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Title: Probe diagnostics of argon-oxygen-tetramethyltin capacitively coupled plasmas for the deposition of tin oxide thin films

Abstract

Langmuir probe measurements in nondepositing and depositing rf capacitively coupled (CCP) plasmas are briefly reviewed and compared to the results obtained in our rf system used for the deposition of tin oxide (SnO{sub 2}) thin films from argon-oxygen-tetamethyltin [Sn(CH{sub 3}){sub 4}] plasmas. Typically in our experimental conditions for tin oxide deposition, values of kT{sub eff}= 1.2-1.5 eV and n{sub e}=3-5x10{sup 9} cm{sup -3} were measured. These values are consistent with those generally reported in other depositing discharges. The shape of the electron energy probability function (EEPF), obtained from the Druyvesteyn procedure, was discussed too. As a consequence of the two electron heating mechanisms in capacitively coupled discharges, that is, ohmic and stochastic heating, the electrons have a bi-Maxwellian EEPF at low pressure (in the range of 10-100 mTorr). Moreover, a deep 'hole' appears in the EEPF at the energy which could correspond to the resonant peak of the vibrational excitation cross section of some molecules which can be present in the discharge, such as N{sub 2}, CH{sub 4}, or CO.

Authors:
; ;  [1]
  1. Laboratoire de Genie des procedes Plasmas, Ecole Nationale Superieure de Chimie Paris, Universite Pierre et Marie Curie, Paris 6 (France)
Publication Date:
OSTI Identifier:
20982791
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 101; Journal Issue: 7; Other Information: DOI: 10.1063/1.2561749; (c) 2007 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; ARGON; CARBON MONOXIDE; CHEMICAL VAPOR DEPOSITION; COATINGS; CROSS SECTIONS; ELECTRONS; EV RANGE 01-10; EXCITATION; HEATING; HIGH-FREQUENCY DISCHARGES; LANGMUIR PROBE; METHANE; OXYGEN; PLASMA; PROBABILITY; RF SYSTEMS; STOCHASTIC PROCESSES; THIN FILMS; TIN OXIDES

Citation Formats

Pulpytel, J., Morscheidt, W., and Arefi-Khonsari, F. Probe diagnostics of argon-oxygen-tetramethyltin capacitively coupled plasmas for the deposition of tin oxide thin films. United States: N. p., 2007. Web. doi:10.1063/1.2561749.
Pulpytel, J., Morscheidt, W., & Arefi-Khonsari, F. Probe diagnostics of argon-oxygen-tetramethyltin capacitively coupled plasmas for the deposition of tin oxide thin films. United States. doi:10.1063/1.2561749.
Pulpytel, J., Morscheidt, W., and Arefi-Khonsari, F. Sun . "Probe diagnostics of argon-oxygen-tetramethyltin capacitively coupled plasmas for the deposition of tin oxide thin films". United States. doi:10.1063/1.2561749.
@article{osti_20982791,
title = {Probe diagnostics of argon-oxygen-tetramethyltin capacitively coupled plasmas for the deposition of tin oxide thin films},
author = {Pulpytel, J. and Morscheidt, W. and Arefi-Khonsari, F.},
abstractNote = {Langmuir probe measurements in nondepositing and depositing rf capacitively coupled (CCP) plasmas are briefly reviewed and compared to the results obtained in our rf system used for the deposition of tin oxide (SnO{sub 2}) thin films from argon-oxygen-tetamethyltin [Sn(CH{sub 3}){sub 4}] plasmas. Typically in our experimental conditions for tin oxide deposition, values of kT{sub eff}= 1.2-1.5 eV and n{sub e}=3-5x10{sup 9} cm{sup -3} were measured. These values are consistent with those generally reported in other depositing discharges. The shape of the electron energy probability function (EEPF), obtained from the Druyvesteyn procedure, was discussed too. As a consequence of the two electron heating mechanisms in capacitively coupled discharges, that is, ohmic and stochastic heating, the electrons have a bi-Maxwellian EEPF at low pressure (in the range of 10-100 mTorr). Moreover, a deep 'hole' appears in the EEPF at the energy which could correspond to the resonant peak of the vibrational excitation cross section of some molecules which can be present in the discharge, such as N{sub 2}, CH{sub 4}, or CO.},
doi = {10.1063/1.2561749},
journal = {Journal of Applied Physics},
number = 7,
volume = 101,
place = {United States},
year = {Sun Apr 01 00:00:00 EDT 2007},
month = {Sun Apr 01 00:00:00 EDT 2007}
}
  • The kinetics of the chemical vapor deposition of tin oxide films from tetramethyltin (TMT) and oxygen are determined. This proposed mechanism, which reproduces the results of Borman and Gordon, is a branched chain process with a key intermediate of (CH{sub 3}){sub 3}SnOH whose decomposition and oxidation leads to film growth and release of hydrocarbons. The modeling in this paper indicates that the rate-limiting steps occur in the gas phase, and the gas-phase oxidation of TMT has different pathways than neopentane. 91 refs., 9 figs., 5 tabs.
  • The piezoresistivity of thin films of indium tin oxide prepared by pulsed laser deposition has been measured as a function of the O-to-(In+Sn) atom ratio. The oxygen-to-metal atom ratio was determined through Rutherford backscattering spectrometry and x-ray photoelectron spectroscopy analyses. Gauge factors, defined as the fractional change of the film resistance to the applied strain, increase with the film's oxygen content. The deposition under 50 mTorr oxygen pressure resulted in the film with the largest oxygen-to-metal atom ratio, 1.92, and a gauge factor of -14.5. A model based on hopping conduction is proposed. Results from this model are consistent withmore » the sign and magnitude of the observed gauge factors.« less
  • An tunable diode laser absorption spectroscopy has been used to determine the Ar*({sup 3}P{sub 2}) and Ar*({sup 3}P{sub 0}) metastable atoms densities in dual-frequency capacitively coupled plasmas. The effects of different control parameters, such as high-frequency power, gas pressure and content of Ar, on the densities of two metastable atoms and electron density were discussed in single-frequency and dual-frequency Ar discharges, respectively. Particularly, the effects of the pressure on the axial profile of the electron and Ar metastable state densities were also discussed. Furthermore, a simple rate model was employed and its results were compared with experiments to analyze themore » main production and loss processes of Ar metastable states. It is found that Ar metastable state is mainly produced by electron impact excitation from the ground state, and decayed by diffusion and collision quenching with electrons and neutral molecules. Besides, the addition of CF{sub 4} was found to significantly increase the metastable destruction rate by the CF{sub 4} quenching, especially for large CF{sub 4} content and high pressure, it becomes the dominant depopulation process.« less
  • Tin oxide films doped with fluorine or antimony are transparent conductors used in optoelectronic devices and solar cells. Silicon oxide thin films are used as diffusion barriers, passivation layers and dielectric layers in the microelectronics industry. Tin oxide thin films are commonly deposited in atmospheric pressure chemical vapor deposition (APCVD) processes by hydrolyzing SnCl[sub 4] or by reacting tetramethyltin with oxygen. The APCVD of silicon oxide films normally involves the reaction of ozone or oxygen with SiH[sub 4] or tetraethylorthosilicate. Gordon et al. recently reported the use of main-group amido complexes and ammonia as precursors in the APCVD of main-groupmore » nitride thin films. Because the amido precursors are volatile, easily synthesized, and relatively safe to handle, the authors decided to examine their use as precursors to main-group oxide thin films. This paper reports the successful APCVD of tin and silicon oxide from homoleptic dimethylamido complexes, M(NMe[sub 2])[sub 4] (M = Sn, Si), and oxygen at deposition temperatures ranging from 250 to 400[degrees]C. 14 refs., 2 figs., 1 tab.« less
  • Measurements with a rf compensated Langmuir probe and optical emission spectroscopy are carried out in capacitively coupled rf (13.56 MHz) pure nitrogen N{sub 2} discharges at fixed rf voltage over a wide range of pressure, 30 to 400 mTorr. The electron energy probability function (EEPF) measured below 100 mTorr resembles a bi-Maxwellian-type distribution. At pressure range of 100-200 mTorr, the EEPF has non-Maxwellian distribution with a ''dip'' near 4.5 eV. At the highest pressure of 400 mTorr, the EEPF evolves into a Druyvestein-like distribution and the ''dip'' disappears. The electron density significantly decreases with increase in the N{sub 2} pressure.more » On the other hand, the electron temperatures gradually decrease with an increase in N{sub 2} pressure, reaching minimum at 150 mTorr, beyond which it abruptly increases. Such evolution of the EEPFs shape with gas pressure has been discussed in terms of non-local electron kinetics and heating mode transition. The emission intensities of nitrogen (0-0) band of second positive system at 337.1 nm and (0-0) band of first negative systems at 391.4 nm are used to determine the dependence of their radiative states N{sub 2}(C{sup 3}{Pi}{sub u}) and N{sub 2}{sup +}(B{sup 2}{Sigma}{sub u}{sup +}) with nitrogen pressure. It is observed that the pressure influences the radiative states differently owing to their different populating mechanisms. The vibrational temperature T{sub {nu}ib} and rotational temperature T{sub rot} are measured for the sequence ({Delta}{nu}=-2) of N{sub 2} second positive system (C{sup 3}{Pi}{yields}B{sup 3}{Pi}{sub g}) using the method of comparing the measured and calculated spectra with a chi-squared minimization procedure. It was found that both T{sub {nu}ib} and T{sub rot} have similar dependences with N{sub 2} pressure; peaked at 100 mTorr beyond which it monotonically decreases with increase in the N{sub 2} pressure. The correlation between the observed maximum value of T{sub {nu}ib} around 100 mTorr and the detected ''dip'' in the EEPF in the same pressure range has been discussed.« less