Generation of pure iron nanostructures via electron-beam induced deposition in UHV [Elektronische Ressource] = Erzeugung von reinen Eisen-Nanostrukturen mittels elektronenstrahlinduzierter Abscheidung im UHV / vorgelegt von Thomas Lukasczyk

Generation of pure iron nanostructures via
electron-beam induced deposition in UHV
________________________________
Erzeugung von reinen Eisen-Nanostrukturen mittels
elektronenstrahlinduzierter Abscheidung im UHV
¯ ¯ ¯ ¯ ¯ ¯ ¯ ¯ ¯ ¯ ¯ ¯ ¯ ¯ ¯ ¯ ¯ ¯ ¯ ¯ ¯ ¯ ¯ ¯ ¯ ¯ ¯ ¯ ¯ ¯ ¯ ¯

Der Naturwissenschaftlichen Fakultät der
Friedrich-Alexander-Universität Erlangen-Nürnberg


zur Erlangung des Doktorgrades Dr. rer. nat.

vorgelegt von
Thomas Lukasczyk
aus Erlangen





















Als Dissertation genehmigt
durch die Naturwissenschaftliche Fakultät
der Friedrich-Alexander-Universität Erlangen-Nürnberg

Tag der mündlichen Prüfung: 7.5.2010

Vorsitzende/r der Promotionskommission: Prof. Dr. Bänsch
Erstberichterstatter/in: Prof. Dr. Steinrück
Zweitberichterstatter/in: Prof. Dr. Diwald

Table of contents
List of abbreviations ........................................................................... IV
1 Introduction.........................................................................................1
2 Fundamentals and techniques.............................................................5
2.1 Scanning electron microscopy (SEM)......................................................... 5
2.2 Auger electron spectroscopy (AES) .......................................................... 12
2.3 Scanning Auger electron microscopy (SAM) and Auger line scans......... 16
2.4 Scanning tunneling microscopy (STM)..................................................... 18
2.5 Quadrupole mass spectrometry (QMS) ..................................................... 19
2.6 Low energy electron diffraction (LEED) .................................................. 20
2.7 Electron-beam induced deposition (EBID) ............................................... 21
2.8 The precursor iron pentacarbonyl.............................................................. 32
3 Experimental setup ...........................................................................37
3.1 Vacuum system.......................................................................................... 37
3.1.1 Preparation chamber and fast entry lock chamber...................................................42
3.1.2 Analysis chamber.....................................................................................................46
3.1.3 Gas dosage system ...................................................................................................53
3.1.4 Gas Purification and Monitoring (GPM) chamber ..................................................56
3.2 Lithographic attachment ............................................................................ 59
3.3 Applied materials....................................................................................... 61
3.4 Experimental details and data processing.................................................. 63
4 Testing the Instrument: first EBID experiments ..............................77
4.1 Introduction................................................................................................ 77
4.2 Electron-beam lithography with PMMA................................................... 77
4.2.1 Basic principles of lithography with resist samples.................................................78
4.2.2 Results and discussion .............................................................................................82
4.3 EBID of carbonaceous structures .............................................................. 85
4.3.1 Characterization of the precursor.............................................................................85
4.3.2 Results and discussion .............................................................................................86
4.4 Summary and conclusions ......................................................................... 96
I
5 Iron pentacarbonyl on Rh(110) ........................................................99
5.1 Introduction................................................................................................99
5.2 The Rh(110) surface ................................................................................100
5.3 Preparation of Rh(110) in an UHV-SEM ................................................104
5.4 Visualizing reduction fronts on Rh(110) .................................................109
5.5 Influence of additional gas dosage...........................................................118
5.6 Surface quality determines the selectivity of EBID ................................124
5.6.1 Iron deposition on different sample states.............................................................125
5.6.2 Reduction of the autocatalytic behavior via a thin titanium layer.........................133
5.6.3. Summary...............................................................................................................140
5.7 Effect of the electron dose on the EBID process.....................................142
5.8 Thermal stability of iron structures..........................................................148
5.9 Selective oxidation of the iron structures ................................................154
5.10 Summary and conclusions .....................................................................157
6 Iron pentacarbonyl on silicon single crystal surfaces ....................161
6.1 Introduction..............................................................................................161
6.2 The substrates: Si(111) and Si(100) ........................................................162
6.3 Influence of the beam energy on the electron exit area...........................166
6.4 Material parameters in EBID with Fe(CO) on silicon ...........................170 5
6.4.1 Deposition of iron on Si(100) at room temperature ..............................................171
6.4.2 Influence of the precursor gas purity.....................................................................179
6.4.3 Deposition under clean conditions at 200 K..........................................................186
6.4.4 EBID with Fe(CO) on Si(111) .............................................................................193 5
6.5 Influence of the electron dose on the iron cluster density.......................196
6.6 Thermal stability of iron clusters on silicon ............................................204
6.7 Application: carbon nanotube growth on iron deposits...........................211
6.8 Summary and conclusions .......................................................................220
7 Summary.........................................................................................223
8 Zusammenfassung ..........................................................................227
9 Appendixes .....................................................................................231
9.1 Appendix to Chapter 3.............................................................................231
II
9.1.1 Electron filament setup in the preparation chamber ..............................................231
9.1.2 Characteristics of the different sample holder setups ............................................232
9.1.3 Scheme of the preparation chamber with port designation....................................234
9.1.4 Modification of the preparation chamber manipulator ..........................................236
9.1.5 Scheme of the analysis chamber with port designation.........................................239
9.1.6 Gas doser design ....................................................................................................242
9.1.7 Precursor storage device ........................................................................................243
9.1.8 Images of GPM-chamber.......................................................................................243
9.1.9 Manipulator positions in the preparation chamber ................................................244
9.1.10 Experimental parameters .....................................................................................245
9.1.11 Reference values for carbon and oxygen contaminations....................................247
9.2 Appendix to Chapter 5............................................................................. 249
9.2.1 Auger line scans on Sample III and Sample III-Ti ................................................249
9.3 List of applied data .................................................................................. 251
References..........................................................................................255

III
List of abbreviations
AE Auger electron
AES Auger Electron Spectroscopy
AFM Atomic Force Microscopy
BSE Backscattered electron
CCM Constant Current Mode
CEM Channel Electron Multiplier
CHM Constant Height Mode
CMA Cylindrical Mirror Analyzer
CNT Carbon Nanotube
CVD Chemical Vapor Deposition
DD D