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Title: Disilane as a growth rate catalyst of plasma deposited microcrystalline silicon thin films

Abstract

The effect of small disilane addition on the gas phase properties of silane-hydrogen plasmas and the microcrystalline silicon thin films growth is presented. The investigation was conducted in the high pressure regime and for constant power dissipation in the discharge with the support of plasma diagnostics, thin film studies and calculations of discharge microscopic parameters and gas dissociation rates. The experimental data and the calculations show a strong effect of disilane on the electrical properties of the discharge in the pressure window from 2 to 3 Torr that is followed by significant raise of the electron number density and the drop of the sheaths electric field intensity. Deposition rate measurements show an important four to six times increase even for disilane mole fractions as low as 0.3 %. The deposition rate enhancement was followed by a drop of the material crystalline volume fraction but films with crystallinity above 40 % were deposited with different combinations of total gas pressure, disilane and silane molar ratios. The enhancement was partly explained by the increase of the electron impact dissociation rate of silane which rises by 40% even for 0.1% disilane mole fraction. The calculations of the gas usage, the dissociation and themore » deposition efficiencies show that the beneficial effect on the growth rate is not just the result of the increase of Si-containing molecules density but significant changes on the species participating to the deposition and the mechanism of the film growth are caused by the disilane addition. The enhanced participation of the highly sticking to the surface radical such as disilylene, which is the main product of disilane dissociation, was considered as the most probable reason for the significant raise of the deposition efficiency. The catalytic effect of such type of radical on the surface reactivity of species with lower sticking probability is further discussed, while it is also used to explain the restricted and sensitive process window where the disilane effect appears.« less

Authors:
; ;  [1];  [2];  [3]; ; ;  [4]
  1. Department of Chemical Engineering, Plasma Technology Laboratory, University of Patras, P.O. Box 140, 26504 Patras (Greece)
  2. University of Ioannina, Dep. of Chemistry, 45110, Ioannina (Greece)
  3. Department of Physics, University of Patras, P.O. Box 140, 26504 Patras (Greece)
  4. Air Liquide CRCD,1 chemin de la porte des Loges, Les Loges en Josas, 78354 Jouy en Josas (France)
Publication Date:
OSTI Identifier:
22611477
Resource Type:
Journal Article
Resource Relation:
Journal Name: AIP Advances; Journal Volume: 6; Journal Issue: 7; Other Information: (c) 2016 Author(s); Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; CATALYSTS; CRYSTAL GROWTH; DENSITY; DEPOSITION; DISSOCIATION; EFFICIENCY; ELECTRIC FIELDS; HYDROGEN; MOLECULES; PLASMA DIAGNOSTICS; REACTIVITY; SILANES; SILICON; SURFACES; THIN FILMS

Citation Formats

Dimitrakellis, P., Amanatides, E., E-mail: lef@plasmatech.gr, Mataras, D., Kalampounias, A. G., Spiliopoulos, N., Lahootun, V., Coeuret, F., and Madec, A. Disilane as a growth rate catalyst of plasma deposited microcrystalline silicon thin films. United States: N. p., 2016. Web. doi:10.1063/1.4958918.
Dimitrakellis, P., Amanatides, E., E-mail: lef@plasmatech.gr, Mataras, D., Kalampounias, A. G., Spiliopoulos, N., Lahootun, V., Coeuret, F., & Madec, A. Disilane as a growth rate catalyst of plasma deposited microcrystalline silicon thin films. United States. doi:10.1063/1.4958918.
Dimitrakellis, P., Amanatides, E., E-mail: lef@plasmatech.gr, Mataras, D., Kalampounias, A. G., Spiliopoulos, N., Lahootun, V., Coeuret, F., and Madec, A. Fri . "Disilane as a growth rate catalyst of plasma deposited microcrystalline silicon thin films". United States. doi:10.1063/1.4958918.
@article{osti_22611477,
title = {Disilane as a growth rate catalyst of plasma deposited microcrystalline silicon thin films},
author = {Dimitrakellis, P. and Amanatides, E., E-mail: lef@plasmatech.gr and Mataras, D. and Kalampounias, A. G. and Spiliopoulos, N. and Lahootun, V. and Coeuret, F. and Madec, A.},
abstractNote = {The effect of small disilane addition on the gas phase properties of silane-hydrogen plasmas and the microcrystalline silicon thin films growth is presented. The investigation was conducted in the high pressure regime and for constant power dissipation in the discharge with the support of plasma diagnostics, thin film studies and calculations of discharge microscopic parameters and gas dissociation rates. The experimental data and the calculations show a strong effect of disilane on the electrical properties of the discharge in the pressure window from 2 to 3 Torr that is followed by significant raise of the electron number density and the drop of the sheaths electric field intensity. Deposition rate measurements show an important four to six times increase even for disilane mole fractions as low as 0.3 %. The deposition rate enhancement was followed by a drop of the material crystalline volume fraction but films with crystallinity above 40 % were deposited with different combinations of total gas pressure, disilane and silane molar ratios. The enhancement was partly explained by the increase of the electron impact dissociation rate of silane which rises by 40% even for 0.1% disilane mole fraction. The calculations of the gas usage, the dissociation and the deposition efficiencies show that the beneficial effect on the growth rate is not just the result of the increase of Si-containing molecules density but significant changes on the species participating to the deposition and the mechanism of the film growth are caused by the disilane addition. The enhanced participation of the highly sticking to the surface radical such as disilylene, which is the main product of disilane dissociation, was considered as the most probable reason for the significant raise of the deposition efficiency. The catalytic effect of such type of radical on the surface reactivity of species with lower sticking probability is further discussed, while it is also used to explain the restricted and sensitive process window where the disilane effect appears.},
doi = {10.1063/1.4958918},
journal = {AIP Advances},
number = 7,
volume = 6,
place = {United States},
year = {Fri Jul 15 00:00:00 EDT 2016},
month = {Fri Jul 15 00:00:00 EDT 2016}
}
  • Microcrystalline silicon thin film is deposited under different conditions by plasma enhanced chemical vapor deposition. The light stability with different crystallinity and grain size is studied, and the growth mechanism is analyzed using the scaling behavior of roughening surface evolution. Degradation of photoconductivity mainly depends on crystallinity and grain size, but fundamentally, on the growth mechanism. Materials with high crystallinity and large grain size are more stable under light soaking. With the increasing of deposition pressure and input power, growth process transfers to zero diffusion limit growth mechanism, and films deposited present less grain size and poor light stability. (author)
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