PLASMA-ASSISTED VAPOUR THERMAL DEPOSITION WITH CONTINUOUS MATERIAL FEED

The Plasma-Assisted Vapour Thermal Deposition ( PAVTD) is thin-film deposition technique utilizing a classical polymer as a source of material. The polymer is heated to fragmentation/evaporation under low pressure. The released fragments (effective a "monomer") with molar mass of 10(2) to 10(3) g/mol are then repolymerized in the rf plasma. The high molar mass of the film building blocks offers an opportunity to tune the structure and properties of the films in an exceptionally broad range for a plasma polymer, effectively bridging the gap between classical polymers and PECVD films. Currently, the PAVTD method has several drawbacks compared with PECVD. The deposition must be done as a batch process, governed by the capacity of the crucible. The thermal release of the precursor fragments is highly temperature-and history-sensitive. The resulting fluctuations in deposition rate make retaining good reproducibility of the process rather tricky. To overcome these technical limitations, a modification of the setup utilizing a filament for FDM 3D-printing fed into a modified filament heater/extruder was made. In this paper, overview of the possibilities of PAVTD using PLA as the source material will is given along with the first results obtained using an improved deposition setup with continuous material feed. Significant improvements in deposition rate and control of stability of the deposition are presented.