Chemistry Reference
In-Depth Information
TABLE 8.14
Properties of Plasma Polymers
Properties
Mechanical
Crystallinity
Amorphous
Density
∼
1 g/cm
3
Hardness
Scratch resistant coating
SiO
2
:H
Microhardness 5-10GPa
a-C:H
Microhardness
>
20GPa [310]
Permeability
Semipermeable membranes
Internal stress
≤
10
8
N/m
2
[309]
Adhesion on substrate
Good for thin films
Thermal stability
Good
Pinhole density
Pinhole free
Corrosion protection
Thickness
<
1 μm
Deposition rate
∼
10nm/min
Chemical
Chemical composition
Specific gas permeability for
different gases
Semipermeable membranes
Cross linking
High: low solubility, chemical
inertness
Corrosion protection
10
18
−
10
20
spins/g: aging effects
Radical concentration
Surface chemistry
Surface energy, high : hydrophilic
wettable, low: hydrophobic
Coating of textiles
Optical properties
Transparency
Refractive index 500nm for
various precursors [310]
1.35-1.38 C
2
F
4
,C
4
F
8
, etc.
Antireflection coating
1.41-1.47 tetraethoxysilane
1.47-1.50 hexamethyldisiloxane
1.75 hexamethyldisilazane
Dielectric properties
Application in microelectronics
Dielectric permittivity ε
2.5-5.23 [146]
Loss angle: tang δ
5
·
10
−
4
−
10
−
2
[146]
Electric strength [V/cm]
5-12
·
10
6
[311]
Conductivity [1/
cm]
3
·
10
−
18
−
1.8
·
10
−
13
[146]
Conductivity change by adsorbed
gases
Gas sensors [146]
deposited film. The formation of activated species in the plasma is determined directly
or indirectly (formation of metastable atoms) by collisions of monomer molecules
with electrons. The products are excited particles, ions, or neutral radicals generated
in dissociative collisions. Reactive species with a single reactive site and also divalent
reactive species are possible [305]. According to the essentially higher concentration
of neutral radicals in relation to the ions, these neutral species may be accountably for
