology 62
2.2.2 Technologically Relevant Metal Oxides with High k 63
2.2.3 Synthesis of Metal Oxides 64
2.3 Local Analysis of Electronic Transport Properties in Metal Oxide Thin Films 66
2.3.1 Variation of Nanoscale Conductivity Seen by Nanoelectrodes 66
2.3.2 Localized Nature of Leakage Current 66
2.3.3 Correlation of the Localized Conductivity with the Surface Potential 69
2.3.4 Tuning the Conductivity by Thermal Annealing 71
2.3.5 Confinement of Conductivity at Surfaces and Interfaces 73
2.4 Influence of Extended Defects on the Local Conductivity of Single Crystals 75
2.4.1 Current Channelling Along Dislocations 75
2.4.2 Analysis of Bulk Conductivity by the Cleaving Method 76
2.4.3 Ferroelectric Domain Walls as Conducting Paths 77
2.5 Manipulation of the Conductivity by C-AFM 80
2.5.1 Tip-Induced Memristive Switching of Single Dislocations in SrTiO3 80
2.5.2 Creation of Conducting Nanowires on LAO/STO Structures 82
2.5.3 Electrical Nanopatterning of Oxide Surfaces 83
References 86
3 Mapping Conductance and Carrier Distributions in Confined Three-Dimensional Transistor Structures 91
3.1 Introduction: The Fundamentals of SSRM 92
3.1.1 Basic Principles 92
3.1.2 Physics of the Nanoscale SSRM Contact 94
3.1.3 Quantification 98
3.1.4 Practical Aspects 100
3.1.5 Application to Planar Transistor Technologies 103
3.2 SSRM Applied to 3D Transistor Architectures 103
3.2.1 CMOS Scaling and the Advent of 3D Devices 104
3.2.2 Revisiting Dopant Metrology Requirements 105
3.2.3 Understanding Dopant Incorporation and Activation in 3D Structures 106
3.2.4 Tomographic Carrier Mapping 111
3.2.5 Outsmarting Parasitic Resistances: Fast Fourier Transform-SSRM 115
3.2.6 Toward Holistic Transistor Metrology: Combining TEM and SSRM 120
3.3 Summary 122
References 123
4 Scanning Capacitance Microscopy for Two-Dimensional Carrier Profiling of Semiconductor Devices 127
4.1 Working Principle of Scanning Capacitance Microscopy 127
4.2 Applications of Scanning Capacitance Microscopy 130
4.2.1 Effect of Hot Carrier Stress on Device Junctions 130
4.2.2 Root Cause Analysis for Pin Leakage 137
4.2.3 Junction Profiling of Ge Photodetector Structures Using Scanning Capacitance Microscopy and Electron Holography 147
4.2.4 Innovative Use of FA Techniques to Resolve Junction Scaling Issues at Advanced Technology Nodes 155
4.3 Summary 161
References 161
5 Oxidation and Thermal Scanning Probe Lithography for High-Resolution Nanopatterning and Nanodevices 163
5.1 Introduction 163
5.2 Oxidation Scanning Probe Lithography: Direct Chemical Modification at the Nanoscale 165
5.2.1 Mechanism and Growth Kinetics. Oxidation Parameters and Operation Modes 165
5.2.2 Materials Modified by Oxidation Scanning Probe Lithography 171
5.3 Thermal Scanning Probe Lithography: Fast Turnaround Nanofabrication in Ambient Conditions Combining Thermal Probes and Focused Lasers 178
5.4 Conclusion. Strengths and Limitations of SPL 181
References 183
6 Characterizing Ferroelectricity with an Atomic Force Microscopy: An All-Around Technique 193
6.1 Introduction 194
6.2 Piezoresponse Force Microscopy as a Domain Imaging Technique 194
6.2.1 Principles of Imaging Ferroelectric Domains 194
6.2.2 The Converse Piezoelectric Effect as Imaging Technique 195
6.2.3 Piezoresponse as a Quantitative Technique 197
6.2.4 Practical Aspects for Doing PFM 199
6.3 The Nano-PUND Technique 202
6.3.1 The Principle of PUND Measurement 203
6.3.2 Nano-PUND: PUND Method Implemented in an AFM 204
6.3.3 Examples and Applications of Nano-PUND Measurements 205
6.3.4 Future Developments of Nano-PUND Technique 207
6.4 Direct Piezoelectric Force Microscopy as a Quantitative Tool 208
6.4.1 Principles of DPFM 208
6.4.2 Quantitative Data in DPFM 212
6.4.3 Practical How-to Guide for Imaging with DPFM 213
6.5 Applications of Nanoscale Ferroelectric Characterization into Semiconductors 216
6.5.1 Solar Cells 216
6.5.2 Sensors 218
6.5.3 Negative Capacitance 218
References 220
7 Electrical AFM for the Analysis of Resistive Switching 224
7.1 Introduction to Resistive Switching 224
7.1.1 Devices and Applications 225
7.1.2 Physics of Resistive Switching 226
7.2 AFM Experimental Setup for Resistive Switching Characterization 228
7.2.1 Advantages of AFM 228
7.2.2 Contact AFM Techniques 228
7.2.3 Non-contact AFM Techniques 230
7.3 Noteworthy AFM Scientific Results 231
7.3.1 Interfacial Switching 232
7.3.2 Filamentary Switching 233
7.3.3 C-AFM as a Nano-probe for Critical Morphologies 240
7.4 Conclusions 243
7.5 Perspectives 244
References 244
8 Magnetic Force Microscopy for Magnetic Recording and Devices 249
8.1 Introduction 249
8.1.1 Magnetic Imaging 250
8.1.2 Magnetic Force Microscopy 251
8.1.3 Other SPM-Based Magnetic Microscopy 252
8.2 Principles of Non-contact/Tapping Mode 255
8.2.1 Principles of Non-contact Atomic Force Microscopy 255
8.2.2 Principles of Magnetic Force Microscopy 256
8.3 Magnetic Tips and Specifications 259
8.3.1 Magnetic Tips 259
8.3.2 Improvement of Specifications 269
8.4 Applications for Magnetic Recording 269
8.4.1 3.5-in. Floppy Disk Introduced in 1987 270
8.4.2 Zip Drive Introduced in 1994 271
8.4.3 Fujitsu HDD Introduced in 2007 272
8.4.4 Seagate HDD Introduced in 2009 274
8.4.5 Western Digital HDD Introduced in 2012 274
8.4.6 Seagate HDD Introduced in 2016 274
8.4.7 Outlook 275
8.5 Applications for Magnetic Memories and Devices 277
8.5.1 Magnetic Random Access Memory and Spin Random Access Memory 277
8.5.2 Racetrack Memory 278
8.5.3 Magnetic Skyrmion Logics 279
References 281
9 Space Charge at Nanoscale: Probing Injection and Dynamic Phenomena Under Dark/Light Configurations by Using KPFM and C-AFM 284
9.1 Context 285
9.1.1 Miniaturization of Thin Dielectric Layers 285
9.1.2 Interfaces 286
9.2 KPFM and C-AFM Measurement Under Dark and Light Configurations 287
9.2.1 Introduction to Surface Potential 287
9.2.2 Surface Potential Measurement in AM-KPFM 288
9.2.3 Surface Potential Measurement in FM-KPFM 291
9.2.4 Surface Potential Measurement in PF-KPFM 291
9.2.5 Photoconductive and Photo-KPFM Modes 293
9.2.6 KPFM Modelling 294
9.3 Local Charges Injection Mechanisms 295
9.3.1 Local Injection Using Conductive AFM-Tip and Surface Potential Measurements 296
9.3.2 Charges Injection and Decay in Thin Dielectric Layers 300
9.4 KPFM for Space Charge Probing in Semiconductor and Dielectric Materials 304
9.4.1 KPFM Measurements on Bias Electronic Devices: Challenge and Bottleneck 304
9.4.2 Methodology for Charge Density Profile Determination from KPFM Measurements 304
9.4.3 Applications to Dielectrics and Semiconductors 306
9.5 Nanoscale Opto-Electrical Characterization of Thin Film Based Solar Cells Using KPFM and C-AFM 309
9.5.1 Mapping Measurements 309
9.5.2 Localized Current-Voltage Measurements 310
9.6 Conclusion and Overview 312
References 313
10 Conductive AFM of 2D Materials and Heterostructures for Nanoelectronics 319
10.1 Introduction 319
10.2 Large Area Synthesis of Graphene, MoS2 and h-BN for Electronics 322
10.3 Overview of 2D Materials-Based Electronic Devices 326
10.3.1 Graphene FETs for High Frequency Electronics 326
10.3.2 2D-Semiconductors FETs for Digital Electronics 327
10.3.3 Vertical Transistors Based on 2D-Materials Heterostructures 329
10.3.4 Transistors Based on 2D Materials Heterojunctions with Bulk Semiconductors 331
10.4 C-AFM Applications to 2D Material and Devices: Case Studies 335
10.4.1 Nanoscale Mapping of Transport Properties in Graphene and MoS2 335
10.4.2 Vertical Current Injection Through 2D/3D or 2D/2D Materials Heterojunctions 344
10.4.3 Electrical Characterization of h-BN as Two Dimensional Dielectric: Lateral Inhomogeneity, Reliability and Dielectric Breakdown 349
10.5 Summary 358
References 359
11 Diamond Probes Technology 367
11.1 Introduction 368
11.2 Molded Diamond Tip Probes 370
11.2.1 Basic Fabrication Process 371
11.2.2 Probe Process Variations 374
11.2.3 Fabrication Results 375
11.3 Probe Characterization 379
11.3.1 Probe Storage Considerations 380
11.4 Conclusions on Molded Diamond Probes 384
11.5 Plasma Etched Single Crystal Doped Diamond Probes 384
11.5.1 Manufacturing 385
11.6 Applications 388
11.6.1 Scanning Tunneling Microscopy—Atomic Resolution Imaging 389
11.6.2 Conductive Atomic Force Microscopy 389
11.6.3 Scanning Capacitance Microscopy 390
11.6.4 Scanning Spreading Resistance Microscopy 393
11.6.5 Measurement of High Aspect Ratio Structures 393
11.7 Conclusions and Outlook 396
References 397
12 Scanning Microwave Impedance Microscopy (sMIM) in Electronic and Quantum Materials 401
12.1 Introduction 401
12.2 Theory of Operation—sMIM 402
12.2.1 Working Principal of sMIM 402
12.2.2 Contrast Mechanism 404
12.2.3 Technique Benefits 405
12.2.4 Single Electrode Measurement 405
12.2.5 Measuring Buried Structures 405
12.2.6 Monotonic with Permittivity 407
12.2.7 Monotonic with Log Doping Concentration 408
12.3 Characterization of Nanomaterials with sMIM 411
12.3.1 Dielectric Materials 411
12.3.2 Semiconducting Materials 411
12.3.3 2D Materials 414
12.3.4 Quantum Materials 416
12.4 Summary and Conclusion 419
References 421