Study of nano roughness for silica on silicon technology by Scanning Electron Microscopy and light scattering

Alexis Bony

Description

Niveau: Supérieur, Doctorat, Bac+8
THESIS Study of nano-roughness for silica-on-silicon technology by Scanning Electron Microscopy and light scattering. to obtain the DOCTORATE DEGREE in THE LOUIS PASTEUR UNIVERSITY OF STRASBOURG Speciality: Engineering Sciences - Photonics by Alexis BONY Host laboratory: Alcatel SEL AG, Research and Innovation Center in Photonics – Passive Components Division, Stuttgart, Germany. University laboratory: Laboratoire des Systèmes Photoniques – EA2312, Illkirch, France. Defended the 6th of December 2004 before the doctoral committee: MEYRUEIS Patrick Professor – Louis Pasteur University, Strasbourg, France. MONTGOMERY Paul C. Researcher – CNRS-PHASE, Strasbourg, France. GORECKI Christophe Research Director – CNRS-LOPMD, Besançon, France. O'DONNELL Kevin A. Professor – CICESE, Enseñada, Mexico. TAKAKURA Yoshitate Researcher – Louis Pasteur University, Strasbourg, France. SATZKE Klaus Researcher – Alcatel SEL AG, Stuttgart, Germany

• roughness measurement


• angle-resolved light


• yoshitate takakura


• digital correlation


• experimental aspects


• scattering


• measurement

Sujets

• Górecki
• Research
• Professor
• Roughness
• Montgomery
• Researcher
• Pasteur
• Bilger
• Louis Pasteur University

Informations

• Publié par: profil-zyak-2012
• Nombre de lectures: 21
• Langue: English
• Poids de l'ouvrage: 5 Mo

Extrait

THESIS

Study of nano-roughness for silica-on-silicon technology by
Scanning Electron Microscopy and light scattering.

to obtain the

DOCTORATE DEGREE
niTHE LOUIS PASTEUR UNIVERSITY OF STRASBOURG
Speciality: Engineering Sciences - Photonics

Host laboratory: Alcatel SEL AG, Research and Innovation Center in Photonics – Passive
Components Division, Stuttgart, Germany.
University laboratory: Laboratoire des Systèmes Photoniques – EA2312, Illkirch, France.
Defended the 6th of December 2004 before the doctoral committee:
MEYRUEIS Patrick Professor – Louis Pasteur University, Strasbourg, France.
MONTGOMERY Paul C. Researcher – CNRS-PHASE, Strasbourg, France.
GORECKI Christophe Research Director – CNRS-LOPMD, Besançon, France.
O'DONNELL Kevin A. Professor – CICESE, Enseñada, Mexico.
TAKAKURA Yoshitate Researcher – Louis Pasteur University, Strasbourg, France.
SATZKE Klaus Researcher – Alcatel SEL AG, Stuttgart, Germany

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Acknowledgements
I owe thanks to many people who helped me at different stages of this Ph.D.
First of all, I am indebted to Yoshitate Takakura for his permanent availability, assistance, and
patience, despite the null administrative advantage he could receive from this task. Yoshi's
usual approach, which consists in criticizing every idea, result, measurement, or data,
although sometimes driving to despair, proved to be an indispensable mentor during this
work.
Organizing a Ph.D. work between a company and a university requires time and persistence,
and I am glad to thank Dr. Kurt Lösch, Dr. Armin Baumgärtner and Dr. Klaus Satzke, from
Alcatel SEL AG, and Prof. Meyrueis, from the Photonic Systems Laboratory of Louis Pasteur
University for the faith they granted me.
Constituting a jury is not an easy task for a Ph.D. student, and I would like to thank Dr. Paul
Montgomery, Dr. Christophe Gorecki, and Prof. Kevin O'Donnell for having accepted
evaluating this work with enthusiasm.
I had initially planned to cite all the people who helped me in many ways during this Ph.D.,
and started writing a list in order to be sure not to forget anybody. Unfortunately, the size of
this list would generate a new paragraph to be fulfilled. However, I would particularly like to
acknowledge André Heid, who trained me using the SEM, and was always available to
answer my numerous questions, and André Bilger, who prepared the mechanical pieces for
the light scattering experiment.
Carrying out a Ph.D. brings its dose of stress, and I would like to thank the persons who
shared my life during this period for their patience and support.
As a Ph.D. is often considered as the end of one's education, I would like to thank my parents
for their convinced and unalterable encouragement. Their first priority has always remained
the achievement of my aspirations or wishes (even at the expanse of financial reason), and
these few lines are only a poor compensation in comparison with the invaluable heritage they
gave me.

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Table of contents

I Introduction......................................................................................................................12
I.1 What is roughness....................................................................................................12
I.1.1 Defining roughness..............................................................................................12
I.1.2 Roughness and light scattering.............................................................................15
I.2 Measuring roughness................................................................................................16
I.2.1 Instruments for surface roughness measurement.................................................16
I.2.2 Comparison between instruments........................................................................28
I.3 Silica-on-silicon optical waveguides........................................................................29
I.3.1 Materials and fabrication......................................................................................29
I.3.2 Applications.........................................................................................................30
I.3.3 Roughness formation............................................................................................30
II SEM-based waveguide sidewall roughness measurement...............................................32
II.1 State of the art of available techniques for sidewall roughness measurement.........32
II.2 Visual inspection and Line-Edge Roughness measurement....................................35
II.2.1 Sidewall quality assessment via visual inspection...........................................36
II.2.2 Line-Edge Roughness measurement................................................................38
II.3 Stereoscopic approach..............................................................................................41
II.3.1 Theoretical description of the procedure..........................................................41
II.3.2 Practical implementation..................................................................................45
II.3.3 Results..............................................................................................................48
II.3.4 Conclusion on stereoscopic approach..............................................................51
II.4 Shape-from-shading approach..................................................................................52
II.4.1 Algorithm implementation...............................................................................52
II.4.2 Profile reconstruction.......................................................................................53
II.4.3 Calibration issues.............................................................................................55
II.4.4 Roughness distinction and resolution...............................................................56
II.4.5 Issues for practical implementation..................................................................57
II.4.6 Extension to deep silica etching.......................................................................65
II.5 Comparison of stereoscopy, SFS, and competing techniques..................................67
II.5.1 Comparison of stereoscopy and shape-from-shading techniques....................67
II.5.2 Comparison with competing techniques..........................................................68
II.6 Ideas for further developments.................................................................................69
III Light scattering from silica-on-silicon wafers.............................................................70
III.1 Physical description of the studied phenomena.......................................................70
III.1.1 Physical origin of speckle................................................................................70
III.1.2 Speckle correlations.........................................................................................72
III.1.3 Angle-resolved light scattering........................................................................74
III.2 Experimental aspects................................................................................................75
III.2.1 Experimental set-up..........................................................................................75
III.2.2 Description of the samples...............................................................................78
III.3 Angle-resolved light scattering................................................................................82
III.3.1 Diffused fringes................................................................................................82
III.3.2 Thickness retrieval...........................................................................................86
III.3.3 Grazing angle approach....................................................................................89
III.3.4 Retrodiffusion approach...................................................................................91
III.4 Speckle correlations.................................................................................................94
III.4.1 Principles of speckle pattern recording and of correlation evaluation.............94

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III.4.2 Experimental angle-resolved speckle correlations...........................................95
III.4.3 Alternative way of evaluating speckle correlation (via digital correlation
calculation in Fourier plane)............................................................................................97
)01(III.4.4
C
correlation condition..............................................................................103
III.5 Conclusions on speckle and light scattering studies..............................................105
Bibliography...............................................