Pulsed plasma etching for semiconductor manufacturing

Journal of Physics D: Applied Physics

Volumn 47, Issue 30, 2014, Pages

  Economou, Demetre J ^a  

^a UNIVERSITY OF HOUSTON   (United States)

Author keywords

microelectronics; plasma processing; pulsed plasma

Indexed keywords

ASPECT RATIO; MICROELECTRONICS; PLASMA APPLICATIONS; PLASMA ETCHING; SEMICONDUCTOR DEVICE MANUFACTURE;

ASPECT RATIO DEPENDENT ETCHINGS; CONTINUOUS WAVES; ELECTRON ENERGY DISTRIBUTION FUNCTIONS; ION ENERGY AND ANGULAR DISTRIBUTION; PULSED PLASMA; SEMICONDUCTOR MANUFACTURING; SPECIES DENSITY; VACUUM ULTRAVIOLETS;

PLASMAS;

EID: 84903974329     PISSN: 00223727     EISSN: 13616463     Source Type: Journal    
DOI: 10.1088/0022-3727/47/30/303001     Document Type: Review

References (134)

1. Lieberman M A and Lichtenberg A J 2005 Principles of Plasma Discharges and Materials Processing 2nd edn (New York: Wiley-Interscience)
2. Franz G 2009 Low Pressure Plasmas and Microstructuring Technology (Berlin: Springer)
3. Kong M G, Kroesen G, Morfill G, Nosenko T, Shimizu T, van Dijk J and Zimmermann J L 2009 Plasma medicine: an introductory review New J. Phys. 11 115012
4. Cheung K P 2001 Plasma Charging Damage (London: Springer)
5. Shin H, Zhu W, Economou D J and Donnelly V M 2012 Surprising importance of photo-assisted etching of silicon in chlorine-containing plasmas J. Vac. Sci. Technol. A 30 021306
6. Cheung K P and Chang C P 1994 Plasma-charging damage: a physical model J. Appl. Phys. 75 4415
7. Arnold J C and Sawin H H 1991 Charging of pattern features during plasma etching J. Appl. Phys. 70 5314
8. Economou D J and Alkire R C 1988 Effect of potential field on ion deflection and shape evolution of trenches during plasma-assisted etching J. Electrochem. Soc. 135 941
9. Kinoshita T, Hane M and McVittie J 1996 Notching as an example of charging in uniform high density plasmas J. Vac. Sci. Technol. B 14 560
10. Hwang G S and Giapis K P 1997 On the origin of the notching effect during etching in uniform high density plasmas J. Vac. Sci. Technol. B 15 70
11. Watanabe M, Shaw D M and Collins G J 2001 Reduction of microtrenching and island formation in oxide plasma etching by employing electron beam charge neutralization Appl. Phys. Lett. 79 2698
12. Gottscho R A, Jurgensen C W and Vitkavage D J 1992 Microscopic uniformity in plasma etching J. Vac. Sci. Technol. B 10 2133
13. Samukawa S and Mieno T 1996 Pulse-time modulated plasma discharge for highly selective, highly anisotropic and charge-free etching Plasma Sources Sci. Technol. 5 132
14. Samukawa S, Ohtake H and Mieno T 1996 Pulse-time-modulated electron cyclotron resonance plasma discharge for highly selective, highly anisotropic, and charge-free etching J. Vac. Sci. Technol. A 14 3049 (Pubitemid 126157157)
15. Samukawa S 1994 Pulse-time-modulated electron cyclotron resonance plasma etching for highly selective, highly anisotropic, and notch-free polycrystalline silicon patterning Appl. Phys. Lett. 64 3398
16. Shibayama T, Shindo H and Horiike Y 1996 Silicon etching by alternating irradiations of negative and positive ions Plasma Sources Sci. Technol. 5 254
17. Petit-Etienne C, Darnon M, Vallier L, Pargon E, Cunge G, Boulard F, Joubert O, Banna S and Lill T 2010 Reducing damage to the Si substrate during gate etching processes by synchronous plasma pulsing J. Vac. Sci. Technol. B 28 926
18. Sugai H, Nakamura K, Hikisaka Y and Nakamura M 1995 Diagnostics and control of radicals in an inductively coupled etching reactor J. Vac. Sci. Technol. A 13 887
19. Samukawa S 1993 Time-modulated electron cyclotron resonance discharge for controlling the polymerization in SiO2 etching Japan. J. Appl. Phys. 32 6080
20. Shin K S, Shi K K, Kang C J, Jung C, Jung C O, Moon J T and Lee M Y 1998 Enhancement of mask selectivity in SiO2 etching with a phase-controlled pulsed inductively couple plasma Japan. J. Appl. Phys. 37 2349
21. Boswell R W and Porteous R K 1987 Etching in a pulsed plasma J. Appl. Phys. 62 3123
22. Jiang P, Economou D J and Shin C B 1995 Effect of power modulation on radical concentration and uniformity in a single-wafer plasma reactor Plasma Chem. Plasma Process. 15 383
23. Verdeyen J, Beberman J and Overzet L 1990 Modulated discharges: effect on plasma parameters and deposition J. Vac. Sci. Technol. A 8 1851
24. Bouchoule A and Ranson P 1991 Study of volume and surface processes in low pressure radio frequency plasma reactors by pulsed excitation methods: I. Hydrogen-argon plasma J. Vac. Sci. Technol. A 9 317
25. Bouchoule A, Plain A, Boufendi L, Blondeau J Ph and Laure C 1991 Particle generation and behavior in a silane-argon low-pressure discharge under continuous or pulsed radio-frequency excitation J. Appl. Phys. 70 1991
26. Watanabe Y, Shiratani M and Makino H 1990 Powder-free plasma chemical vapor deposition of hydrogenated amorphous silicon with high rf power density using modulated rf discharge Appl. Phys. Lett. 57 1616
27. Park S-K and Economou D J 1991 Analysis of a pulsed-plasma chemical vapor deposition reactor with recycle J. Electrochem. Soc. 138 1499
28. Subramonium P and Kushner M J 2004 Pulsed plasmas as a method to improve uniformity during materials processing J. Appl. Phys. 96 82
29. Banna S, Agarwal A, Cunge G, Darnon M, Pargon E and Joubert O 2012 Pulsed high-density plasma for advanced dry etching processes J. Vac. Sci. Technol. A 30 040801
30. Tserepi A D, Dunlop J R, Preppernau B L and Miller T A 1992 Effect of surfaces on H-atom concentration in pulsed and continuous discharges J. Vac. Sci. Technol. A 10 1188
31. Kiss L D B and Sawin H H 1992 Comparison of CF3Cl and C2F6 + Cl2 plasma chemistry by power modulation J. Electrochem. Soc. 139 1414
32. Xu L, Economou D J, Donnelly V M and Ruchhoeft P 2005 Extraction of a nearly monoenergetic ion beam from a pulsed plasma Appl. Phys. Lett. 87 041502 (Pubitemid 41117948)
33. Shin H, Zhu W, Xu L, Ouk T, Economou D J and Donnelly V M 2011 Control of ion energy distributions using a pulsed plasma with synchronous bias on a boundary electrode Plasma Sources Sci. Technol. 20 055001
34. Logue M D, Shin H, Zhu W, Xu L, Donnelly V M, Economou D J and Kushner M J 2012 Ion energy distributions in inductively coupled plasmas having a biased boundary electrode Plasma Sources Sci. Technol. 21 065009
35. Lafleur T and Booth J P 2012 Control of the ion flux and ion energy in CCP discharges using non-sinusoidal voltage waveforms J. Phys. D: Appl. Phys. 45 395203
36. Lampe M, Manheimer W M, Fernsler R F, Slinker S P and Joyce G 2004 The physical and mathematical basis of stratification in electronegative plasmas Plasma Sources Sci. Technol. 13 15
37. Daniels P G, Franklin R N and Snell J 1990 The contracted positive column in electronegative gases J. Phys. D: Appl. Phys. 23 823
38. Tsendin L D 1989 Plasma stratification in a discharge in an electronegative gas Sov. Phys. - Tech. Phys. 34 11
39. Kaganovich I D, Franklin R N and Demidov V I 2010 Principles of transport in multicomponent plasmas Introduction to Complex Plasmas ed M Bonitz et al (Berlin: Springer) pp 17-39
40. Kouznetsov I G, Lichtenberg A J and Lieberman M A 1999 Internal sheaths in electronegative discharges J. Appl. Phys. 86 4142
41. Kolobov V I and Economou D J 1998 Ion-ion plasmas and double layer formation in weakly collisional electronegative discharges Appl. Phys. Lett. 72 656 (Pubitemid 128672371)
42. Kono A 1999 Formation of an oscillatory potential structure at the plasma boundary in electronegative plasmas J. Phys. D: Appl. Phys. 32 1357
43. Samukawa S 1996 Pulse-time-modulated electron cyclotron resonance plasma etching with low radio-frequency substrate bias Appl. Phys. Lett. 68 316 (Pubitemid 126683712)
44. Maruyama T, Fujiwara N, Ogino S and Miyatake H 1998 Reduction of charge build-up with pulse-modulated bias in pulsed electron cyclotron resonance plasma Japan. J. Appl. Phys. 37 2306
45. Midha V and Economou D J 2000 Spatiotemporal evolution of a pulsed chlorine discharge Plasma Sources Sci. Technol. 9 256
46. Hebner G A and Fleddermann C B 1997 Characterization of pulse-modulated inductively coupled plasmas in argon and chlorine J. Appl. Phys. 82 2814
47. Malyshev M V, Donnelly V M, Colonell J I and Samukawa S 1999 Dynamics of pulsed-power chlorine plasmas J. Appl. Phys. 86 4813
48. Ahn T H, Nakamura K and Sugai H 1996 Negative ion measurements and etching in a pulsed power inductively coupled plasma in chlorine Plasma Sources Sci. Technol. 5 139
49. Economou D 2007 Fundamentals and applications of ion-ion plasmas Appl. Surf. Sci. 253 6672 (Pubitemid 46734486)
50. Rogoff G L 1985 Ambipolar diffusion coefficients for discharges in attaching gases J. Phys. D: Appl. Phys. 18 1533
51. Malyshev M V and Donnelly V M 2000 Dynamics of inductively-coupled pulsed chlorine plasmas in the presence of continuous substrate bias Plasma Sources Sci. Technol. 9 353
52. Ashida S and Lieberman M A 1997 Spatially averaged (global) model of time modulated high density chlorine plasmas Japan. J. Appl. Phys. 36 854
53. Meyyappan M 1997 Modeling of pulsed-power SF6 plasma Japan. J. Appl. Phys. 36 4820
54. Meyyappan M 1996 Analysis of pulse-time modulated high density plasmas J. Vac. Sci. Technol. A 14 2122 (Pubitemid 126101956)
55. Kaganovich I D and Tsendin L D 1993 Formation of discontinuities in multistage evolution associated with diffusion of a multicomponent weakly ionized hot-electron plasma Plasma Phys. Rep. 19 645
56. Kaganovich I D, Ramamurthi B N and Economou D J 2001 Spatiotemporal dynamics of charged species in the afterglow of plasmas containing negative ions Phys. Rev. E 64 036402
57. Kaganovich I D, Economou D J, Ramamurthi B N and Midha V 2000 Negative ion density fronts during ignition and extinction of plasmas in electronegative gases Phys. Rev. Lett. 84 1918
58. Brihoum M, Cunge G, Darnon M, Gahan D, Joubert O and Braithwaite N St J 2013 Ion flux and ion distribution function measurements in synchronously pulsed inductively coupled plasmas J. Vac. Sci. Technol. A 31 020604
59. Lichtenberg A J, Vahedi V, Lieberman M A and Rognlien T 1994 Modeling electronegative plasma discharges J. Appl. Phys. 75 2339
60. Thorsteinsson E G and Gudmundsson J T 2010 A global (volume-averaged) model of a Cl2/Ar discharge: II. Pulsed power modulation J. Phys. D: Appl. Phys. 43 115202
61. Smith D, Dean A G and Adams N G 1974 Space charge fields in afterglow plasmas J. Phys. D: Appl. Phys. 7 1944
62. Gutsev S A, Kudryavtsev A A and Romanenko V A 1995 Formation of an ion-ion plasma as a result of electron runaway in the pauses of pulsed discharge in oxygen Tech. Phys. 40 1131
63. Kudryavtsev A A and Tsendin L D 2000 On the possibility of negative ion concentration growth between pulses of discharge current in oxygen Tech. Phys. Lett. 26 582
64. Belostotsky S G, Economou D J, Lopaev D V and Rakhimova T V 2005 Negative ion destruction by O(3P) atoms and O2(a 1Δg) molecules in an oxygen plasma Plasma Sources Sci. Technol. 14 532 (Pubitemid 41165133)
65. Hansen S G, Luckman G and Colson S D 1988 Measurements of F*, CF and CF2 formation and decay in pulsed fluorocarbon discharges Appl. Phys. Lett. 53 1588
66. Takahashi K, Hori M and Goto T 1993 Control of fluorocarbon radicals by on-off modulated electron cyclotron resonance plasma Japan. J. Appl. Phys. Part 2 32 L1088
67. Booth J P, Cunge G, Chabert P and Sadeghi N 1999 CFx radical production and loss in a CF4 reactive ion etching plasma: fluorine-rich conditions J. Appl. Phys. 85 3097
68. Cunge G and Booth J P 1999 CF2 production and loss mechanisms in fluorocarbon discharges: fluorine-poor conditions and polymerization J. Appl. Phys. 85 3952
69. Goto T and Hori M 1996 Radical behavior in fluorocarbon plasma and control of silicon oxide etching by injection of radicals Japan J. Appl. Phys. Part I 35 6521
70. Vempaire D and Cunge G 2009 Probing radical kinetics in the afterglow of pulsed discharges by absorption spectroscopy with light emitting diodes: application to BCl radical Appl. Phys. Lett. 94 021504
71. Cunge G, Vempaire D, Ramos R, Touzeau M, Joubert O, Bodard P and Sadeghi N 2010 Radical surface interactions in industrial silicon plasma etch reactors Plasma Sources Sci. Technol. 19 034017
72. Kono A, Haverlag M, Kroesen G M W and de Hoog F J 1991 Temporal behavior of the electron and negative ion densities in a pulsed radio frequency CF4 plasma J. Appl. Phys. 70 2930
73. Bodart P, Brihoum M, Cunge G, Joubert O and Sadeghi N 2011 Analysis of pulsed high-density HBr and Cl2 plasmas: impact of the pulsing parameters on the radical densities J. Appl. Phys. 110 113302
74. Hargis P J et al 1994 The gaseous electronics conference radio-frequency reference cell: a defined parallel-plate radio-frequency system for experimental and theoretical studies of plasma-processing discharges Rev. Sci. Instrum. 65 140
75. Miller P A, Hebner G A, Pochan P D, Greenberg K E and Aragon B P 1995 An inductively coupled plasma source for the gaseous electronics conference rf reference cell J. Res. Natl Inst. Stand. Technol. 100 427
76. Ramamurthi B and Economou D J 2002 Two-dimensional pulsed-plasma simulation of a chlorine discharge J. Vac. Sci. Technol. A 20 467 (Pubitemid 34405116)
77. Agarwal A, Stout P J, Banna S, Rauf S and Collins K 2011 Recouping etch rates in pulsed inductively coupled plasmas J. Vac. Sci. Technol. A 29 011017
78. Wagner J A and Katsch H-M 2006 Negative oxygen ions in a pulsed RF-discharge with inductive coupling in mixtures of noble gases and oxygen Plasma Sources Sci. Technol. 15 156 (Pubitemid 43254139)
79. Hayashi D and Kadota K 1998 Measurements of negative ion density in high-density oxygen plasmas by probe-assisted laser photodetachment J. Appl. Phys. 83 697
80. Panda S, Economou D J and Meyyappan M 2000 Effect of metastable oxygen molecules in high-density power modulated oxygen discharges J. Appl. Phys. 87 8323
81. Ashida S, Lee C and Lieberman M A 1995 Spatially averaged (global) model of time modulated high density argon plasmas J. Vac. Sci. Technol. A 13 2498
82. Yokozawa A, Ohtake H and Samukawa S 1996 Simulation of pulse time-modulated bulk plasma in Cl2 Japan. J. Appl. Phys. 35 2433
83. Lee C, Graves D B, Lieberman M A and Hess D W 1994 Global model of plasma chemistry in a high density oxygen discharge J. Electrochem. Soc. 141 1546
84. Hopkins M B and Graham W G 1991 Time-resolved electron energy distribution function measurements in a pulsed magnetic multipole hydrogen discharge J. Appl. Phys. 69 3461
85. Béchu S, Soum-Glaude A, Bès A, Lacoste A, Svarnas P, Aleiferis S, Ivanov A A Jr and Bacal M 2013 Multi-dipolar microwave plasmas and their application to negative ion production Phys. Plasmas 20 101601
86. Monahan D D and Turner M M 2008 Global models of electronegative discharges: critical evaluation and practical recommendations Plasma Sources Sci. Technol. 17 045003
87. Samukawa S, Sakamoto K and Ichiki K 2001 Generating high-efficiency neutral beams by using negative ions in an inductively coupled plasma source Japan. J. Appl. Phys. Part 2 40 L779
88. Panda S, Economou D J and Chen L 2001 Anisotropic etching of polymer films by high energy (∼100s of eV) oxygen atom neutral beams J. Vac. Sci. Technol. A 19 398 (Pubitemid 32394410)
89. Kanakasabapathy S K, Overzet L J, Midha V and Economou D J 2001 Alternating fluxes of positive and negative ions from an ion-ion plasma Appl. Phys. Lett. 78 22 (Pubitemid 33661744)
90. Kaganovich I, Ramamurthi D B and Economou D J 2000 Self-trapping of negative ions due to electron detachment in the afterglow of electronegative gas plasmas Appl. Phys. Lett. 76 2844
91. Overzet L J, Smith B A, Kleber J and Kanakasabapathy S K 1997 Negative ion extraction from pulsed discharges Japan. J. Appl. Phys. 36 2443
92. Maeshige K, Washio G, Yagisawa T and Makabe T 2002 Functional design of a pulsed two-frequency capacitively coupled plasma in CF4/Ar for SiO2 etching J. Appl. Phys. 91 9494 (Pubitemid 34720068)
93. Yagisawa T and Makabe T 2003 Temporal velocity distribution of positive and negative ions incident on a wafer in a pulsed two-frequency capacitively coupled plasma in CF4/Ar for SiO2 etching IEEE Trans. Plasma Sci. 31 521
94. Agarwal A, Stout P J, Banna S, Rauf S, Tokashiki K, Lee J-Y and Collins K 2009 Effect of simultaneous source and bias pulsing in inductively coupled plasma etching J. Appl. Phys. 106 103305
95. Subramonium P and Kushner M J 2004 Extraction of negative ions from pulsed electronegative inductively coupled plasmas having a radio frequency substrate bias J. Vac. Sci. Technol. A 22 534
96. Riemann K-U 2003 Kinetic analysis of the collisional plasma-sheath transition J. Phys. D: Appl. Phys. 36 2811
97. Kortshagen U and Zethoff M 1995 Ion energy distribution functions in a planar inductively coupled RF discharge Plasma Sources Sci. Technol. 4 541
98. Aydil E S, Quiniou B O M, Lee J T C, Gregus J A and Gottscho R A 1998 Incidence angle distributions of ions bombarding grounded surfaces in high density plasma reactors Mater. Sci. Semicond. Process. 1 75
99. Diomede P, Longo S, Economou D J and Capitelli M 2012 Hybrid simulation of a dc-enhanced radio-frequency capacitive discharge in hydrogen J. Phys. D: Appl. Phys. 45 175204
100. Nam S K, Economou D J and Donnelly V M 2007 Particle-in-cell simulation of ion beam extraction from a pulsed plasma through a grid Plasma Sources Sci. Technol. 16 90
101. Smith B A and Overzet L J 1995 Time-resolved energy distributions of F- from pulsed radio frequency discharges J. Appl. Phys. 78 5195
102. Coburn J W and Kay E 1972 Positive-ion bombardment of substrates in rf diode glow discharge sputtering J. Appl. Phys. 43 4965
103. Diomede P, Donnelly V M and Economou D J 2011 Particle-in-cell simulation of ion energy distributions on an electrode by applying tailored bias waveforms in the afterglow of a pulsed plasma J. Appl. Phys. 109 083302
104. Diomede P, Kim D and Economou D J 2013 Particle-in-cell simulation of electron and ion energy distributions in dc/RF hybrid capacitively-coupled plasmas AIChE J. 59 3214
105. Godyak V A, Piejak R B and Alexandrovich B M 1992 Measurement of electron energy distribution in low-pressure RF discharges Plasma Sources Sci. Technol. 1 36
106. Sugai H, Ghanashev I, Hosokawa M, Mizuno K, Nakamura K, Toyoda H and Yamauch K 2001 Electron energy distribution functions and the influence on fluorocarbon plasma chemistry Plasma Sources Sci. Technol. 10 378 (Pubitemid 32534433)
107. Song S-H and Kushner M J 2012 Control of electron energy distributions and plasma characteristics of dual frequency, pulsed capacitively-coupled plasmas sustained in Ar and Ar/CF4/O2 Plasma Sources Sci. Technol. 21 055028
108. Sun J, Li X, Sang C, Jiang W, Zhang P and Wang D 2010 Particle-in-cell simulation of hydrogen discharge driven by combined radio frequency and pulse sources Phys. Plasmas 17 103505
109. Gozadinos G, Vender D, Turner M M and Lieberman M A 2001 Collisionless electron heating by capacitive radio-frequency plasma sheaths Plasma Sources Sci. Technol. 10 117 (Pubitemid 32534407)
110. Boswell R W and Henry D 1985 Pulsed high rate plasma etching with variable Si/SiO2 selectivity and variable Si etch profiles Appl. Phys. Lett. 47 1095
111. Samukawa S and Furuoya S 1993 Time-modulated electron cyclotron resonance discharge for controlling generation of reactive species Appl. Phys. Lett. 63 2044
112. Petit-Etienne C, Darnon M, Bodart P, Fouchier M, Cunge G, Pargon E, Vallier L and Joubert O 2013 Atomic scale silicon etching control using pulsed plasma J. Vac. Sci. Technol. B 31 011201
113. Athavale S and Economou D J 1996 Realization of atomic layer etching (ALET) of silicon J. Vac. Sci. Technol. B 14 3702
114. Athavale S D and Economou D J 1995 Molecular dynamics simulation of atomic layer etching (ALET) of silicon J. Vac. Sci. Technol. A 13 966
115. Donnelly V M and Economou D J 2009 Atomic layer etching with pulsed plasmas US and International Patents Provisional patent application No. 61/286, 572
116. Hwang G S and Giapis K P 1998 Mechanism of charging reduction in pulsed plasma etching Japan J. Appl. Phys. 37 2291
117. Ishikawa Y, Ichihashi Y, Yamasaki S and Samukawa S 2008 UV photon-induced defect and its control in plasma etching processes J. Appl. Phys. 104 063306
118. Ono K and Tuda M 2000 Dynamics of plasma-surface interactions and feature profile evolution during pulsed plasma etching Thin Solid Films 374 208 (Pubitemid 32030455)
119. Schaepkens M, Oehrlein G S and Cook J M 2000 Effects of radio frequency bias frequency and radio frequency bias pulsing on SiO2 feature etching in inductively coupled fluorocarbon plasma J. Vac. Sci. Technol. B 18 856
120. Raballand V, Cartry G and Cardinaud C 2007 Porous SiOCH, SiCH and SiO2 etching in high density fluorocarbon plasma with a pulsed bias Plasma Process. Polym. 4 563 (Pubitemid 47181077)
121. Banna S et al 2009 Inductively coupled pulsed plasmas in the presence of synchronous pulsed substrate bias for robust, reliable, fine conductor etching IEEE Trans. Plasma Sci. 37 1730
122. Cicala G 2012 Deposition of carbon based materials by continuous and pulsed discharges Surf. Eng. 28 141
123. Winder E J and Gleason K K 2000 Growth and characterization of fluorocarbon thin films grown from trifluoromethane (CHF3) using pulsed-plasma enhanced CVD J. Appl. Polym. Sci. 78 842
124. Pedersen H, Larsson P, Aijaz A, Jensen J and Lundin D 2012 A novel high-power pulse PECVD method Surf. Coat. Technol. 206 4562
125. Agarwal A and Kushner M J 2009 Plasma atomic layer etching using conventional plasma equipment J. Vac. Sci. Technol. A 27 37
126. Park S-D, Min K-S, Yoon B-Y, Lee D-H and Yeom G-Y 2005 Precise depth control of silicon etching using chlorine atomic layer etching Japan. J. Appl. Phys. 44 389 (Pubitemid 40401573)
127. Park S D, Oh C K, Lee D H and Yeom G Y 2005 Surface roughness variation during Si atomic layer etching by chlorine adsorption followed by an Ar neutral beam irradiation Electrochem. Solid State Lett. 8 C177 (Pubitemid 41609813)
128. Metzler D, Bruce R L, Engelmann S, Joseph E A and Oehrlein G S 2014 Fluorocarbon assisted atomic layer etching of SiO2 using cyclic Ar/C4F8 plasma J. Vac. Sci. Technol. A 32 020603
129. Economou D J 2008 Fast (10s-100s eV) neutral beams for materials processing J. Phys. D: Appl. Phys. 41 024001
130. Ranjan A, Donnelly V M and Economou D J 2006 Energy distribution and flux of fast neutrals and residual ions extracted from a neutral beam source J. Vac. Sci. Technol. A 24 1839 (Pubitemid 44370774)
131. Todorow V, Holland J and Gani N 2004 US Patent 6818562
132. Chen J-Y, Holland J P, Sato A H and Todorow V N 2002 US Patent 6472822
133. Banna S, Todorow V and Ramaswamy K 2009 US Patent 0284156 A1
134. unpublished