Influence of reactive sputtering process parameters on the structure and properties of TiO2 thin films [Elektronische Ressource] / Azza El-Hamshary

Aamin

Sujets

• Physik

Informations

• Publié par: rheinisch-westfalischen_technischen_hochschule_-rwth-_aachen
• Publié le: 01 janvier 2011
• Nombre de lectures: 19
• Langue: English
• Poids de l'ouvrage: 8 Mo

Extrait

Influence of reactive sputtering process
parameters on the structure and properties of
TiO thin films 2



Von der Fakultät für Mathematik, Informatik und Naturwissenschaften
der Rheinisch-Westfälischen Technischen Hochschule Aachen
zur Erlangung des akademischen Grades einer
Doktorin der Naturwissenschaften genehmigte Dissertation



vorgelegt von

M.Sc. Azza Amin El-Hamshary
aus Kairo/ Ägypten


Berichter: Universitätsprofessor Dr. Matthias Wuttig
Universitätsprofessor Dr. Dieter Mergel

Tag der mündlichen Prüfung: 11.Juli 2011


Diese Dissertation ist auf den Internetseiten der Hochschulbibliothek
online verfügbar.





DEDICATION

I dedicate this Thesis to,,,

My Father,

My Mother,

All My Family,

Soul of 25 January revolution martyrs, and

My entire lovely persons in this world.


Contents
1. INTRODUCTION ...................................................................................................................... 1
2. TITANIUM DIOXIDE- PROPERTIES AND APPLICATIONS ...................................................... 5
2.1 APPLICATIONS AND PROPERTIES ................................................................................................. 5
2.2 CORRELATION: STRUCTURE AND DEPOSITION PARAMETERS .............................................................. 7
2.2.1 Growth of TiO thin films upon variation of oxygen flow.......................................................... 7 2
2.2.2 Film thickness parameter .................................................................................................. 9
2.2.3 Substrate temperature ..................................................................................................... 10
2.2.4 Energetic particles ......................................................................................................... 11
2.3 PHOTO-INDUCED PROPERTIES .................................................................................................. 16
2.3.1 Photoconductivity .......................................................................................................... 17
3. SPUTTER DEPOSITION AND FILM GROWTH ....................................................................... 22
3.1 SPUTTERING PROCESS ............................................................................................................ 22
3.1.1 Concept of sputtering...................................................................................................... 22
3.1.2 Principle of glow discharge for sputtering .......................................................................... 24
3.1.3 Magnetron Sputtering ..................................................................................................... 26
3.1.4 Reactive magnetron sputtering ......................................................................................... 27
3.1.5 Berg’s model (Theoretical modeling of reactive sputtering) .................................................... 30
3.1.6 High power Impulse magnetron sputtering .......................................................................... 32
3.2. MECHANISM OF FILM GROWTH ................................................................................................ 34
3.2.1. Nucleation ................................................................................................................... 35
3.2.2. Coalescence ................................................................................................................. 36
3.2.3. Advanced layer growth .................................................................................................. 37
3.3. INFLUENCE OF ENERGETIC PARTICLES ON THE FILM GROWTH DURING SPUTTERING ............................. 40
3.4. GENERATION OF STRESSES IN THIN FILMS .................................................................................. 42
3.4.1 Atomic peening model ..................................................................................................... 43
3.4.2 Momentum transfer model ............................................................................................... 44
3.4.3 Knock-on implantation and thermal spike (Davis model) ....................................................... 46
4. EXPERIMENTAL TECHNIQUES ............................................................................................ 50
4.1 SPUTTER DEPOSITION TECHNIQUES ........................................................................................... 50
4.2 ION BEAM ASSISTED SETUP ...................................................................................................... 51
4.3 FILMS PREPARATION .............................................................................................................. 53
4.4 ANALYSIS OF FILM STRUCTURE ................................................................................................ 53
4.4.1 GI-X-Ray diffraction ....................................................................................................... 53
4.4.2 Atomic Force Microscopy (AFM) ...................................................................................... 56
4.4.3 Transmission Electron Microscopy (TEM) .......................................................................... 57
4.5 OPTICAL PROPERTIES AND FILM THICKNESS ................................................................................ 59
4.5.1 Spectroscopic ellipsometry .............................................................................................. 59
4.5.2 Reflectance and transmittance .......................................................................................... 60
4.5.3 Modeling of the dielectric function .................................................................................... 61
4.6 IN-SITU STRESS MEASUREMENTS BY WAFER CURVATURE METHOD ................................................... 63
4.7 PHOTOCONDUCTIVITY ............................................................................................................ 64
5. THE INFLUENCE OF ENERGETIC PARTICLES ON THE STRUCTURE OF REACTIVELY
SPUTTERED TIO THIN FILMS ................................................................................................. 68 2
5.1 TARGET CHARACTERIZATION AND DEPOSITION CHARACTERISTICS ................................................... 68
5.2 ROLE OF ENERGETIC PARTICLES DURING FILM GROWTH ................................................................. 71
i
CONTENTS

5.3 CRYSTAL STRUCTURE AND SURFACE TOPOGRAPHY OF SPUTTERED TIO THIN FILMS ............................ 74 2
5.3.1 Prepared by ion- assisted reactive dcMS ............................................................................ 74
5.3.2 Influenced by racetrack geometry...................................................................................... 80
5.3.3 Deposited by dcMS under reduced oxygen ion bombardment .................................................. 88
5.3.4 Structure evolution in a HiPIMS process ............................................................................ 90
5.3.5 Thermal stability of films grown under intense ion bombardment ............................................ 96
5.4 MECHANICAL GROWTH STRESS ................................................................................................ 98
5.4.1 Dependence of film stress on the oxygen content in the process ............................................. 100
5.4.2 Influence of sputtering pressure on the film stress .............................................................. 102
5.4.3 Variation of the film stress with the discharge current ......................................................... 102
5.5. DISCUSSION ...................................................................................................................... 105
5.6. CONCLUSION ..................................................................................................................... 108
6. STRUCTURE ZONE MODEL FOR THE GROWTH OF REACTIVELY SPUTTERED TIO THIN 2
FILMS ..................................................................................................................................... 110
6.1 INTRODUCTION ................................................................................................................... 110
6.2 INFLUENCE OF OXYGEN PARTIAL PRESSURE ON THE STRUCTURE .................................................... 111
6.3 THE ROLE OF FILM THICKNESS ON THE STRUCTURE FORMATION .................................................... 114
6.4 HOMOGENEITY OF THE FILM STRUCTURE (SMALL ANGLE ROCKING CURVE) .................................... 122
6.5 MODELING OF THE SMALL ANGLE ROCKING CURVE SCANS ........................................................... 124
6.6 MICROSTRUCTURE .............................................................................................................. 131
6.7 INFLUENCE OF BUFFER LAYER AND HEATING ON THE STRUCTURE FORMATION .................................. 135
6.8 STRUCTURE ZONE MODEL ..................................................................................................... 139
6.9 DISCUSSION .........