Germanium-Based Technologies: From Materials to Devices

Copyright Page......Page 5
Germanium-Based Technologies......Page 4
Contents......Page 6
Editors......Page 14
Contributors......Page 15
List of Acronyms......Page 18
List of Symbols......Page 22
2 Historical Perspective and Milestones......Page 26
3 Ge as a Novel ULSI Substrate: Opportunities and Challenges......Page 30
4 Outline of the Book......Page 31
References......Page 34
1.1 Introduction......Page 38
1.2.1.1 Supply......Page 39
1.2.1.2 Production flow sheet......Page 41
1.2.2.1 Introduction and specific features of Czochralski Ge crystal growth......Page 43
1.2.2.2 Ge single crystals for IR optics......Page 44
1.2.2.3 HP-Ge crystals for radiation detectors......Page 45
1.2.2.4 Dislocation-free Ge crystals......Page 46
1.2.2.5 Modeling of Ge crystal growth......Page 48
1.2.3.1 Introduction......Page 49
1.2.3.2 Wafer preparation: general remarks......Page 50
1.2.3.3 Wafer preparation: process steps......Page 52
1.3 GOI Substrates......Page 57
1.3.1 Back-grind SOI......Page 58
1.3.2.2 GOI realization......Page 60
1.3.2.3 Characterization of GOI substrates......Page 61
1.4 General Conclusion......Page 63
References......Page 64
2.2 Intrinsic Point Defects in Germanium......Page 68
2.2.1 Simulation of intrinsic point defect properties......Page 69
2.2.2 Experimental data on vacancy properties......Page 70
2.2.3 Application of the Voronkov model to germanium......Page 71
2.3.2 Neutral point defects......Page 74
2.3.4 Hydrogen......Page 75
2.3.6 Nitrogen......Page 77
2.3.7 Silicon......Page 78
2.4.2 Development of mechanical stresses......Page 79
2.4.3 Mechanical properties of germanium......Page 80
2.4.4 Dislocation nucleation and multiplication during crystal pulling......Page 81
2.4.5 Electrical impact of dislocations in germanium......Page 84
2.5.1 Experimental observations of vacancy clustering......Page 86
2.5.2 Modeling and simulation of vacancy cluster formation......Page 88
References......Page 90
3.2 Diffusion in Semiconductors......Page 94
3.2.1 Diffusion mechanisms......Page 95
3.2.2 Self-diffusion......Page 96
3.3.1 Quenching......Page 99
3.3.2 Irradiation......Page 101
3.4 Self- and Group IV Diffusion in Germanium and Silicon......Page 102
3.4.1 Radioactive tracer experiments......Page 103
3.4.2 Isotope effects and Group IV (Si;Sn) diffusion in Ge......Page 104
3.4.3 Doping and pressure effects......Page 107
3.4.4 Diffusion of Ge in Si......Page 108
3.5 Solubility of Impurities in Germanium......Page 110
3.6 Diffusion of Group III and V Dopants in Germanium......Page 113
3.6.1.1 Boron......Page 114
3.6.1.2 Aluminum......Page 115
3.6.2.1 Phosphorus......Page 116
3.6.2.2 Arsenic......Page 117
3.6.3 Electric field effects on dopant diffusion in Ge......Page 118
3.6.4 Summary......Page 119
References......Page 120
4.1 Introduction......Page 124
4.2.1 Measurement of oxygen concentration......Page 125
4.2.2 Diffusion and solubility......Page 127
4.2.3 Structure of the vibration spectrum and defect model......Page 129
4.3 TDs and the Oxygen Dimer......Page 134
4.3.1 Electronic states of TDs......Page 135
4.3.2 Vibrational spectrum of TDs......Page 140
4.3.3 Vibrational spectrum of the oxygen dimer......Page 145
4.4 Infrared Absorption of Oxygen Precipitates......Page 149
4.5 The Vacancy-Oxygen Defect......Page 151
References......Page 153
5.1 Introduction......Page 158
5.2.1 Distribution coefficient k[sub(d)]......Page 159
5.2.2 Configurations of atomic Cu in Ge......Page 160
5.2.3 The dissociative copper diffusion mechanism......Page 162
5.2.4 Impact of doping density on Cu diffusion and solubility......Page 165
5.2.5 Dissociative versus kick-out mechanism for copper diffusion in germanium......Page 167
5.2.6 Precipitation of copper in germanium......Page 169
5.2.7 Energy levels and capture cross sections of substitutional copper......Page 171
5.2.8 Energy level for interstitial copper and Cu[sub(s)]-Cu[sub(i)] pairs......Page 176
5.2.9 Impact of copper on carrier lifetime in germanium......Page 178
5.3.1 Distribution coefficient, solubility and diffusivity......Page 180
5.3.2 Energy levels and capture cross sections......Page 185
5.3.3 Impact on carrier lifetime......Page 189
5.4.1 Solubility and diffusivity of Ni in Ge......Page 190
5.4.2 Energy levels and capture cross sections of Ni in Ge......Page 191
5.4.3 Impact on carrier lifetime......Page 193
5.5.1 Iron......Page 196
5.5.3 Manganese......Page 197
5.5.4.1 Chromium......Page 198
5.6.1 Electrical properties......Page 199
5.6.2 Optical properties of metals in germanium......Page 201
5.6.3 Trends in the impact on carrier lifetime in Ge......Page 202
References......Page 207
6.1 Introduction......Page 214
6.2 Quantum Mechanical Methods......Page 215
6.2.1 Clusters and supercells......Page 216
6.3 Kohn–Sham and Occupancy Levels......Page 217
6.4 Formation Energies, Vibrational Modes, Energy levels......Page 218
6.5 Defect Modeling in Ge......Page 219
6.6 Defects in Germanium......Page 220
6.6.1 Vacancies and divacancies in Ge......Page 222
6.6.3 Nitrogen defects......Page 225
6.6.5 Oxygen in germanium......Page 226
6.6.6 Thermal donors......Page 228
6.6.7 Hydrogen in germanium......Page 229
6.7 Electrical Levels of Defects......Page 230
6.8 Summary......Page 232
References......Page 233
7.1 Introduction......Page 238
7.2.1 Damage processes......Page 239
7.2.2 Comparison of electron, gamma ray, neutron and proton damage......Page 242
7.2.3 Ion-implantation damage......Page 244
7.3.1 Frenkel-pairs, the lattice vacancy, divacancy and self-interstitial atom in Ge......Page 246
7.3.2 Interaction of the intrinsic points defects with impurities in Ge......Page 248
7.3.3 Ion-implantation-induced damage: multi-vacancy and multi-self-interstitial complexes in Ge......Page 252
7.4 Effects on Devices......Page 254
References......Page 256
8.1 Introduction......Page 260
8.2 Germanium p–n Junctions......Page 261
8.2.1 Theory of a large-area p–n junction......Page 262
8.2.2 Theory of a planar p–n junction......Page 266
8.2.3 Theory of an ideal germanium p–n junction......Page 268
8.2.4 Germanium bulk p–n junction diodes......Page 269
8.2.5 State-of-the-art shallow germanium p–n junctions......Page 271
8.3.1 Equivalent oxide thickness......Page 273
8.3.2 Ge/HfO[sub(2)] gate stacks......Page 274
8.3.3 Passivation by an ultra-thin GeON interlayer......Page 275
8.3.4 Si surface passivation......Page 279
8.3.5 PH[sub(3)] surface passivation......Page 286
8.3.6 Alternative high-k on Ge......Page 287
8.4 Conclusion......Page 288
References......Page 289
9.1 Introduction......Page 294
9.2 Modeling Germanium versus Silicon......Page 295
9.3.1 Conduction band of bulk germanium......Page 297
9.3.2 Valence band of bulk germanium......Page 299
9.3.3 Energy dispersion in germanium inversion layers: electrons......Page 302
9.3.4 Energy dispersion in germanium inversion layers: holes......Page 305
9.4.1 Analytical expression for the ballistic current......Page 306
9.4.2 Results: Ge versus Si MOSFETs......Page 308
9.5 Semi-classical Transport......Page 310
9.5.1 BTE: bulk semiconductor......Page 311
9.5.3 Solution of the BTE: methods based on the moments......Page 312
9.5.4 Solution of the BTE: MC for bulk Ge......Page 313
9.5.6 Multi-subband MC......Page 315
9.6 Conclusions......Page 317
References......Page 318
10.2 Germanium Oxynitride Dielectrics......Page 322
10.2.1 Germanium oxynitride synthesis and properties......Page 323
10.2.2 Basic MOS electrical characterizations......Page 326
10.2.3 Dielectric-substrate interface analyses......Page 329
10.2.5 Summary......Page 333
10.3.1 High-k dielectrics selection criteria......Page 335
10.3.2 ALD of high-k dielectrics......Page 336
10.3.2.1 ALD of zirconia......Page 337
10.3.2.2 ALD of hafnia......Page 341
10.3.3.1 UVO of zirconia......Page 348
10.3.3.2 Zirconia–germanium interface photoemission spectroscopy......Page 350
10.3.3.3 UVO of hafnia......Page 357
10.3.4.1 Metal-organic chemical vapor deposition of hafnia......Page 358
10.3.4.2 PVD of zirconia and hafnia......Page 359
10.3.4.3 Atomic oxygen beam deposition of hafnia......Page 360
10.3.5 Nanoscale dielectrics leakage and scalability......Page 361
10.4 Shallow Junctions in Germanium......Page 364
10.4.1.1 p-type junction activation with furnace anneal......Page 366
10.4.1.2 Complementary junction activation with rapid thermal anneal......Page 369
10.4.1.3 n-type junction activation dependences......Page 371
10.4.2.1 n-type junction activation and diffusion......Page 376
10.4.2.2 Dopant deactivation within activated junctions......Page 379
10.4.3 Metal germanide contacts......Page 380
10.5 General Conclusion......Page 382
References......Page 383
11.2 The Quest for High Mobility MOSFET Channel......Page 390
11.2.1 Challenges to scaling conventional CMOS......Page 391
11.2.2 High mobility channel justification and selection......Page 394
11.3 Relaxed Bulk Channel Germanium MOSFETs......Page 395
11.3.1.2 Zirconium-based gate dielectric......Page 396
11.3.1.3 Hafnia gate dielectric......Page 398
11.3.2 n-channel MOSFETs......Page 399
11.4 Strained Epitaxial Channel Germanium MOSFETs......Page 401
11.4.2 Buried strained epitaxial channel......Page 402
11.5 Germanium-on-Insulator MOSFETs......Page 404
11.6 Schottky Source-Drain Germanium MOSFETs......Page 406
11.7 Germanium Nanowire MOSFETs......Page 409
References......Page 410
12.2 Attractive Properties for Alternative Applications......Page 414
12.2.2 Strain influence on electronic alignment......Page 415
12.2.3 Wave guiding......Page 416
12.2.4 Transport properties......Page 417
12.3.1 Integration aspects......Page 418
12.3.2 Detectors for the visible to the NIR......Page 419
12.3.3 Modulators......Page 427
12.3.4 Waveguides......Page 428
12.4 Solar Cells......Page 430
12.4.1 Tandem cells......Page 431
12.4.2 Artificial substrates for group III/V solar cells......Page 433
12.5.1 Stressors......Page 434
12.6.1 MODFET......Page 435
12.7 Spintronics......Page 437
12.8.1 Strain adjustment......Page 438
12.8.2 Thin virtual substrates......Page 439
References......Page 440
13.1 Introduction......Page 444
13.2.1 Ge condensation technique......Page 445
13.2.2 Germanium epitaxial growth on silicon......Page 446
13.3.1 GaAs and III–V on germanium FETs......Page 451
13.3.2 Germanium nanowire and QD devices......Page 453
References......Page 454
Appendix......Page 460
B......Page 468
D......Page 469
G......Page 471
I......Page 472
M......Page 473
P......Page 474
S......Page 475
Z......Page 476
Color Plates......Page 36