Nanotechnology-Enabled Sensors

172 Chapter 4: Nano Fabrication and Patterning Techniques
4.5.4 Atmospheric Pressure Plasma CVD (AP-PCVD)
The AP-PCVD is conducted at atmospheric pressures. In AP-PCVD,
atmospheric pressures and very high frequency (VHF) plasma are employed
to obtain ultra-high deposition rates (Fig. 4.30). On the contrary, a
conventional fixed electrode for generating the plasma at atmospheric
pressure will result in poor quality thin films that are non homogenous and
non conformal to the substrate. With a high-speed rotary electrode, both
the homogeneity and conformation of thin films can be dramatically improved.
With such a rotating electrode, and the help of the high speed gas
flow, the byproducts in the plasma, which degrade the thin film quality,
can be removed.
AP-CVD is becoming attractive for deposition of metallic, insulating
and even polymeric coatings in industrial processes. Nanostructured thin
films with highly ordered grains can also be obtained using this method.
Fig. 4.30 The AP-PCVD set-up and the deposition process.