Atmospheric pressure plasma enhanced chemical vapour deposition of functional thin films.

Atmospheric pressure plasma enhanced chemical vapour deposition, AP-PECVD, has great potential as an inexpensive method of producing functional thin films over large surface areas. This project fills a knowledge gap concerning the links between plasma chemistry during deposition and the thin films that have been produced in the process.

Project Aims: This project proposes a comprehensive investigation of the effect of key plasma discharge parameters on both the plasma chemistry, and the properties of the films produced during the plasma enhanced chemical vapour deposition process. The proposal tackles a major scientific challenge in providing a thorough understanding of the plasma chemistry and its relationship to surface properties of thin films produced.

Introduction: The potential to control the properties of thin films produced in the atmospheric pressure plasma enhanced chemical vapour deposition process is hugely significant, implying that there is the possibility of tuning the plasma parameters such that certain functionalities of the films produced are maximised. Thin films produced in such a manner are ideal for barrier coatings, hydrophobic and hydrophilic coatings, and optical coatings; where large areas of material require coating with suitable functional materials. There is a definite requirement to elucidate the mechanisms of plasma enhanced thin film growth at atmospheric pressure, and this becomes ever more pressing when trying to optimise plasma conditions for enhanced film functionalities.

This project will combine in-situ and in-line gas characterisation to provide a full understanding of the plasma chemistry during the AP-PECVD process. The information will be used in tandem thin film analysis carried out with the comprehensive and world class surface analysis facilities available to the Surface Engineering and Advanced Materials research group at Manchester Metropolitan University, to facilitate a greater understanding of the mechanisms and processes occurring during the AP-PECVD process.

Project Objectives:

(1) Design and build of an AP-PECVD reactor. This will facilitate the interrogation of plasma conditions with a variety of spectroscopic techniques, whilst ensuring deposition of high quality functional thin films. Thin film deposition chemistries to be studied are silica deposition from hexamethyldisiloxane, titania deposition from titanium isopropoxide, and tin oxide deposition from butyltin trichloride.

(2) Deposition of a range of functional thin films by AP-PECVD. Spectroscopic techniques will be utilized during deposition for the purpose of understanding the plasma chemistry occurring during the AP-PECVD process. These analysis techniques will be in situ and in-line FTIR spectroscopy and high-resolution optical emission spectroscopy in the first instance.

(3) Thin film analysis. A comprehensive characterisation of all functional thin films produced will be carried out with regards to the optical, chemical and structural properties of these films. This characterisation will involve the use of Scanning Electron Microscopy, ATR-FTIR spectroscopy and X-ray diffraction amongst others. The combined plasma chemistry and surface analysis will provide a good understanding of factors effecting the production of functional thin films by AP-PECVD, allowing for optimisation of surface functionalities.