Initiated Chemical Vapor Deposition
Deposition of organic polymers with high chemical structure retention can be performed by iCVD. A cylindrical vacuum reactor with a diameter of 36 cm and a height of 5.5 cm is custom-built for this purpose.
The reactor has a removable 2.5 cm thick quartz lid, which allows laser interferometry (He-Ne Laser, λ=633 nm) for in-situ thickness control. The chamber is equipped for mild vacuum. A radical initiator is used for the process, typically tert-butylperoxide.
The radicals of the initiator are thermally produced by a filament array, which consists of 12 parallel nickel chromium wires, placed 2.5 cm above the substrate. Typical filament temperatures are in the range 250- 300 °C.
The substrate temperature is controlled with a chiller/heater and it can vary in the range 5-80 °C. All temperatures are monitored by type K thermocouples. Several needle valves were used to control the flow rates.