1 research outputs found
Chemical Vapor Jet Deposition of Parylene Polymer Films in Air
Parylene
films are commonly used as transparent, flexible coatings in electronic
devices and biomedical applications, exhibiting barrier properties
against corrosion, low dielectric constant, and moisture resistance.
Reactive vapor deposition of parylene results in conformal coverage
of features at room temperature, which is advantageous for passivating,
for example, organic optoelectronic devices. Conventional parylene
deposition methods, however, coat surfaces virtually indiscriminately
and utilize separate chambers for vaporization, pyrolysis, and polymerization,
resulting in a large footprint and limited processing integration
ability, especially at a laboratory scale. Here, we demonstrate the
vaporization and pyrolysis of the di-<i>p</i>-xylylene (parylene
dimer) in a single compact nozzle, producing a jet of monomer that
polymerizes into a film upon contact with the substrate at room temperature.
A guard flow jet is employed to shield the reactive monomer molecules <i>en route</i> to the substrate, thereby enabling polymer deposition
and patterning in ambient atmosphere. We present an analytical model
predicting film growth rate as a function of process parameters (e.g.,
gas flow rate and source, pyrolysis & substrate temperatures).
The effect of jet flow dynamics on film morphology is also discussed.
A 100% increase in the lifetime of air-sensitive OLEDs is demonstrated
upon encapsulation of the devices with parylene-N film deposited by
this technique. Potential advantages of this approach include increased
material utilization efficiency, localized conformal coating capabilities,
and an apparatus that is compact, inexpensive, and does not require
vacuum