Chemistry Reference
In-Depth Information
organosilicon monomers like hexamethyldisiloxane were used in the deposition
experiments. Ar is admixed for metal sputtering. Plasma sources as magnetrons
and capacitively coupled rf discharges were applied as reactors.
Deposition of polysiloxane thin films containing Ag particles is reported by
[362]. A combination of silver sputtering and plasma polymerization of HMDSO
is applied. An asymmetrical rf (13.56 MHz) discharge was used with an Ag tar-
get at the powered electrode operating in an Ar (
p
Ar
=
5.32 Pa) and pulsating
HMDSO flow (
p
HMDSO
1.06 Pa). Pulsation of the HMDSO flow varies
the cathode coverage with polymer deposit. Energetic ion bombardment of the
powered electrode sputters plasma polymer deposit and silver. A composite of
polymer and silver is deposited on the substrate. Ag volume fraction near 50% is
observed for low HMDSO flow rates; high flow rates show a disappearing Ag frac-
tion. Small spherical metal grains (diameter between 2 and 10 nm) are observed for
low-volume fractions (0.25); higher factions show nonspherical Ag clusters of 30-
100 nm separated by thin polymer domains (see Figure 8.52). Such silver-containing
materials are important for biomedical applications, e.g., for prevention of biofilm
formation.
ThedepositionofPt-containingcompositefilmsusingC
2
H
4
/Armixture(
=
0.27
−
1:100)
inaasymmetriccapacitivelycoupled13.56 MHzdischargeat 70 mTorr is investigated
by Dilonardo [361]. The Pt target is positioned at the small powered electrode, the
composite film growth on a polished Si-substrate on the grounded electrode. The Pt-
atomic concentration increases with discharge power, but decreases with increasing
C
2
H
4
flow rate. The Pt-content can be continuously varied between
∼
∼
100% and
∼
0% by the deposition conditions. The nanocrystalline clusters are embedded in the
polymer matrix; their size varies with the Pt-content.
200 nm
FIGURE 8.52
Large nonspherical silver clusters in an HMDSO-plasma polymer matrix.
(From Despax, B. and Raynaud, P.,
Plasma Process. Polym.
, 4, 127, 2007.)
