Spectroscopic diagnostics and modelling of silane microwave plasmas

Low-pressure silane plasmas (2-20 Pa) diluted with the noble gases helium and argon as well as hydrogen were generated by microwave excitation in order to determine plasma parameters and absolute particle number densities. Specific silane radicals (SiH, Si, , H) were measured by means of optical emission spectroscopy, whereas particle densities of silane, disilane and molecular hydrogen were measured with mass spectroscopy. Experimental results confirm model calculations, which were carried out to determine number densities of all silane radicals and of higher silanes as well as electron temperature. The electron temperature varies from 1.5 to 4 eV depending on pressure and gas mixture. The temperature of heavy particles is 450 K and the electron number density is . The rotational temperatures of SiH are between room temperature and 2000 K due to increasing dissociative excitation. In the plasma the number density of silane is reduced, whereas the number density of molecular hydrogen is close to the silane density, which is fed in. Particle densities of , disilane and atomic hydrogen are in the range of a few per cent of the silane number density. At low pressure the density is similar to and decreases with increasing pressure due to heavy particle collisions with silane producing higher silanes. Particle densities of SiH and Si are only in the range of some of the silane density decreasing with increasing collisions of heavy particles with silane and molecular hydrogen. In mixtures with argon Penning reactions increase the silane dissociation.

[1]  J. Perrin,et al.  Growth of hydrogenated amorphous silicon due to controlled ion bombardment from a pure silane plasma , 1983 .

[2]  I. Kovacs,et al.  Rotational structure of the spectra of diatomic molecules , 1972 .

[3]  L. C. Johnson,et al.  Ionization, recombination, and population of excited levels in hydrogen plasmas. , 1973 .

[4]  J. Perrin,et al.  Spatially resolved optical emission and electrical properties of SiH4 RF discharges at 13.56 MHz in a symmetric parallel-plate configuration , 1991 .

[5]  K. Behringer.  Diagnostics and modelling of ECRH microwave discharges , 1991 .

[6]  H. Yoshida,et al.  Cross sections for deexcitation of He(2 3S, 2 1S and 2 1P) by SiH4 and GeH4 , 1991 .

[7]  W. Breiland,et al.  Laser studies of the reactivity of SiH with the surface of a depositing film , 1989 .

[8]  G. Turban,et al.  Mass spectrometric study of SF6-N2 plasma during etching of silicon and tungsten , 1990 .

[9]  J. Loureiro,et al.  Characteristics of high-frequency and direct-current argon discharges at low pressures: a comparative analysis , 1984 .

[10]  M. Tsuji,et al.  Dissociative excitation of SiH4 by collisions with metastable argon atoms , 1989 .

[11]  R. Wilhelm,et al.  Elongated microwave electron cyclotron resonance heating plasma source , 1990 .

[12]  H. Summers,et al.  The Recombination and Level Populations of Ions—I HYDROGEN AND HYDROGENIC IONS , 1976 .

[13]  R. Anderson,et al.  Electron excitation of the singlet‐g states of H2 , 1979 .

[14]  G. Bruno,et al.  Time-resolved optical emission spectroscopy of modulated plasmas for amorphous silicon deposition , 1992 .

[15]  G. Möhlmann,et al.  Emission cross sections of balmer-α,β,γ radiation for electrons (0–2000 eV) on H2 and D2 , 1977 .

[16]  A. Matsuda,et al.  Lifetime of dominant radicals for the deposition of a-Si:H from SiH4 and Si2H6 glow discharges , 1983 .

[17]  M. Kushner.  Simulation of the gas‐phase processes in remote‐plasma‐activated chemical‐vapor deposition of silicon dielectrics using rare gas–silane‐ammonia mixtures , 1992 .

[18]  J. Perrin,et al.  Silane dissociation mechanisms and thin film formation in a low pressure multipole dc discharge , 1980 .

[19]  A. Gallagher,et al.  Silane dissociation products in deposition discharges , 1990 .

[20]  P. Haaland.  Dissociative ionization of silane , 1990 .

[21]  J. Perrin,et al.  Dissociation cross sections of silane and disilane by electron impact , 1982 .

[22]  Toshihiko Satō,et al.  Level excitation cross sections of Si I fragments produced by 100 eV electron impact on SiH4 , 1988 .

[23]  T. Fujimoto.  A collisional-radiative model for helium and its application to a discharge plasma , 1979 .

[24]  F. Kampas,et al.  Origin of emitting species in the plasma deposition of a‐Si:H alloys , 1981 .

[25]  P. Armentrout,et al.  Kinetic energy dependence of dissociative charge-transfer reactions of He+, Ne+, Ar+, Kr+, and Xe+ with silane , 1990 .

[26]  J. Perrin,et al.  Production mechanism and reactivity of the SiH radical in a silane plasma , 1984 .

[27]  J. Perrin,et al.  Mass spectrometry detection of radicals in SiH4-CH4-H2 glow discharge plasmas , 1995 .

[28]  J. Perrin,et al.  Surface recombination probabilities of H on stainless steel, a-Si:H and oxidized silicon determined by threshold ionization mass spectrometry in H2 RF discharges , 1996 .

[29]  J. Perrin,et al.  Emission spectroscopy of SiH in a silane glow-discharge , 1980 .

[30]  A. Gallagher,et al.  Plasma chemistry in silane/germane and disilane/germane mixtures , 1992 .

[31]  J. Perrin.  Modelling of the power dissipation and rovibrational heating and cooling in SiH4-H2 RF glow discharges , 1993 .

[32]  W. L. Borst.  Excitation of metastable argon and helium atoms by electron impact , 1974 .

[33]  M. Stamp,et al.  REVIEW ARTICLE: Spectroscopic determination of impurity influx from localized surfaces , 1989 .

[34]  Yoshiharu Nakamura,et al.  Electron collision cross sections for the monosilane molecule , 1989 .

[35]  Mark J. Kushner,et al.  A model for the discharge kinetics and plasma chemistry during plasma enhanced chemical vapor deposition of amorphous silicon , 1988 .

[36]  W. Möller.  Plasma and surface modeling of the deposition of hydrogenated carbon films from low-pressure methane plasmas , 1993 .

[37]  G. Möhlmann,et al.  Emission cross sections of the H2(3p3Πu→2s3Σ+g transition for electron impact on H2 , 1976 .

[38]  J. Perrin,et al.  Temperature dependence of the sticking and loss probabilities of silyl radicals on hydrogenated amorphous silicon , 1990 .

[39]  R. Robertson,et al.  Total and partial electron collisional ionization cross sections for CH4, C2H6, SiH4, and Si2H6 , 1984 .

[40]  M. Gordon.  Structure and stability of SiH+4☆ , 1978 .

[41]  Mark J. Kushner,et al.  On the balance between silylene and silyl radicals in rf glow discharges in silane: The effect on deposition rates of a‐Si:H , 1987 .

[42]  Frank J. Kampas,et al.  An optical emission study of the glow-discharge deposition of hydrogenated amorphous silicon from argon-silane mixtures , 1983 .

[43]  J. Perrin,et al.  Emission cross sections from fragments produced by electron impact on silane , 1982 .

[44]  G. Turban,et al.  Ion and radical reactions in the silane glow discharge deposition of a-Si:H films , 1982 .

[45]  O. Leroy,et al.  Cross-Sections, Rate Constants and Transport Coefficients in Silane Plasma Chemistry , 1996 .

[46]  Toshihiko Satō,et al.  Emission Cross Sections of Excited Fragments Produced by 0-100 eV Electron Impact on SiH4: Application of the “He Standard” , 1986 .

[47]  D. C. Cartwright,et al.  Electron-impact excitation of electronic states in argon at incident energies between 16 and 100 eV , 1981 .

[48]  F. Kampas.  Gas‐phase free radical reactions in the glow‐discharge deposition of hydrogenated amorphous silicon from silane and disilane , 1985 .

[49]  J. Jasinski,et al.  Absolute rate constants for the reaction of silylene with hydrogen, silane, and disilane , 1988 .

[50]  R. Robertson,et al.  Radical species in argon‐silane discharges , 1983 .

[51]  K. Tachibana,et al.  Measurement of Absolute Densities and Spatial Distributions of Si and SiH in an RF-Discharge Silane Plasma for the Chemical Vapor Deposition of a-Si:H Films , 1991 .

[52]  A. Gallagher,et al.  Surface reaction probability of film‐producing radicals in silane glow discharges , 1990 .

[53]  U. Fantz,et al.  Spectroscopic diagnostics of glow discharge plasmas with non-Maxwellian electron energy distributions , 1994 .

[54]  Makoto Suzuki,et al.  Reactions of SiH2(X̄1A1) with H2, CH4, C2H4, SiH4 and Si2H6 at 298 K , 1985 .

[55]  I. Dubois.  The absorption spectrum of the free SiH2 radical , 1968 .

[56]  S. Vepřek,et al.  Dominant reaction channels and the mechanism of silane decomposition in a H2-Si(s)-SiH4 glow discharge , 1987 .

[57]  W. Lotz,et al.  An empirical formula for the electron-impact ionization cross-section , 1966 .

[58]  Gallagher,et al.  Causes of SiH4 dissociation in silane dc discharges. , 1990, Physical review. A, Atomic, molecular, and optical physics.

[59]  F. Pool,et al.  Electron cyclotron resonance deposition of a-Si:H and a-C:H films , 1989 .

[60]  M. Heintze,et al.  The mechanism of plasma-induced deposition of amorphous silicon from silane , 1990 .

[61]  J. D. Morrison,et al.  Ionization and dissociation by electron impact III. CH4 and SiH4 , 1973 .

[62]  J. Perrin,et al.  Dissociative excitation of SiH4, SiD4, Si2H6 and GeH4 by 0–100 eV electron impact , 1983 .