The formation of cationic silicon clusters SinHm+ by means of ion–molecule reactions in a remote Ar–H2–SiH4 plasma is studied by a combination of ion mass spectrometry and Langmuir probe measurements. The plasma, used for high growth rate deposition of hydrogenated amorphous silicon (a-Si:H), is based on SiH4 dissociation in a downstream region by a thermal plasma source created Ar–H2 plasma. The electron temperature, ion fluence, and most abundant ion emanating from this plasma source are studied as a function of H2 admixture in the source. The electron temperature obtained is in the range of 0.1–0.3 eV and is too low for electron induced ionization. The formation of silicon containing ions is therefore determined by charge transfer reactions between ions emanating from the plasma source and SiH4. While the ion fluence from the source decreases by about a factor of 40 when a considerable flow of H2 is admixed in the source, the flux of cationic silicon clusters towards the substrate depends only slightly on this H2 flow. This implies a strong dissociative recombination of silicon containing ions with electrons in the downstream region for low H2 flows and it causes the distribution of the cationic silicon clusters with respect to the silicon atoms present in the clusters to be rather independent of H2 admixture. The average cluster size increases, however, strongly with the SiH4 flow for constant plasma source properties. Moreover, it leads to a decrease of the ion beam radius and due to this, to an increase of the ion flux towards the substrate, which is positioned in the center of the beam. Assuming unity sticking probability the contribution of the cationic clusters to the total growth flux of the material is about 6% for the condition in which solar grade a-Si:H is deposited. Although the energy flux towards the film by ion bombardment is limited due to the low electron temperature, the clusters have a very compact structure and very low hydrogen content and can consequently have a considerable impact on film quality. The latter is discussed as well as possible implications for other (remote) SiH4 plasmas.

1.
R.
Robertson
and
A.
Gallagher
,
J. Appl. Phys.
59
,
3402
(
1986
).
2.
N.
Itabashi
,
N.
Nishiwaki
,
M.
Magane
,
S.
Naito
,
T.
Goto
,
A.
Matsuda
,
C.
Yamada
, and
E.
Hirota
,
Jpn. J. Appl. Phys., Part 2
29
,
L505
(
1990
).
3.
P.
Kae-Nune
,
J.
Perrin
,
J.
Guillon
, and
J.
Jolly
,
Plasma Sources Sci. Technol.
4
,
250
(
1995
).
4.
A good overview is, e.g., given in
J.
Perrin
,
M.
Shiratani
,
P.
Kae-Nune
,
H.
Videlot
,
J.
Jolly
, and
J.
Guillon
,
J. Vac. Sci. Technol. A
16
,
278
(
1998
).
5.
A.
Matsuda
and
A.
Tanaka
,
J. Appl. Phys.
60
,
2351
(
1986
).
6.
D. A.
Doughty
,
J. R.
Doyle
,
G. H.
Lin
, and
A.
Gallagher
,
J. Appl. Phys.
67
,
6220
(
1990
).
7.
G.
Ganguly
and
A.
Matsuda
,
Phys. Rev. B
47
,
3661
(
1993
).
8.
M. C. M.
van de Sanden
,
R. J.
Severens
,
W. M. M.
Kessels
,
R. F. G.
Meulenbroeks
, and
D. C.
Schram
,
J. Appl. Phys.
84
,
2426
(
1998
).
9.
J.
Perrin
,
Y.
Takeda
,
N.
Hirano
,
H.
Matsuura
, and
A.
Matsuda
,
Jpn. J. Appl. Phys., Part 1
28
,
5
(
1989
).
10.
J. M.
Jasinski
,
J. Vac. Sci. Technol. A
13
,
1935
(
1995
).
11.
A. A.
Howling
,
L.
Sansonnens
,
J.-L.
Dorier
, and
Ch.
Hollenstein
,
J. Appl. Phys.
75
,
1340
(
1994
);
Ch.
Hollenstein
,
A. A.
Howling
,
C.
Courteille
,
D.
Magni
,
S.
Scholz Odermatt
,
G. M. W.
Kroesen
,
N.
Simons
,
W.
de Zeeuw
, and
W.
Schwarzenbach
,
J. Phys. D
31
,
74
(
1998
).
12.
D. M.
Mattox
,
J. Vac. Sci. Technol. A
7
,
1105
(
1989
).
13.
P.
Reinke
,
W.
Jacob
, and
W.
Möller
,
J. Appl. Phys.
74
,
1354
(
1993
).
14.
J. L.
Lee
,
Y. H.
Lee
, and
B.
Farouk
,
J. Appl. Phys.
79
,
7676
(
1996
).
15.
A.
von Keudell
and
W.
Jacob
,
J. Appl. Phys.
81
,
1531
(
1997
).
16.
G.
Ganguly
and
A.
Matsuda
,
Mater. Res. Soc. Symp. Proc.
336
,
7
(
1994
).
17.
K.
Kato
,
S.
Iizuka
,
G.
Ganguly
,
T.
Ikeda
,
A.
Matsuda
, and
N.
Sato
,
Jpn. J. Appl. Phys., Part I
36
,
4547
(
1997
).
18.
E. A. G.
Hamers
,
W. G. J. H. M.
van Sark
,
J.
Bezemer
,
W. F.
van der Weg
, and
W. J.
Goedheer
,
Mater. Res. Soc. Symp. Proc.
420
,
461
(
1996
).
19.
E. A. G.
Hamers
,
W. G. J. H. M.
van Sark
,
J.
Bezemer
,
H.
Meiling
, and
W. F.
van der Weg
,
J. Non-Cryst. Solids
226
,
205
(
1998
).
20.
J. A.
Theil
and
G.
Powell
,
J. Appl. Phys.
75
,
2652
(
1994
).
21.
W. M. M.
Kessels
,
M. C. M.
van de Sanden
, and
D. C.
Schram
,
Appl. Phys. Lett.
72
,
2397
(
1998
).
22.
W. M. M.
Kessels
,
C. M.
Leewis
,
A.
Leroux
,
M. C. M.
van de Sanden
, and
D. C.
Schram
,
J. Vac. Sci. Technol. A
17
,
1531
(
1999
).
23.
R. J. Severens, F. van de Pas, J. Bastiaanssen, W. M. M. Kessels, L. J. van IJzendoorn, M. C. M. van de Sanden, and D. C. Schram, Proceedings of 14th European Photovoltaic Solar Energy Conference and Exhibition, Barcelona, Spain, 1997, p. 582.
24.
W. M. M.
Kessels
,
R. J.
Severens
,
M. C. M.
van de Sanden
, and
D. C.
Schram
,
J. Non-Cryst. Solids
227–230
,
133
(
1998
).
25.
G. J.
Meeusen
,
R. P.
Dahiya
,
M. C. M.
van de Sanden
,
G.
Dinescu
,
Zhou
Qing
,
R. F. G.
Meulenbroeks
, and
D. C.
Schram
,
Plasma Sources Sci. Technol.
3
,
521
(
1994
).
26.
M. C. M.
van de Sanden
et al.,
Surf. Coat. Technol.
74–75
,
1
(
1995
).
27.
J. J.
Beulens
,
M. J.
De Graaf
, and
D. C.
Schram
,
Plasma Sources Sci. Technol.
2
,
180
(
1993
).
28.
M. C. M.
van de Sanden
,
J. M.
de Regt
, and
D. C.
Schram
,
Plasma Sources Sci. Technol.
3
,
501
(
1994
).
29.
M. G. H. Boogaarts, G. J. Brinkman, H. W. P. van de Heijden, P. Vankan, S. Mazouffre, J. A. M. van der Mullen, D. C. Schram, and H. F. Döbele, Proceedings of the Eighth International Symposium, Laser-Aided Plasma Diagnostics, Doorwerth, The Netherlands, 1997, p. 109.
30.
N. Hershkowitz, in Plasma Diagnostics, Vol 1, Discharge Parameters and Chemistry, edited by O. Auciello and D. L. Flamm (Academic, London, 1989), p. 113.
31.
Z.
Qing
,
D. K.
Otorbaev
,
G. J. H.
Brussaard
,
M. C. M.
van de Sanden
, and
D. C.
Schram
,
J. Appl. Phys.
80
,
1312
(
1996
).
32.
E. W.
Peterson
and
L.
Talbot
,
AIAA J.
8
,
2215
(
1970
).
33.
G. J. H. Brussaard, PhD thesis, Eindhoven University of Technology, 1999.
34.
G. J. H.
Brussaard
,
M.
van der Steen
,
M.
Carrère
,
M. C. M.
van de Sanden
, and
D. C.
Schram
,
Phys. Rev. E
54
,
1906
(
1996
).
35.
G. J. H.
Brussaard
,
M. C. M.
van de Sanden
, and
D. C.
Schram
,
Phys. Plasmas
4
,
3077
(
1997
).
36.
E. R.
Mosburg
, Jr.
,
R. C.
Kerns
, and
J. R.
Abelson
,
J. Appl. Phys.
54
,
4916
(
1983
).
37.
R. F. G.
Meulenbroeks
,
P. A. A.
van der Heijden
,
M. C. M.
van de Sanden
, and
D. C.
Schram
,
J. Appl. Phys.
75
,
2775
(
1994
).
38.
G. M. W.
Kroesen
,
D. C.
Schram
,
A. T. M.
Wilbers
, and
G. J.
Meeusen
,
Contrib. Plasma Phys.
31
,
27
(
1991
).
39.
Hiden Analytical Limited, Gemini Business Parc, Warrington WA5 5TN, United Kingdom.
40.
P. H. Dawson, in Quadrupole Mass Spectrometry and its Applications, edited by P. H. Dawson (Elsevier, Amsterdam, 1976).
41.
A. N.
Hayhurst
and
H. R. N.
Jones
,
Int. J. Mass Spectrom. Ion Processes
148
,
L29
(
1995
).
42.
H. Eppler, N. Müller, and G. Rettinghaus, Balzers Instruments, Liechtenstein (private communication).
43.
Ch.
Hollenstein
,
A. A.
Howling
,
C.
Courteille
,
J. L.
Dorier
,
L.
Sansonnens
,
D.
Magni
, and
H.
Müller
,
Mater. Res. Soc. Symp. Proc.
507
,
547
(
1998
).
44.
H. Müller and A. A. Howling (private communication).
45.
A. T. M.
Wilbers
,
G. M. W.
Kroesen
,
C. J.
Timmermans
, and
D. C.
Schram
,
Meas. Sci. Technol.
1
,
1326
(
1990
).
46.
M. C. M.
van de Sanden
,
R.
van den Bercken
, and
D. C.
Schram
,
Plasma Sources Sci. Technol.
3
,
511
(
1994
).
47.
R. F. G.
Meulenbroeks
,
M. F. M.
Steenbakkers
,
Z.
Qing
,
M. C. M.
van de Sanden
, and
D. C.
Schram
,
Phys. Rev. E
49
,
2272
(
1994
).
48.
R. F. G.
Meulenbroeks
,
R. A. H.
Engeln
,
M. N. A.
Beurskens
,
R. M. J.
Paffen
,
M. C. M.
van de Sanden
,
J. A. M.
van de Mullen
, and
D. C.
Schram
,
Plasma Sources Sci. Technol.
4
,
74
(
1995
).
49.
R. F. G.
Meulenbroeks
,
R. A. H.
Engeln
,
J. A. M.
van der Mullen
, and
D. C.
Schram
,
Phys. Rev. E
53
,
5207
(
1996
).
50.
A. J. M.
Buuron
,
K. K.
Otorbaev
,
M. C. M.
van de Sanden
, and
D. C.
Schram
,
Phys. Rev. E
50
,
1383
(
1994
).
51.
J. M. S.
Henis
,
G. W.
Stewart
,
M. K.
Tripodi
, and
P. P.
Gaspar
,
J. Chem. Phys.
57
,
389
(
1972
).
52.
J.
Perrin
,
O.
Leroy
, and
M. C.
Bordage
,
Contrib. Plasma Phys.
36
,
1
(
1996
).
53.
W. D.
Reents
, Jr.
and
M. L.
Mandich
,
Plasma Sources Sci. Technol.
3
,
373
(
1994
).
54.
A. Leroux, W. M. M. Kessels, M. C. M. van de Sanden, and D. C. Schram (unpublished).
55.
It even suggests that clustering reactions are initiated by the same silane ion independent of the ions emanating from the plasma source.
56.
C.
Rebrion-Rowe
,
L.
Lehfaoui
,
B. R.
Rowe
, and
J. B. A.
Mitchell
,
J. Chem. Phys.
108
,
7185
(
1998
).
57.
In fact the ion flux at floating potential has to be considered instead of the ion flux at plasma potential as the substrate is floating. The substrate can however be considered as a planar probe where there is no difference in current at both potentials.
58.
W. M. M.
Kessels
,
M. C. M.
van de Sanden
,
R. J.
Severens
,
L. J.
Van IJzendoorn
, and
D. C.
Schram
,
Mater. Res. Soc. Symp. Proc.
507
,
529
(
1998
).
59.
J. B. Hasted, Physics of Atomic Collisions, 2nd ed. (Butterworths, London, 1972).
60.
K.
Raghavachari
and
V.
Logovinsky
,
Phys. Rev. Lett.
55
,
2853
(
1985
).
This content is only available via PDF.
You do not currently have access to this content.