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Information to Users INFORMATION TO USERS This manuscript has been reproduced from the microfilm master. UMI films the text directly from the original or copy submitted. Thus, some thesis and dissertation copies are in typewriter face, while others may be from any type of computer printer. The quality of this reproduction is dependent upon the quality of the copy submitted. Broken or indistinct print, colored or poor quality illustrations and photographs, print bleedthrough, substandard margins, and improper alignment can adversely affect reproduction. In the unlikely event that the author did not send UMI a complete manuscript and there are missing pages, these will be noted. Also, if unauthorized copyright material had to be removed, a note will indicate the deletion. Oversize materials (e.g., maps, drawings, charts) are reproduced by sectioning the original, beginning at the upper left-hand corner and continuing from left to right in equal sections with small overlaps. Each original is also photographed in one exposure and is included in reduced form at the back of the book. Photographs included in the original manuscript have been reproduced xerographically in this copy. Higher quality 6" x 9" black and white photographic prints are available for any photographs or illustrations appearing in this copy for an additional charge. Contact UMI directly to order. University Microfilms International A Bell & Howell Information Company 300 North Zeeb Road, Ann Arbor, Ml 48106-1346 USA 313/761-4700 800/521-0600 Order Number 9S16211 Laser diagnostics of atomic hydrogen and oxygen production in RF and microwave plasma discharges Preppemau, Bryan Lee, Ph.D. The Ohio State University, 1993 UMI 300 N. Zeeb Rd. Ann Arbor, MI 48106 LASER DIAGNOSTICS OF ATOMIC HYDROGEN AND OXYGEN PRODUCTION IN RF AND MICROWAVE PLASMA DISCHARGES DISSERTATION Presented in Partial Fulfillment of the Requirements for the Degree Doctor of Philosophy in the Graduate School of the Ohio State University By Bryan Lee Preppemau, B.A., B.S.E. ft ft ft * * The Ohio State University 1993 Dissertation Committee: Approved by T. Miller E. Herbst Adviser T. Gustafson Chemical Physics Program ACKNOWLEDGMENTS This dissertation reflects the culmination of many years of endeavor and I should express my appreciation to those who have contributed in many ways to enhance my own efforts while in Graduate School. In addition, I wish also to recognize the support and guidance of those I've have know professionally throughout the years and from my previous education. Therefore, I wish to sincerely thank all of those listed below as well as my parents and family and especially my wife, Mary Post, for their unending consideration and wisdom. The Ohio State University: Dr. Terry Miller Dr. Vish Subramaniam Dr. Suliman Dregia Dr. Harris Kagan Dr. Richard Kass Dr. Terry Gustafson Dr. Jim Dunlop Dr. David Dolson Chris Carter Angelika Tserepi Tim Cerny Ken Pearce AT&T Bell Laboratories Dr. Richard Gottscho Advanced Plasma Group. Wright-Patterson Air Force Base: Dr. Bish Ganguly Dr. Alan Garscadden Dr. Peter Bletzinger Dr. Charles Dejoseph Air Force Institute of Technology: Dr. Eric Jumper Dr. William Bailey Dr. Max Stafford Reed College: Dr. Nick Wheeler Dr. David Griffiths Dr. Ken Davis VITA April 18,1959 .......................................................Born - Aberdeen, Maryland 1981 ..................................................... B.A., Physics, Reed College Portland, Oregon 1982-1987 ......................................................Officer, United States Air Force 1984 ..............................................................B.S.E., Aeronautical Engineering Air Force Institute of Technology Wright-Patterson AFB, Ohio 1987-Present ..................................................... Graduate Research Assistant Chemical Physics Program The Ohio State University PUBLICATIONS Absolute H-Atom Concentration Profiles in Continuous and Pulsed RF Discharges, A. Tserepi, J. Dunlop, B. Preppemau, and T. Miller, J. Appl. Phys., 72 (7), 2638, 1992. The Effects of Surfaces on H-Atom Concentration in Pulsed and Continuous Discharges, A. Tserepi, J. Dunlop, B. Preppemau, and T. Miller, J. Vac. Sci. & Tech., 10 (4), 1188,1992. Nucleation and Growth of Diamond on Silicon using Hot Filament CVD, J. Rebello, D.Straub, V. Subramaniam, E.. Tan, S. Dregia, B. Preppemau, and T. Miller, Mat. and Manuf. Processes, 6, 501,1991. H-Atom Plasma Diagnostics: A Sensitive Probe of Temperature and Purity, J. Dunlop, A. Tserepi, B. Preppemau, T. Cerny, and T. Miller, Plasma Chem. and Plasma Process., 11 (4), 1991 hi Real-Time Monitoring of Low-Temperature Hydrogen Plasma Passivation of GaAs, R. Gottscho, B. Preppemau, S. Pearton, A. Emerson, and K. Giapis, J. Appl. Phys., 68 (2), 440,1990. Enhanced Atomic Hydrogen Concentration Measurements in Radio Frequency Discharges, B. Preppemau and T. Miller, J. Vac. Sci. Technol. A, 8 (3), 1673, 1990. Temporally Resolved Laser Diagnostic Measurements of Atomic Hydrogen Concentrations in RF Plasma Discharges, B. Preppemau, D. Dolson, R. Gottscho and T. Miller, Plasma Chem. and Plasma Process., 9 (2), 157, 1989. Rydberg State Stark Spectroscopic Measurement of Electric-Field Profile in a Glow Discharge, B. Ganguly, J. Shoemaker, B. Preppemau, and A. Garscadden, J. Appl. Phys., 61 ( 8 ), 2778,1987. Adaptations of a Wall-Catalytic Fluorine Recombination Model to Fluid- Dynamic Computations in an HF Laser Nozzle, E. Jumper, P. Wilkins, and B. Preppemau, J. AIAA, Apr 1987. Laser-Based Diagnostics of Reactive Plasmas, B. Preppemau and T. Miller, (Plenum Press, New York, 1993). FIELDS OF STUDY Major Field: Chemical Physics TABLE OF CONTENTS Page ACKNOWLEDGMENTS......................................................................................ii VITA.................................................................................................................iii UST OF TABLES.............................. vi UST OF FIGURES............... vii CHAPTER I. INTRODUCTION TO LASER DIAGNOSTICS FOR PLASMA PROCESSING 1 A. Scientific and Technological Significance of Plasmas ....................1 B. Technological Impact of CVD Diamond ...........................................4 C. Overview of Plasma Diagnostic Techniques ................................... 7 H. THE GEC REFERENCE CELL.......................................................................12 m. DIAMOND CHEMICAL VAPOR DEPOSITION CHEMISTRY........................ 21 IV. EXPERIMENTAL TECHNIQUES...................................................................34 A. Experiment Apparatus ....................................................................34 B. H-Atom and O-Atom Concentration Calibration Procedure ....... 44 C. Effects of Quenching Upon Concentration Measurements .........50 V. EXPERIMENTAL RESULTS FROM A GEC REFERENCE CELL...................... 85 VI. EXPERIMENTAL RESULTS FROM AN ASTEX DIAMOND REACTOR.......104 APPENDIX A: EXPERIMENTAL QUENCHING DATA......................................127 APPENDIX B: COMPUTER ACQUISITION AND ANALYSIS PROGRAMS.......135 BIBLIOGRAPHY..............................................................................................174 v UST OF TABLES Table Page 1. Comparison of Diamond and Silicon Electronic Properties ................ 5 2. Comparison of Measured and Calculated Fluorescence Lifetimes for Helium Quenching .................................................................................75 3. Comparison of Measured and Calculated Fluorescence Lifetimes for Argon Quenching .................................................................................. 79 4. Cross-Sections for Quenching of Hydrogen Atoms (n=3) ...................82 5. Computed Maximum H-Atom Densities in GEC Reference Cell 92 vi UST OF FIGURES Figure Page 1. The GEC Reference Cell ....................................................................13 2. C-H-0 Phase Diagram. Unshaded area is nominal diamond growth region ........................... .........................................................................25 3. Experiment Layout Schematic for H-Atom TALIF ..........................36 4. Experiment Layout Schematic for O-Atom TAUF ..........................40 5. Representative H-Atom TAUF Signal Trace .................................... 42 6 . Titration Assembly ........................................................................... 47 7. O-Atom TAUF Titration Curve. Data corresponds to a concentration of 5.98 x 1015 cm-3. Line is a linear regression extrapolation for determining the titration endpoint. X-intercept is 7.63 seem of NO2................................................................................... 49 8 . H-Atom TAUF by Photodissociation of C 2H2..................................52 9. Nonlinear Dependence of C 2H2 H-Atom TAUF Signal. Straight line represents a linear regression fit to the initial rise of the data 53 10. Inverse Quantum Yield Dependence on Pressure........................55 11. Radiative Lifetime of n=3 State from Photodissociated C 2H2 H- Atom TAUF............................................................................................ 58 12. Radiative Decay of n=3 Component Levels for 1 Torr Quenching by H2. Also shown is the Normalized Radiative Rate, R* .................. 63 13. Radiative Decay of n=3 Component Levels for 10 Torr Quenching by H2. Also shown is the Normalized Radiative Rate, R* ....................................................................................................64 14. Calculated Quenching Curves With and Without
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