Indium Nitride Surface Structure, Desorption Kinetics and

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Indium Nitride Surface Structure, Desorption Kinetics and

Transcript Of Indium Nitride Surface Structure, Desorption Kinetics and

Georgia State University
ScholarWorks @ Georgia State University

Physics and Astronomy Dissertations

Department of Physics and Astronomy

Summer 8-12-2013
Indium Nitride Surface Structure, Desorption Kinetics and Thermal Stability
Ananta R. Acharya

Follow this and additional works at: https://scholarworks.gsu.edu/phy_astr_diss
Recommended Citation Acharya, Ananta R., "Indium Nitride Surface Structure, Desorption Kinetics and Thermal Stability." Dissertation, Georgia State University, 2013. doi: https://doi.org/10.57709/4266248
This Dissertation is brought to you for free and open access by the Department of Physics and Astronomy at ScholarWorks @ Georgia State University. It has been accepted for inclusion in Physics and Astronomy Dissertations by an authorized administrator of ScholarWorks @ Georgia State University. For more information, please contact [email protected]

INDIUM NITRIDE SURFACE STRUCTURE, DESORPTION KINETICS AND THERMAL STABILITY
by
ANANTA ACHARYA
Under the Direction of Dr. Brian D. Thoms
ABSTRACT Unique physical properties such as small effective mass, high electron drift velocities, high electron mobility and small band gap energy make InN a candidate for applications in highspeed microelectronic and optoelectronic devices. The aim of this research is to understand the surface properties, desorption kinetics and thermal stability of InN epilayers that affect the growth processes and determine film quality as well as device performance and life time. We have investigated the structural properties, the surface desorption kinetics, and the thermal stability using Auger electron spectroscopy (AES), x-ray diffraction (XRD), Raman spectroscopy, atomic force microscopy (AFM), high resolution electron energy loss spectroscopy

(HREELS), and temperature programmed desorption (TPD). Investigations on high pressure chemical vapor deposition (HPCVD)-grown InN samples revealed the presence of tilted crystallites, which were attributed to high group V/III flux ratio and lattice mismatch. A study of the thermal stability of HPCVD-grown InN epilayers revealed that the activation energy for nitrogen desorption was 1.6±0.2 eV, independent of the group V/III flux ratio. Initial investigations on the ternary alloy In0.96Ga0.04N showed single-phase, N-polar epilayers using XRD and HREELS, while a thermal desorption study revealed an activation energy for nitrogen desorption of 1.14 ± 0.06 eV.
HREELS investigations of atomic layer epitaxy (ALE)-grown InN revealed vibrational modes assigned to N-N vibrations. The atomic hydrogen cleaned InN surface also exhibited modes assigned to surface N-H without showing In-H species, which indicated N-polar InN. Complete desorption of hydrogen from the InN surface was best described by the first-order desorption kinetics with an activation energy of 0.88 ± 0.06 eV and pre-exponential factor of (1.5 ± 0.5) ×105 s-1.
Overall, we have used a number of techniques to characterize the structure, surface bonding configuration, thermal stability and hydrogen desorption kinetics of InN and In0.96Ga0.04N epilayers grown by HPCVD and ALE. High group V/III precursors ratio and lattice mismatch have a crucial influence on the film orientation. The effects of hydrogen on the decomposition add to the wide variation in the activation energy of nitrogen desorption. Presence of surface defects lowers the activation energy for hydrogen desorption from the surface.

INDEX WORDS:

Indium nitride, surface structure, high resolution electron energy loss spectroscopy, tilted crystallites, polarity, thermal desorption, activation energy

INDIUM NITRIDE SURFACE STRUCTURE, DESORPTION KINETICS AND THERMAL STABILITY
by
ANANTA ACHARYA
A Dissertation Submitted in Partial Fulfillment of the Requirements for the Degree of Doctor of Philosophy
in the College of Arts and Sciences Georgia State University 2013

Copyright by Ananta Raj Acharya
2013

INDIUM NITRIDE SURFACE STRUCTURE, DESORPTION KINETICS AND THERMAL STABILITY
by ANANTA ACHARYA

Electronic Version Approved:
Office of Graduate Studies College of Arts and Sciences Georgia State University August 2013

Committee Chair: Brian D. Thoms
Committee: Nikolaus Dietz Vadyam Apalkov Douglas Gies Mukesh Dhamala

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Dedicated to my parents, lovely daughter Monica, son Asmin And
wife Muna

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ACKNOWLEDGEMENTS
I would like to express my deepest gratitude and sincere thanks to a number of people who inspired and supported me towards my Ph.D. studies and helped me complete it. First of all, I would like to thank my advisor Dr. Brian D. Thoms for his continuous guidance and supervision that made this work possible. He was always ready to explain and help me when I had problems and confusion about conducting experiments, maintaining devices, analyzing the data and correcting my writing. I found myself extremely fortunate to work with an advisor like Dr. Thoms.
Next, I would like to express my sincere thanks to Prof. Nikolaus Dietz, not only for providing the InN and InGaN samples but also for reviewing the contents of my papers and his constructive advice from his expertise in nitride semiconductors. I am grateful to my previous lab mate, Dr. Rudra P. Bhatta, who helped me in handling and maintaining UHV equipment, and running the experiments. I definitely express my thanks to Dr. Max Buegler and Sampath Gamage from Dr. Dietz’s group who worked late nights frequently to produce good quality InN and InGaN samples. Also, I am grateful to other members in Dr. Dietz’s research group, Dr. Ramazan Atalay, Indika Kankanamge, Rasanga Samaraweera, and Kasuni Nanayakkara for their valuable suggestions and conversations related to research and daily life. I would like to acknowledge Charles Hopper, Peter Walker and others in the instrument shop of Physics and Astronomy at GSU for construction and repairing parts of UHV system. I want to gratefully acknowledge former head of the department Dr. Richard Miller, former graduate director Dr. Unil Perera, present department chair Dr. Michael Crenshaw, and graduate director Dr. Xiaochun

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He for helping me in every aspect and providing me with useful guidance in order to complete my graduate study.
I would like to thank to my parents, my daughter Monica, son Asmin and my brothers for their unconditional infinite love and support throughout my endeavor. I am forever indebted to them for their constant support which made me what I am today. Finally, I would like to express my special thanks to my lovely wife, Muna, for her all love, invaluable dedication, sacrifice and companionship. For me, she has always been a source of inspiration to work hard and succeed. Without her presence, it would have been much more difficult to finish this dissertation. Being the closest person to me, she had to suffer through a number of ups and downs during my Ph.D. studies. However, she never stopped bringing happiness and joy in my life which always encouraged me to work harder and make my studies successful. Thank you so much for everything you have done for me.

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TABLE OF CONTENTS ACKNOWELEDGEMENTS……………………………………………………………v LIST OF TABLES............................................................................................................xi LIST OF FIGURES ........................................................................................................ xii LIST OF ABBREVIATIONS........................................................................................xiv 1 INTRODUCTION AND MOTIVATION ………………………………………....1
1.1 Introduction..........................................................................................................1 1.2 Motivation ............................................................................................................ 3 2 GROUP III-NITRIDE SEMICONDUCTORS ........................................................ 5 2.1 Introduction ......................................................................................................... 5 2.2 Properties ............................................................................................................. 6 2.3 InN ...................................................................................................................... 10
2.3.1 Introduction ................................................................................................... 10 2.3.2 Growth............................................................................................................ 12 2.3.2.1 Metal organic chemical vapor deposition ................................................... 13 2.3.2.2 Molecular beam epitaxy............................................................................... 15 2.3.2.3 High pressure chemical vapor deposition ................................................... 17 2.3.2.4 Hydride vapor phase epitaxy ....................................................................... 18 2.3.2.5 Atomic layer deposition ............................................................................... 19 2.3.3 Structural properties.......................................................................................21 2.3.4 Electrical properties....................................................................................... 22 2.3.5 Optical properties........................................................................................... 24 2.3.6 Polarity ........................................................................................................... 25
Desorption KineticsStabilityActivation EnergyDissertationPhysics