Dr. Demetre J. Economou
John and Rebecca Moores Professor
Associate Chairman of Chemical and Biomolecular Engineering
Director, Plasma Processing Laboratory

Dept. of Chemical and Biomolecular Engineering
S222 Engineering Building 1
University of Houston
4800 Calhoun Ave.
Houston, TX 77204-4004
Office Location: S239
Telephone: (713) 743-4320
Fax: (713) 743-4323
E-mail: economou "at-sign" uh "dot" edu

EDUCATION

- Diploma, Chemical Engineering, National Technical University of Athens
- Ph.D., Chemical Engineering, University of Illinois at Urbana-Champaign (1986)

RESEARCH INTERESTS

Dr. Economou’s research focuses on plasma science and technology as applied to etching and deposition of thin solid films for microelectronic device fabrication, nanotechnology, and surface modification of materials (e.g., biomaterials). A combined modeling-simulation-experimental program is underway to develop mathematical models of plasma processes based on fundamental principles of transport phenomena, reaction kinetics and electromagnetic field distribution. Experimentally validated models are used to aid in optimization and control of existing processes or the design of new ones. Optimal design of experiments is also of interest. The projects described below are in collaboration with V. M. Donnelly.

›Plasma Modeling and Plasma Diagnostics
Continuum and particle (Particle-in-Cell, Monte Carlo) simulations are used to understand plasma flow in complex reactor geometries. Plasma “molding” over complex surface topography is studied, especially the energy and angular distribution of ions bombarding features with length scales of the order of the plasma sheath. Mathematical models are complemented with experimental measurements with emphasis on real-time non-intrusive spatially-resolved optical diagnostics, as well as ion flux, energy and angular distribution measurements.

Figure 1. Power deposition profile in an inductively coupled plasma reactor of axisymmetric (r,z) geometry. Radio frequency (RF) current through the "stovetop" coil powers the plasma. Such reactors are used for microelectronic device fabrication.

› Plasma Molding over Surface Topography
Particle-in-Cell with Monte Carlo collisions (PIC-MC) as well as fluid simulations are developed to study plasma “molding” over surface topography. The plasma-sheath meniscus over features (steps, trenches, holes) that are comparable to or larger than the sheath thickness is found self-consistently. Ion flow and energy and angular distributions of ions and energetic neutrals along the surface are computed and compared with experimental data. Applications include microelectromechanical systems (MEMS) fabrication, plasma extraction through grids, plasma thrusters, and neutral beam sources.

Figure 2. Plasma molding over a trench. The width and depth of the trench are D and H, respectively. When the sheath thickness Lsh is much smaller than D (case a), the plasma-sheath interface conforms faithfully to the surface topography. In the other extreme (Lsh >> D), the plasma-sheath interface is essentially planar. Case b (Lsh ~ D) is an intermediate situation between the two limiting cases, where the plasma-sheath interface gently bends over the trench.

A particle-in-cell simulation of beam extraction through a hole in contact with plasma was developed. Particular emphasis was placed on plasma molding over the hole, ion neutralization in high aspect ratio holes, and the energy and angular distributions of the residual ions and fast neutrals in the beam downstream of the hole. When the sheath thickness is much smaller than the diameter of the hole, plasma molding is severe, and the resulting ion and neutral beams are highly divergent. When the sheath thickness is much larger than the hole diameter, plasma molding is weak, and collimated beams may be extracted. The angular distribution of fast neutrals peaks off axis, less so for smaller diameter and deep holes. Larger diameter and shallow holes (more plasma molding) yield narrower ion energy distributions. The fast neutral energy distribution is predicted to be similar to that of ions, but it is shifted to lower energies. (click here for images)

›Nanopantography
This project deals with the fabrication of orderly arrays of nanofeatures (few nm length scale) with pre-defined shapes and patterns over large areas (10s of cm2). These can find application in growth of orderly arrays of singe wall carbon nanotubes, nanoelectronics, and nanocatalysis. Simulations of ion extraction from a plasma and ion beam focusing on the wafer to form nanofeatures by etching or deposition are used to guide experimentation.

›Micro-discharge Plasma Reactors
Miniaturized (~ 100s of microns) high pressure (~ 1 atm) micro-discharges are investigated for chemical microreactor, sensor and microelectromechanical systems (MEMS) applications. Spatially resolved (~5 micron resolution) diagnostics and modeling aid in understanding micro-discharge operation to facilitate applications of these micro-reactors. Optical emission spectroscopy measurements were performed for added trace probe gases in an atmospheric pressure direct current (DC) helium microplasma. Spatially resolved measurements (resolution ~ 6 mm) were taken across a 200 mm slot-type discharge. Gas temperature profiles were determined from N2 emission rotational spectroscopy. Stark splitting of the hydrogen Balmer-b line was used to investigate the electric field distribution in the cathode sheath region. Electron densities were evaluated from the analysis of the spectral line broadenings of Hb emission. The gas temperature was between 350 and 550 K, peaking nearer the cathode and increasing with power. The electron density in the bulk plasma was in the range 3-8 x 1013 cm-3. The electric field peaked at the cathode (~60 kV/cm) and decayed to small values over a distance of ~ 50 µm (sheath edge) from the cathode.  These experimental data were in generally good agreement with a self-consistent one-dimensional model of the discharge. The effect of gas flow on gas temperature was also studied. The gas temperature of an argon microdischarge decreased with increasing gas flow due to convective removal of heat. Convective heat loses were found not to be as important in helium microdischarges, due to the much higher thermal conductivity of the helium gas. Thus, heat losses were dominated by conductive transport in helium and by convective transport in argon. Experimental data of the peak gas temperature were in reasonable agreement with the simulation. The gas temperature peaked off axis near the cathode as ions accelerated in the cathode sheath deposit part of their energy in frequent collisions with the neutral gas. (click here for images)

›Processing with Energetic Neutral Beams
As device dimensions continue to shrink, charging damage due to ions and electrons bombarding the surface of devices during plasma processing has become a serious concern. We are investigating sources of energetic (100s of eV), high flux, collimated neutral beams (immune to charging problems) for anisotropic etching and deposition of thin films. Ions are extracted from a plasma and are neutralized through a grid with high aspect ratio holes. The efficiency of neutralization and neutral beam characterization (flux, energy distribution) are of particular interest.

Figure 3. Schematic of an energetic (100s of eV) neutral beam source (left) and SEM picture of quarter-micron wide features (right) etched with this source in polymer using an O-atom beam. Neutral beam sources can mitigate charging effects that can cause serious problems in advanced microelectronics fabrication.

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HONORS & ACTIVITIES

-2003: Fellow, American Vacuum Society
-2003: Outstanding Teaching Award, Cullen College of Engineering, University of Houston
-2002: Sigma Xi Faculty Research Award
-Guest Editor: IEEE Trans. Plasma Science, Special Issues, August 1995, October 1999, August     2003 and October 2007
-Guest Editor: Thin Solid Films, Special Issues, 2000, 2007
-1998-present: International Editorial Board, Materials Science in Semiconductor Processing
-1999: Senior Faculty Research Excellence Award, College of Engineering, University of Houston
-1996-Present: John and Rebecca Moores Professor
-1995: Excellence in Research and Scholarship Award, University of Houston
-1992: Best Young Author Paper Award of the Journal of Electrochemical Society
-1991: Young Faculty Research Excellence Award, Cullen College of Engineering,
     University of Houston

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SELECTED PUBLICATIONS

Refereed Publications in Archival Journals and Books

119. D. Economou, “Fundamentals and Applications of Ion-Ion Plasmas,” Appl. Surf. Science, 253, 6672-6680 (2007).

118. A. Ranjan, C. Helmbrecht, V. M. Donnelly, D. J. Economou, and G. Franz, “Effect of Surface Roughness on the Energy Distribution of Fast Neutrals and Residual Ions Extracted from a Neutral Beam Source,” J. Vac. Sci. Technol. B., 25, 258-263 (2007).
 
117. L. Xu, N. Sadeghi, V. M. Donnelly, and D. J. Economou, “Nickel Atom and Ion Density in an Inductively Coupled Plasma with an Internal Coil,” J. Appl. Phys., 101, 013304 (2007).
 
116. S. Belostotskyi, Q. Wang, V. M. Donnelly, D. J. Economou, and N. Sadeghi, “Three Dimensional Gas Temperature Measurements in Atmospheric Pressure Microdischarges Using Raman Scattering,” Appl. Phys. Lett., 89, 251503 (2007).
 
115. S. K. Nam, D. J. Economou, and V. M. Donnelly, “Particle-in-Cell Simulation of Ion Beam Extraction from a Pulsed Plasma Through a Grid,” Plasma Sources Sci. Technol., 16, 90-96 (2007).
 
114. S. K. Nam, D. J. Economou, and V. M. Donnelly, “Particle-in-Cell Simulation of Beam Extraction Through a Hole in Contact with Plasma,” J. Phys. D: Appl. Phys., 39, 3994-4000 (2006).
 
113. A. Ranjan, V. M. Donnelly, and D. J. Economou, “Energy Distribution and Flux of fast Neutrals and Residual Ions Extracted from a neutral beam Source,” J. Vac Sci. Technol. A 24, 1839-1846 (2006).
 
112. O Polomarov, C. Theodosiou, I. Kaganovich, B. Ramamurthi, and D. J. Economou, “Self-Consistent Modeling of Non-Local Inductively Coupled Plasmas,” IEEE Trans. Plasma Science, 34, 767-785 (2006).
 
111. Q. Wang, D. J. Economou, and V. M. Donnelly, “Simulation of Direct Current Micro-Plasma Discharge in Helium at Atmospheric Pressure,” J. Appl. Phys., 100, 023301 (2006).

110. L. Xu; S. C. Vemula; M. Jain, S. K. Nam; V. M. Donnelly; D. J. Economou; and P. Ruchhoeft, “Nanopantography: A New Method for Massively Parallel Nanopatterning over Large Areas,”  Nano Lett.; 5; 2563-2568 (2005).

109. S.G. Belostotsky, D.J. Economou, D.V. Lopaev, and T.V. Rakhimova, “Negative Ion Destruction by O(3P) Atoms and O2(a1∆g) Molecules in an Oxygen Plasma,” Plasma Sources Science and Technology, 14, 532-542 (2005).

108. L. Xu, D. J. Economou, V. M. Donnelly and P. Ruchhoeft, “Extraction of a Nearly Monoenergetic Ion Beam from a Pulsed Plasma,” Appl. Phys. Lett., 87, 041502 (2005).

107. O Polomarov, C. Theodosiou, I. Kaganovich, B. Ramamurthi, and D. J. Economou, “Effectiveness of electron-cyclotron and transmission resonance heating in inductively coupled plasmas,” Phys. Plasmas, 12, 104505 (2005).

106. Q. Wang, I. Koleva, V. M. Donnelly, and D. J. Economou, “Spatially Resolved Diagnostics of a Direct Current Atmospheric Pressure Helium Micro-plasma,” J. Phys. D: Appl. Phys., 38, 1690-1697 (2005).

105. S. Nam, V. M. Donnelly and D. J. Economou, “Particle-in-cell simulation of ion flow through a hole in contact with plasma,” IEEE Trans. Plasma Sci., 33, 232 (2005).

104. D. Economou, “Electronegative Plasma Reactor Engineering,” in Gaseous Dielectrics X,” edited by L. Christophorou, J. Olthoff, and P. Vassiliou, p. 157-166, Springer (2004).

103. S. K. Nam and D. J. Economou, “Two-Dimensional Simulation of a Miniaturized Inductively Coupled Plasma,” J. Appl. Phys., 95, 2272-2277 (2004).

102. D. Kim and D. J. Economou, “Simulation of a Two-Dimensional Sheath over a Flat Insulator-Conductor Interface on a RF Biased Electrode in a High Density Plasma,” J. Appl. Phys., 95, 3311-3318 (2004).

101. D. Kim and D. J. Economou, “Plasma Molding over Deep Trenches and the Resulting Ion and Energetic Neutral Distributions,” J. Vac. Sci. Technol. B 21, 1248-1253 (2003).

100. D. Kim and D. J. Economou, “Simulation of Plasma Molding over a Ring on a Flat Surface,” J. Appl. Phys., 94, 3740-3747 (2003).

99. D. Kim and D. J. Economou, “Simulation of a Two-Dimensional Sheath over a Flat Wall with an Insulator-Conductor Interface Exposed to a High Density Plasma,” J. Appl. Phys., 94, 2852-2857 (2003).

98. B. Ramamurthi, D. J. Economou, and I. Kaganovich, “Effect of Electron Energy Distribution Function on Power Deposition and Plasma Density in an Inductively Coupled Discharge at Very Low Pressures,” Plasma Sources Sci. Technol. 12, 302-312 (2003).

97. B. Ramamurthi, D. J. Economou, and I. Kaganovich, “Effect of non-local electron conductivity on power absorption and plasma density profiles in low pressure inductively coupled discharges,” Plasma Sources Sci. Technol., 12, 170 (2003).

96. D. Kim, D. J. Economou, J. R. Woodworth, P. A. Miller, R. J. Shul, I. C. Abraham, B. P. Aragon, and T. W. Hamilton, “Plasma Molding Over Surface Topography: Simulation and Measurement of Ion Fluxes, Energies and Angular Distributions Over Trenches in RF High Density Plasmas,” IEEE Trans. Plasma Sci., 31, 691-702 (2003).

95. J. R. Woodworth, P. A. Miller, R. J. Shul, I. C. Abraham, B. P. Aragon, T. W. Hamilton, C. G. Willison, D. Kim, and D. J. Economou, “An experimental and theoretical study of ion distributions near 300-μm-tall steps on rf-biased wafers in high density plasmas,” J. Vac. Sci. Technol. A 21, 147-155 (2003).

94. B. Ramamurthi and D. J. Economou, “Pulsed Power Plasma Reactors: Two Dimensional Electropositive Discharge Simulation in a GEC Reference Cell,” Plasma Sources Science and Technology, 11, 324-332 (2002).

93. D. Kim and D. J. Economou, “Plasma Molding over Surface Topography: Simulation of Ion Flow and Energy and Angular Distributions over Steps in RF High Density Plasmas,” IEEE Trans. Plasma Sci., 30(5), 2048-2058 (2002).

92. Doosik Kim and Demetre J. Economou, “Plasma Molding over Surface Topography,” JSME International Journal, Series B, 45(1), 117-122 (2002).

91. C.-K. Kim and D. J. Economou, “Plasma Molding over Surface Topography: Energy and Angular Distributions of Ions Extracted out of Large Holes,” J. Appl. Phys., 91, 2594-2603, (2002).

90. D. Kim and D. J. Economou, “Energy and angular distributions of ions and neutrals extracted from a slot in contact with a high density plasma,” IEEE Trans. Plasma Sci., 30(1), 126 (2002).

89. B. Ramamurthi and D. J. Economou, “Metastable argon density evolution in a pulsed ICP discharge,” IEEE Trans. Plasma Sci., 30(1), 152 (2002).

88. B. Ramamurthi and D. J. Economou, “Two-Dimensional Pulsed-Plasma Simulation of a Chlorine Discharge,” J. Vac. Sci. Technol. A, 20, 467-478 (2002).

87 V. Midha, B. Ramamurthi, and D. J. Economou, “Time Evolution of an Ion-Ion Plasma after the Application of a Direct Current Bias,” J. Appl. Phys., 91, 6282-6287 (2002).

86. T. Panagopoulos, V. Midha, D. Kim and D. J. Economou, “Three-Dimensional Simulation of Inductively Coupled Plasma Reactors,” J. Appl. Phys., 91, 2687-2696 (2002).

85. I. D. Kaganovich, B. N. Ramamurthi, and D. J. Economou, “Spatiotemporal Dynamics of Charged Species in the Afterglow of Plasmas Containing Negative Ions,” Phys. Rev. E, 64, 036402, (2001).

84. V. Midha and D. J. Economou, “Dynamics of an Ion-Ion Plasma under Radio Frequency Bias,” J. Appl. Phys., 90, 1102 (2001).

83. B. Ramamurthi and D. J. Economou, "Two-dimensional simulation of a pulsed electronegative discharge," Journal de Physique (IV), 11(Pr3), 163-169 (2001).

82. S. Panda, D. J. Economou, and L. Chen, “Anisotropic Etching of Polymer Thin Films by High Energy (100s of eV) Oxygen Atom Neutral Beams,” J. Vac. Sci. Technol., A19, 398-404 (2001).

81. S. K. Kanakasabapathy, L. J. Overzet, V. Midha, and D. J. Economou, “Alternating Fluxes of Positive and Negative Ions from an Ion-Ion Plasma," Appl. Phys. Lett., 78, 22-24 (2001).

80. D. J. Economou, “Modeling and Simulation of Plasma Etching Reactors for Microelectronics,” Thin Solid Films, 365, 348-367 (2000).

79. J. Feldsien, D. Kim, and D. J. Economou, "SiO2 Etching in Inductively Coupled Plasmas: Surface Chemistry and Two-Dimensional Simulations,” Thin Solid Films, 374, 311-325 (2000).

78. V. Midha and D. J. Economou, "Spatiotemporal Evolution of a Pulsed Chlorine Discharge," Plasma Sources Sci. Technol., 9, 256-269 (2000).

77. S. Panda, D. J. Economou, and M. Meyyappan, “Effect of Metastable Oxygen Molecules in High-Density Power Modulated Oxygen Discharges,” J. Appl Phys.,87, 8323-8333 (2000).

76. I. Kaganovich, D.B. Ramamurthi, and D. J. Economou, “Self-Trapping of Negative Ions due to Electron Detachment in the Afterglow of Electronegative Gas Plasmas,” Appl. Phys. Lett., 76, 2844-2846 (2000).

75. I. Kaganovich, D. J. Economou, B. N. Ramamurthi, and V. Midha, “Negative Ion Density Fronts During Ignition and Extinction of Plasmas in Electronegative Gases,” Phys. Rev. Lett., 84, 1918-1921 (2000).

74. S.-K. Nam, C. B. Shin, and D. J. Economou, "Two-dimensional plasma reactor simulation with self-consistent coupling of gas flow with plasma transport,” Materials Science in Semiconductor Processing,” 2, 271-279 (1999).

73. C.-K. Kim, N. A. Kubota, and D. J. Economou, “Molecular Dynamics Simulation of Silicon Surface Smoothing by Low-Energy Argon Cluster Impact,” J. Appl. Phys., 86(12), 6758-6762 (1999).

72. S. Panda, J. Kim, B. H. Weiller, D. J. Economou, and D. M. Hoffman, “Low Temperature Chemical Vapor Deposition of Titanium Nitride Films from Tetrakis(ethylmethylamido)titanium and ammonia,” Thin Solid Films, 357, 125-131 (1999).

71. N. Gupta, V. Midha, V. Balakotaiah, and D. J. Economou, “Bifurcation Analysis of Thermal Runaway in Microwave Heating of Ceramics,” J. Electrochem. Soc., 146(2), 4659-4665 (1999).

70. N. A. Kubota, and D. J. Economou, “A Molecular Dynamics Simulation of Ultrathin Oxide Films on Silicon: Growth by Thermal O Atoms and Sputtering by 100 eV Ar+ Ions,” IEEE Trans. Plasma Sci., 27(5), 1416-1425 (1999).

69. N. A. Kubota, and D. J. Economou, “Molecular Dynamics Simulations of Ion-Induced Rearrangements of Ultrathin Oxide Films on Silicon,” IEEE Trans. Plasma Sci., 27, 106 (1999).

68. D. J. Economou, N. A. Kubota, and R. S. Wise, “Plasmoid Formation and Multiple Steady States in a Low Pressure Inductively Coupled Electronegative Plasmas,” IEEE Trans. Plasma Sci., 27, 60 (1999).

67. T. Panagopoulos and D. J. Economou, “Plasma Sheath Model and Ion Energy Distribution for All Radio Frequencies,”J. Appl. Phys., 85, 3435 (1999).

66. D. J. Economou, T. L. Panagopoulos, and M. Meyyappan, "Examining Scale-Up and Computer Simulation in Tool Design for 300-mm wafer Processing," Micro, 16(7), 101-113 (1998).

65. V. Midha and D. J. Economou, “A Two-Dimensional Model of Chemical Vapor Infiltration with Radio Frequency Heating II: Strategies to Achieve Complete Densification,” J. Electrochem. Soc., 145, 3569-3580 (1998).

64. N. A. Kubota, D. J. Economou, and S. Plimpton, “Molecular Dynamics Simulations of Low Energy (25-200 eV) Argon Ion Interactions with Silicon Surfaces: Sputter Yields and Product Formation Pathways,” J. Appl. Phys., 83, 4055-4063 (1998).

63. D. J. Economou, “Plasma Reactor Engineering,” in Advances in Electrochemistry and Electrochemical Engineering, Vol. 6, p. 237, edited by R. C. Alkire and D. M. Kolb, Wiley-VCH (1999).

62. D. J. Economou, J. Feldsien, and R. S. Wise, “Transport and Reaction in Inductively Coupled Plasmas for Microelectronics,” in Electron Kinetics and Applications of Glow Discharges, edited by U. Kortshagen and L. D. Tsendin, NATO Advanced Research Workshop, Plenum (1998).

61. V. I. Kolobov and D. J. Economou, “Ion-Ion Plasmas in Weakly Collisional Discharges in Electronegative Gases,” Appl. Phys. Lett., 72, 656-658 (1998).
 
60. D. P. Lymberopoulos, V. I. Kolobov, and D. J. Economou, “Fluid Simulation of a Pulsed-Power Inductively Coupled Argon Plasma,” J. Vac. Sci. Technol. A, 16, 564-571 (1998).

59. V. Midha and D. J. Economou, “A Two-Dimensional Model of Chemical Vapor Infiltration with Radio Frequency Heating,” J. Electrochem. Soc., 144, 4062-4071 (1997).

58. J. Johannes, T. Bartel, G. A. Hebner, J. Woodworth, and D. J. Economou, "Direct Simulation Monte Carlo of Inductively Coupled Plasma and Comparison with Experiments," J. Electrochem Soc., 144, 2448-2455 (1997).

57. V. I. Kolobov and D. J. Economou, "Anomalous Skin Effect in Gas Discharge Plasmas," Plasma Sources Sci. & Technol., 6, R1-R17 (1997).

56. S. Athavale and D. J. Economou, "Realization of Atomic Layer Etching (ALET) of Silicon," J. Vac. Sci. Technol. B, 14, 3702 (1996).

55. V. I. Kolobov, D. P. Lymberopoulos, and D. J. Economou, "Electron Kinetics and Non-Joule Heating in Near Collisionless Inductively Coupled Plasmas," Physical Review E, 55, 3408 (1997).

54. R. Wise, D. Lymberopoulos and D. J. Economou, "Rapid Two-Dimensional Self-Consistent Simulation of Inductively Coupled Plasma and Comparison with Experiments,"  Appl. Phys. Lett., 68, 2499 (1996).

53. D. Lymberopoulos, R. Wise, D. J. Economou, and T. Bartel "Ion Density and Temperature Distribution in an Inductively Coupled High Plasma Density Reactor," IEEE Trans. Plasma Sci.,  24, 129 (1996).
 
52. D. J. Economou and T. J. Bartel, "Direct Simulation Monte Carlo (DSMC) of Rarefied Gas Flow During Etching of Large Diameter (300 mm) Wafers," IEEE Trans. Plasma Sci., 24, 131 (1996).

51. D. M. Hoffman, S. P. Rangarajan, S. D. Athavale, D. J. Economou, J.-R. Liu, Z. Zheng, and W.-K. Chu, “Chemical vapor deposition of aluminum and gallium nitride thin films from metalorganic precursors," J. Vac. Sci. Technol. A, 14, 306-311 (1996).

50. J. Johannes, T. Bartel, D. Economou, D. Lymberopoulos and R. Wise, "Simulation Images from a Low Pressure Chlorine Plasma Reactor Using the Direct Simulation Monte Carlo Method,"  IEEE Trans. Plasma Sci., 24, 127 (1996).

49. D. J. Economou, "The Chemistry of Plasma Etching," in The Chemistry of Electronic Materials,  H. B. Pogge, editor, pp. 251-322, Marcel Dekker, Inc., 1996.

48. D. P. Lymberopoulos and D. J. Economou, “Two-Dimensional Self-Consistent Radio Frequency Plasma Simulations Relevant to the Gaseous Electronics Conference (GEC) Reference Cell," Journal of Research of the National Institute of Standards and Technology,” 100, 473-494 (1995).

47. P. Jiang, D. J. Economou, and C. B. Shin, “Effect of Power Modulation on Radical Concentration and Uniformity in a Single-Wafer Plasma Reactor,” Plasma Chemistry Plasma Process., 15, 383-408 (1995).

46. R. S. Wise, D. P. Lymberopoulos and D. J. Economou, “A Two-Region Model of a Radio Frequency Low-Pressure High-Density Glow Discharge," Plasma Sources Sci. Technol., 4, 317-331 (1995).

45. D. P. Lymberopoulos and D. J. Economou, “Two-Dimensional Simulation of Polysilicon Etching with Chlorine in a High Density Plasma Reactor,” IEEE Trans. Plasma Sci., 23, 573-580 (1995).

44. D. J. Economou, T. J. Bartel, R. S. Wise and D. P. Lymberopoulos, “Two-Dimensional Direct Simulation Monte Carlo (DSMC) of Reactive Ion and Neutral Flow in a High Density Plasma Reactor,” IEEE Trans. Plasma Sci., 23, 581-590 (1995).

43. D. P. Lymberopoulos and D. J. Economou, “Spatiotemporal Electron Dynamics in Radio Frequency Glow Discharges,” J. Phys. D: Appl. Phys., 28, 727-737 (1995).

42. D. M. Hoffman, S. P. Rangarajan, S. D. Athavale, D. J. Economou, J.-R. Liu, Z. Zheng, and W.-K. Chu, “Plasma enhanced chemical vapor deposition of silicon, germanium and tin nitride thin films from metal-organic precursors," J. Vac. Sci. Technol. A, 13, 820-825 (1995).

41. S. D. Athavale and D. J. Economou, “Molecular Dynamics Simulation of Atomic Layer Etching (ALET) of Silicon," J. Vac. Sci. Technol. A, 13, 966-971 (1995).

40. D. P. Lymberopoulos and D. J. Economou, "Modeling and Simulation of Glow Discharge Plasma Reactors," J. Vac. Sci. Technol. A, 12, 1229-1236 (1994).

39. N. L. Bassett and D. J. Economou, “Effect of Cl2 Additions to an Argon Glow Discharge,” J. Appl. Phys., 75, 1931-1939 (1994).

38. D. M. Hoffman, S. P. Rangarajan, S. D. Athavale, S. C. Deshmukh, D. J. Economou, J.-R. Liu, Z. Zheng, and W.-K. Chu, “Plasma Enhanced Chemical Vapor Deposition of Silicon Nitride Films from Metalorganic Precursors," J. Mater. Res., 12,  3019-3021 (1994).

37. D. M. Hoffman, S. P. Rangarajan, S. D. Athavale, D. J. Economou, J.-R. Liu, Z. Zheng, and W.-K. Chu, “Plasma Enhanced Metalorganic Chemical Vapor Deposition of Germanium Nitride Thin Films,” Mater. Res. Soc. Symp. Proc., 335, 3-7 (1994).

36. J. Morrel, D. J. Economou, and N. Amundson, "Chemical Vapor Infiltration of SiC with Volume Heating," J. Mater. Res., 8, 1057-1067 (1993).

35. D. P. Lymberopoulos and D. J. Economou, "Fluid Simulations of Glow Discharges: Effect of Metastable Atoms in Ar," J. Appl. Phys., 73, 3668-3679 (1993).

34. D. P. Lymberopoulos and D. J. Economou, "Fluid Simulations of Radio Frequency Glow Discharges: Two-Dimensional Argon Discharge Including Metastables," Appl. Phys. Lett., 63, 2478-2480 (1993).

33. P. Jiang and D. J. Economou, "Temporal Evolution of the Electron Energy Distribution Function in Oxygen and Chlorine Gases under DC and AC Fields," J. Appl. Phys., 73, 8151-8160 (1993).

32. C. R. Koemtzopoulos, D. J. Economou, and R. Pollard, "Hydrogen Dissociation in a Microwave Discharge for Diamond Deposition," Diamond and Related Materials, 2, 25-35 (1993).

31. E. S. Aydil and D. J. Economou, "Modeling of Plasma Etching Reactors Including Wafer Heating Effects," J. Electrochem. Soc., 140, 1471-1481 (1993).

30. S. Deshmukh and D. J. Economou, "Remote Plasma Etching Reactors: Modeling and Experiment," J. Vac. Sci. Technol. B, 11, 206-215 (1993).

29. Q. Xiong, Y. Y. Xue, P. Hor, C. W. Chu, M. Davis, J. Wolfe, S. Deshmukh, and D. Economou, "Effect of pressure on the critical current density of YBa₂Cu₃O_7-δ thin films," Physica C,  205, 307 (1993).

28. S. Deshmukh and D. J. Economou, "Factors Affecting the Cl Atom Density in a Chlorine Discharge," J. Appl. Phys., 72, 4597-4607 (1992).

27. J. Morrel, D. J. Economou, and N. Amundson, "Pulsed-Power Volume-Heating Chemical Vapor Infiltration," J. Mater. Res. 7, 2447-2457 (1992).

The following two papers won the Young Author Best Paper Award by the Journal of the Electrochemical Society in 1992.

26. E. Aydil and D. Economou, “Combined Theoretical and Experimental Investigations of Chlorine RF Glow Discharges. I: Theoretical,” J. Electrochem. Soc., 139, 1396-1406 (1992).

25. E. Aydil and D. Economou, “Combined Theoretical and Experimental Investigations of Chlorine RF Glow Discharges. II: Experimental,” J. Electrochem. Soc., 139, 1406-1412 (1992).
 
24. F. Fong, S. Deshmukh, M. Davis, D. Stumbo, J. Wolfe, and D. Economou, "Resolution Limits of Ion Milling for Fabricating Y1Ba2Cu3Ox Nanostructures," J. Appl. Phys., 71, 2461 (1992).

23. J. Morrel, D. Economou and N. Amundson, "A Mathematical Model for Chemical Vapor Infiltration with Volume Heating," J. Electrochem. Soc., 139, 328-336 (1992).

22. Y. J. Zhao, W. K. Chu, M. F. Davis, J. C. Wolfe, S. C. Deshmukh, D. J. Economou, and A. McGuire, "Radiation Damages and Flux Pinning in YBCO Thin Films," Physica C, 184, 144-148  (1991).

21. Eray Aydil and D. Economou, “Multiple Steady-States in a Radio Frequency Chlorine Glow Discharge,” J. Appl. Phys., 69, 109-114 (1991).

20. C. B. Shin and D. Economou, “Forced and Natural Convection Effects on the Shape Evolution of Cavities during Wet Chemical Etching,” J. Electrochem. Soc., 138, 527-538 (1991).

19. S.-K. Park and D. Economou, “A Mathematical Model for Etching of Silicon Using Tetrafluoromethane in a Radial Flow Plasma Reactor," J. Electrochem. Soc., 138, 1499-1508 (1991).

18. D. Economou, E. Aydil, and G. Barna, "In Situ Monitoring of Etching Uniformity in Plasma Reactors," Solid State Technology, 34, 107-111 (1991).

17. M. Davis, J. Wosik, K. Foster, S. Deshmukh, H. Rampersad, S. Shah, P. Siesmen, D. Economou, and J. Wolfe, “Deposition of High Quality Y1Ba2Cu3Ox Thin Films over Large Areas by Pulsed Laser Ablation with Substrate Scanning," J. Appl. Phys., 69, 7182-7188 (1991).

16. Ping Jiang and D. Economou, "Wet Etching of GaAs Using a Novel Rotating Cell Reactor," J. Electrochem. Soc., 138, L28-L29 (1991).

15. Y. J. Zhao, W. K. Chu, D. K. Christen, E. C. Jones, M. F. Davis, J. C. Wolfe, S. C. Deshmukh, and D. J. Economou, "Linewidth Dependence of Critical Current Density in Y1Ba2Cu3Ox Thin Film Microbridges," Appl. Phys. Lett., 59, 1129-1131 (1991).
 
14. S.-K. Park and D. Economou, “Numerical Simulation of a Single-Wafer Isothermal Plasma Etching Reactor,” J. Electrochem. Soc., 137, 2624-2634 (1990).

13. C. B. Shin and D. Economou, “Mass Transfer by Natural and Forced Convection in Open Cavities,” Int. J. Heat Mass Transfer, 33, 2191-2205 (1990).

12. S.-K. Park and D. Economou, “Analysis of a Pulsed-Plasma Chemical Vapor Deposition Reactor with Recycle,” J. Electrochem. Soc., 137, 2103-2116 (1990).

11. S.-K. Park and D. Economou, “Parametric Studies of a Radio Frequency Glow Discharge Using a Continuum Model," J. Appl. Phys., 68, 4888-4890 (1990).

10. S.-K. Park and D. Economou, “Analysis of Low Pressure RF Glow Discharges Using a Continuum Model," J. Appl. Phys., 68, 3904-3915 (1990).

9. D. Economou, S.-K. Park, and G. Williams, “Uniformity of Etching in Parallel Plate Plasma Reactors,” J. Electrochem. Soc., 136, 188-198 (1989).

8. C. B. Shin and D. Economou, “Effect of Transport and Reaction on the Shape Evolution of Cavities during Wet Chemical Etching,” J. Electrochem. Soc., 136, 1997-2004 (1989).

7. S.-K. Park and D. Economou, “A Mathematical Model for a Plasma-Assisted Downstream Etching Reactor,” J. Appl. Phys., 66, 3256-3267 (1989).

6. D. Economou and R. Alkire, “Effect of Potential Field on Ion Deflection and Shape Evolution of Trenches during Plasma-Assisted Etching,” J. Electrochem. Soc., 135, 941-949 (1988).

5. D. Economou, D. Evans, and R. Alkire, “A Time-Average Model of the RF Plasma Sheath,” J. Electrochem. Soc., 135, 756-763 (1988).

4. D. Economou  and R. Alkire, “A Mathematical Model for a Parallel Plate Plasma Etching Reactor,” J. Electrochem. Soc., 135, 2786-2794 (1988).

3. D. Economou and R. Alkire, “Two-Phase Mass Transfer in Channel Electrolyzers with Gas-Liquid Flow,” J. Electrochem. Soc., 132, 601-608 (1985).

2. R. Alkire and D. Economou, “Transient Behavior during Film Removal in Diffusion-Controlled Plasma Etching,” J. Electrochem. Soc., 132, 648-656 (1985).

1. C. Philippopoulos, D. Economou, C. Economou, and J. Marangozis, “Norbornadiene-Quadricyclane System in the Photochemical Conversion and Storage of Solar Energy,” Ind. Eng. Chem. Prod. Res. Dev., 22, 627 (1983).

Papers in Proceedings Volumes (asterisk * refers to a refereed paper)

28. B. White, Q. Wang, D. J. Economou, P. J. Wolf, T. Jacobs, and J. Fourcher, “Neutral oxygen beam stripping of photoresist on porous ultra low-k materials,” in Proceedings of the IEEE International Interconnect Technology Conference, June 2-4, 2003 San Francisco, p. 153 (2003).

*27. D. Kim and D. J. Economou, “Multidimensional Plasma Sheaths and Resulting Ion/Fast Neutral Distributions at the Substrate Surface,” in Proceedings of the Seventh International Symposium on Sputtering and Plasma Processes,” ISSP 2003, pp. 55-62, June 11-13, 2003, Kanazawa, Ishikawa, Japan.

*26. Chang-Koo Kim and Demetre J. Economou, “Energy and Angular Distribution of Ions Extracted from a Large Hole in Contact with a High Density Plasma,” in Proceedings of the Symposium Fundamental Gas-Phase and Surface Chemistry in Vapor-Phase Deposition II, and Process Control, Diagnostics and Modeling in Semiconductor Manufacturing IV, edited by M. T. Swihart, M. D. Allendorf and M. Meyyappan, The Electrochemical Society, vol. PV 2001-13, pp. 308-315 (2001).

*25. Badri Ramamurthi and Demetre J. Economou, “Two-Dimensional Simulation of Pulsed power Electronegative Plasmas,” in Proceedings of the Symposium Fundamental Gas-Phase and Surface Chemistry in Vapor-Phase Deposition II, and Process Control, Diagnostics and Modeling in Semiconductor Manufacturing IV, edited by M. T. Swihart, M. D. Allendorf and M. Meyyappan, The Electrochemical Society, vol. PV 2001-13, pp. 405-414 (2001).

*24. D. J. Economou, “Multiscale Modeling in Plasma Engineering and Parallels to Electrochemical Engineering,” in Tutorials in Electrochemical Engineering-Mathematical Modeling, Electrochemical Society Proceedings Volume, R. F. Savinell, editor, August 1999.

*23. V. Midha and D.J. Economou, “Effect of Geometry on CVI with RF Heating", Ceramic Engineering and Science Proceedings, 19(3-4), (1998).

*22. V. Midha and D. J. Economou, “A Two-Dimensional Model of Chemical Vapor Infiltration with Radio Frequency Heating,” in Proceedings of the Fourteenth International Conference on Chemical Vapor Deposition and EUROCVD-11, Paris, France, edited by M. D. Allendorf and C. Bernard, The Electrochemical Society Proceedings Volume PV 97-25, pp. 528-535 (1997).

21. D. J. Economou, “Direct Simulation Monte Carlo (DSMC) of Low Pressure Plasma Reactors,” in Proceedings of the International Symposium on Plasma and Fluid Simulation for Materials Processing, edited by K. Nanbu, Vol. 10, pp. 83-90, published by the Institute of Fluid Science, Tohoku University, Sendai, Japan (1997).

*20. J. Feldsien and D. J. Economou, “Parametric Investigation of Plasma Uniformity in a Dome-Shaped Inductively Coupled Plasma Reactor,” in Proceedings of the 2nd International Symposium on Control, Diagnostics, and Modeling in Semiconductor Manufacturing, M. Meyyappan, D. J. Economou, and S. W. Butler, eds., The Electrochemical Society Inc.,  Vol. 97-9, pp. 260-267 (1997).

19. R. S. Wise, D. P. Lymberopoulos and D. J. Economou, “A TCAD Simulation Tool for Inductively Coupled Plasma Reactors and Comparison with Experiments,” in Proceedings of the 11th Plasma Processing Symposium,  edited by G. S. Mathad, M. Meyyappan,  and D. W. Hess, The Electrochemical Society, PV-96-12, 11-19 (1996).  

18. D. J. Economou and T. Bartel, “Direct Simulation Monte Carlo (DSMC) of Semiconductor Manufacturing Processes,” in Proceedings of the 11th Plasma Processing Symposium,  edited by G. S. Mathad, M. Meyyappan,  and D. W. Hess, The Electrochemical Society, PV-96-12, 70-82  (1996).

17. J. Johannes, T. Bartel, D. J. Economou, G. Hebner, R. Wise, and J. Woodworth, "Direct Simulation Monte Carlo of Inductively Coupled Plasma and Comparison with Experiments," in Proceedings of the 11th Plasma Processing Symposium,  edited by G. S. Mathad, M. Meyyappan,  and D. W. Hess, The Electrochemical Society, PV-96-12, 20-38 (1996).

16. D. J. Economou, D. M. Hoffman, S. P. Rangarajan, S. D. Athavale, J.-R. Liu, Z. Zheng, and W.-K. Chu, “Chemical Vapor Deposition of Aluminum and Gallium Nitride Thin Films from Metalorganic Precursors," in Proceedings of the Symposium on III-V Nitride Materials and Processes, edited by T. Moustakas and J. P. Dismukes, and S.J. Pearton, The Electrochemical Society Inc., Vol. 96-11,  p. 69 (1996).

*15. D. P. Lymberopoulos R. Wise, and D. J. Economou, Modeling and Simulation of Two-Dimensional Reactive Plasma Flow in Inductively Coupled Reactors, in Proceedings of the 1st International Symposium on Control, Diagnostics, and Modeling in Semiconductor Manufacturing, M. Meyyappan, D. J. Economou, and S. W. Butler, eds., The Electrochemical Society Inc.,  Vol. 95-2, pp. 588-595 (1995).

14. D. P. Lymberopoulos and D. J. Economou, Modeling and Simulation of Inductively Coupled High Density Plasma Sources, in Proceedings of the 10th Plasma Processing Symposium,  edited by G. S. Mathad and D. W. Hess, The Electrochemical Society, Vol. 94-20, pp. 1-12 (1994).

13. C. R. Koemtzopoulos, D. J. Economou, and R. Pollard, "Influence of Substrate Placement on Plasma-Assisted Chemical Vapor Deposition of Diamond," in The Synthesis and Processing of Electronic Materials, Topical Conference Preprints, AIChE Conference, San Francisco, CA, Nov. 1994.

12. D. J. Economou, "Developments in Wet Etching and Deposition for Pattern Delineation," in Trends in Electrochemistry, Council of Scientific Research Integration (1993).

11. D. J. Economou and D. P. Lymberopoulos, "Self-Consistent Simulation of RF Glow Discharges Coupled with Neutral Transport and Reaction," in Proc. 3rd International Symp. on Process Phys. and Modeling in Semicond. Technol., G. R. Srinivasan, K. Taniguchi, and C. S. Murthy, eds., The Electrochemical Society Inc., 93-6 (1993).

10. S. Deshmukh, S. Athavale and D. J. Economou, "Radical Beam Etching: Application to Patterning of YBa2Cu3O6+x High Tc Superconducting Thin Films," in Proc. of International Symp. on Highly Selective Dry Etching and Damage Control, G. S. Mathad and Y. Horiike, eds., The Electrochemical Society Inc., 93-21, 235 (1993).

9. D. J. Economou, "Modeling Potential Distribution, Transport and Reaction in Gas Plasmas," in Proc. of the 2nd International Symp. on Electrochemical Processing of Tailored Materials," R. C. Alkire, N. Masuko, Y. Ito, D. R. Sadoway, and D. J. Economou, eds., The Electrochemical Society Inc., 93-12, 1 (1993).

8. E. S. Aydil and D. J. Economou, "Modeling of Plasma Etching Reactors Including Wafer Heating Effects," in Proc. 9th Plasma Process. Symp., The Electrochemical Society Inc., edited by G. S. Mathad and D. W. Hess, 92-18, 22 (1992).
 
7. E. Aydil and D. Economou, "Experimental and Modeling Studies of Chlorine RF Glow Discharges," in Proc. 8th Plasma Process. Symp., The Electrochemical Society Inc., edited by G. S. Mathad and D. W. Hess, 90-14, 77 (1990).

6. D. Economou and S.-K. Park, "Modeling and Analysis of Pulsed Plasma CVD and Etching Reactors," in Proc. 8th Plasma Process. Symp., The Electrochemical Society Inc., edited by G. S. Mathad and D. W. Hess, 90-14, 185 (1990).

5. G. Barna, J. Spatafora, E. Aydil, and D. Economou, "Spectroscopic Measurement of Etchant Concentration Profiles in a Parallel Plate Plasma Reactor," in Proceedings of the Society of Manufacturing Engineers, MS90-476, pp. 1-12, 1990.

4. J. Wosik, T. Robin, M. Davis, J. C. Wolfe, K. Foster, S. Deshmukh, A. Bensaoula, R. Sega, D. Economou, and A. Ignatiev, "Dependence of Millimeter Wave Surface Resistance on the Deposition Parameters of Laser Ablated Y1Ba2Cu3Ox Thin Films," p. 539 in Proceedings of the 2nd Conference on the Science and Technology of Thin Film Superconductors, Denver, Co, 1990.

3. D. Economou, S.-K. Park, and G. Williams, "Parallel Plate Plasma Etching Reactor Modeling: Uniformity of Etching," in Proc. of the 7th Plasma Process. Symp., The Electrochemical Society Inc., edited by G. S. Mathad, G. C. Schwartz, and D. W. Hess, 88-22, 17 (1988).

2. D. Economou and R. Alkire, in Proceedings of the Advances in the Chlor-Alkali and Chlorate Industry, The Electrochemical Society Inc., 1985.

1. D. Economou and R. Alkire, in Proceedings of the 5th Symposium on Plasma Processing, The Electrochemical Society Inc., 1985.

Patents

U. S. Patent #4,859,277 “Method for Measuring Plasma Properties in Semiconductor Processing,” with G. Barna.

Patent Pending, “Hyperthermal Neutral Beam Source and Method for Operating,” with L. Chen and V. Donnelly.

Patent Pending, “Method and Apparatus for Nanopantography,” with V. Donnelly, P. Ruchhoeft, L. Xu; S. C. Vemula; and M. Jain.

Book Review

D. J. Economou, "Computational Modeling in Semiconductor Manufacturing," AIChE Journal (book review), 1996.

Edited Volumes

Proceedings of the 2nd International Symposium on Electrochemical Processing of Tailored Materials, R. C. Alkire, N. Masuko, Y. Ito, D. R. Sadoway, and D. J. Economou, eds., The Electrochemical Society Inc., Vol. 93-12 (1993).

Proceedings of the 1st International Symposium on Control, Diagnostics, and Modeling in Semiconductor Manufacturing, M. Meyyappan, D. J. Economou, and S. W. Butler, eds., The Electrochemical Society Inc., Vol. 95-2 (1995).

Proceedings of the 2nd International Symposium on Control, Diagnostics, and Modeling in Semiconductor Manufacturing, M. Meyyappan, D. J. Economou, and S. W. Butler, eds., The Electrochemical Society Inc., Vol. 97-9 (1997).

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