Chemistry Reference
In-Depth Information
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Reaction type 1
Film growth
Diffusion
Reaction type 3
Reaction type 2
FIGURE 8.54
Chemical reactions in plasma-enhanced vapor deposition processes.
than the single particle. The doublet will be joined by other particle to form small
nucleus. Via island-growing processes and coalescence of the growing nuclei, the
film grows continuously [373]. In recent times, chemical reactions in solid surface
layers as a response to external variable plasma parameters (reaction type 3) have
been investigated [374-376].
Concerning the applications of deposited layers, there are remarkable differences
between solely thermal and plasma-ruled processes. Coatings deposited with plasma-
enhanced deposition processes are not limited to equilibrium compositions; they are
more often the environmentally cleaner processes, and the deposition temperature is
lower than in thermal stimulated film growth.
Considerable interest has been focused on deposition of inorganic layers for
applications in integrated circuitry production, optics, solar energy conversation, and
cutting tools. The importance of plasma technology in this field is given by the depo-
sition of layers with superior short range order. Microcrystalline and nanocrystalline
layers are a unique product of plasma processes. Two groups of applications will be
discussed in more detail.
8.2.4.2.3 TCO Films
Over the past years, there has been a growing interest in both fundamental research
and device applications based on transparent conductive oxides (TCOs). This unique
class of fascinating materials [377] is gaining a variety of applications in the fields
of solar cells, gas sensors, organic light-emitting diodes, liquid crystal, and high-
definition displays, as well as for electrochromic and smart windows. A well-known
TCO layer is indium tin oxide (ITO).
