Contamination aspects in integrating high dielectric constant and ferroelectric materials into CMOS processes [Elektronische Ressource] / vorgelegt von Hocine Boubekeur

Boubekeur_50869

Informations

• Publié par: friedrich-alexander-universitat_erlangen-nurnberg
• Publié le: 01 janvier 2004
• Nombre de lectures: 30
• Langue: English
• Poids de l'ouvrage: 5 Mo

Extrait

Contamination Aspects in Integrating High
Dielectric Constant and Ferroelectric
Materials into CMOS Processes
Der Technischen Fakultät der
Universität Erlangen-Nürnberg
zur Erlangung des Grades
DOKTOR-INGENIEUR
vorgelegt von
Hocine Boubekeur
Erlangen 2002Als Dissertation genehmigt von
der Technischen Fakultät der
Universität Erlangen-Nürnberg
Tag der Einreichung: 20.09.2001
Tag der Promotion: 05.03.2002
Dekan: Prof. Dr.-Ing. W. Glauert
1. Berichterstatter: Prof. Dr.-Ing. H. Ryssel
2. Berichterstatter: Prof. Dr. I. Eisele
Weiteres prüfungsberechtigtes Mitglied Prof. Dr. A. Winnacker Acknowledgments
First and foremost, I am enduringly grateful to my advisor Prof. Dr.-Ing. H. Ryssel, for
the opportunity to undertake this research work under his supervision. His guidance
and support made this work possible.
I am also indebted to Dr. Thomas Mikolajick and Dr. Lothar Frey, who clarified many
points in this research. The contribution of Thomas and Lothar to this thesis has been
not only through many hours of detailed discussions, but also through continuous
encouragement and endless support. My interaction with them has been a precious
learning experience.
I owe many thanks to Dr. Werner Pamler for the invaluable support and stimulating
suggestions to this research. The numerous discussions with him have enriched my
academic experience.
I thank Prof. Dr. I. Eisele for kindly agreeing to serve on my thesis committee and for
the expertise to the evaluation of this work.
I am sincerely grateful to Dr. Christine Dehm and Joachim Höpfner for administration
assistance and advice. I am also very grateful to Dr. Helmut Klose for his interest in
the progress of this work.
The work presented in this dissertation would not have been possible without the
contribution of many individuals. I wish to thank Barbara Hasler for introducing me to
the production line and pointing me in the right direction as I started the fabrication of
the test structure. Specifically, I thank Dr. Joseph Steiner, Dr. Rolf Treichler, Dr.
Franz Jahnel, Dr. Andreas Rucki, and Dr. Wolfgang Hösler for efficiently performing
countless measurements. A large amount of thanks goes to the clean room staff of
Fraunhofer Institute of Integrated Circuit. I would like to thank Dr. Anton Bauer, Katrin
Fischer, Stephanie Natzer, Dagmar Kraus, Mathias Rommel, Fabian Quast, Holger
Kotouc, and Gudrun Rattmann for their help.
No amount of gratitude would be sufficient for my parents, brothers, and sisters. I
dedicate this thesis to them in appreciation of their constant encouragement and
support in all aspects of my life. My mother for setting a remarkable example to
follow. Contents
Abstract...................................................................................................................iii
Zusammenfassung (Abstract in German).............................................................. iv
1 Introduction ............................................................................................................ 1
2 Advanced Memory Concepts and New Materials for Giga-Bit Scale Memories..... 6
2.1 The Evolution of Dynamic Random Access Memories...................................... 6
2.2 High Dielectric Constant Materials .................................................................... 7
2.3 Non Volatile Ferro-Electric Memories................................................................ 9
2.4 Integration Aspects of High Dielectric Constant and Ferroelectric Films in
CMOS Processes.................................................................................................. 11
2.4.1 Barium Strontium Titanate and Strontium Bismuth Tantalate ................... 13
2.4.2 Iridium and Platinum Electrodes ............................................................... 14
3 Experimental Methods ......................................................................................... 17
3.1 Method and Principle of Intentional Contamination ......................................... 17
3.2 Analytical and Electrical Measurements.......................................................... 20
3.2.1 Total Reflection X-Ray Fluorescence and Vapor Phase Decomposition-
Total Reflection X-Ray Fluorescence ................................................................ 20
3.2.2 Time of Flight-Secondary Ion Mass Spectroscopy.................................... 23
3.2.3 Electrolytic Metal Tracer .......................................................................... 26
3.2.4 Deep Level Transient Spectroscopy ........................................................ 29
3.2.5 Gate Oxide Integrity.................................................................................. 32
4 Properties of Barium, Strontium, Bismuth, Iridium, and Platinum Impurities in
Silicon ....................................................................................................................... 41
4.1 General Properties of Metals in Silicon ........................................................... 41
4.2 Desorption Properties of Contaminants on Silicon Surface............................. 43
4.2.1 Desorption Properties of Barium............................................................... 43
4.2.2 Desorption Properties of Strontium 46
4.2.3 Desorption Properties of Bismuth ............................................................. 48
4.2.4 Desorption Properties of Iridium 50
4.2.5 Desorption Properties of Platinum ............................................................ 53
4.3 Diffusion Properties of Contaminants in Silicon............................................... 57
4.3.1 Time of Flight-Secondary Ion Mass Spectroscopy Analysis of Barium,
Strontium, and Bismuth ..................................................................................... 57
4.3.2 Temperature Dependence of the Barium and Strontium Diffusion
Coefficient.......................................................................................................... 60
4.3.3 Secondary Ion Mass Spectroscopy Analysis of Iridium and Platinum....... 61
4.3.4 Study by Deep Level Transient Spectroscopy .......................................... 67
4.4 Diffusion of Contaminants in Poly-Silicon........................................................ 71
5 Electrical Characterization of Intentionally Contaminated Samples ..................... 77
5.1 Influence on the Minority Carrier Lifetime 77Contents ii
5.1.1 Barium, Strontium, and Bismuth Contaminated Wafers............................ 78
5.1.2 Iridium Contaminated Wafers ................................................................... 83
5.1.3 Platinum Contaminated Wafers ................................................................ 87
5.2 Design and Technology of Test Chip .............................................................. 90
5.2.1 LOCOS Isolation....................................................................................... 91
+ +5.2.2 N and P Implantation ............................................................................. 91
5.2.3 Gate Oxide Growth, Poly-Silicon Deposition, and Patterning ................... 92
5.2.4 Interlayer Dielectric and Planarization ...................................................... 93
5.2.5 Metallization.............................................................................................. 93
5.3 Leakage Current Measurement on Contaminated Diodes .............................. 95
5.3.1 Barium, Strontium, and Bismuth Contaminated Diodes............................ 97
5.3.2 Iridium Contaminated Diodes.................................................................. 100
5.3.3 Platinum Contaminated Diodes .............................................................. 103
5.3.4 Discussion of the Leakage Current Results............................................ 105
5.4 Gate-Oxide Integrity Evaluation..................................................................... 106
5.4.1 Results from E-Ramp ............................................................................. 106
5.4.2 Results from Constant Current Stress Charge to Breakdown................. 113
5.4.3 Discussion of the Results ....................................................................... 125
6 Summary and Outlook ....................................................................................... 132
6.1 Résumé of the Properties of the Contaminants............................................. 132
6.2 Résumé of the Impact of the Contaminants .................................................. 133
6.3 Future Work and General Conclusion ........................................................... 135
References......................................................................................................... 136
List of Symbols and Abbreviations......................................................................143 Abstract
In memory technology, new materials are being intensively investigated to overcome
the integration limits of conventional dielectrics for Giga-bit scale integration, or to be
able to produce new types of non-volatile low power memories such as FeRAM.
Perovskite type high dielectric constant films for use in Giga-bit scale memories or
layered perovskite films for use in non-volatile memories involve materials to
semi