| Thin films are produced from layers of materials ranging from nanometres to micrometres in height. They are increasingly common and are being used in integrated circuit design, optical coatings, protective coatings, and environmental sensing. Thin films can be fabricated using a variety of methods involving chemical reactions or physical transport of matter. Glancing angle deposition (GLAD) thin films are produced using physical vapour deposition techniques under high vacuum conditions where exploitation of the geometric conditions between the source and the substrate causes enhanced atomic self shadowing to produce structured thin films. This work deals with the modification of these films, in situ by altering growing conditions through substrate temperatures control, or post-deposition through reactive ion etching (RIE). The first part of the thesis deals with the modification of TiO2 GLAD humidity sensors using RIE with CF4. The data presented demonstrates improved response times to step changes in humidity. Characterization revealed response times of better then 50 ms (instrument-limited measurement). An etch recipe for complete removal of TiO2 was also demonstrated with shadow masking to transfer patterns into GLAD films.;Opposite to the goal of the preceding chapter, the focus of the final experimental chapter was to limit adatom mobility. A LN2-based cooling system was designed and implemented for the purpose of studying the growth by GLAD of lower melting point materials, which under regular growth conditions do not form well-defined structures. Chuck temperatures of -60°C can be achieved during deposition while still allowing substrate rotation. The growth of helical copper films was used to demonstrate the effects of in situ substrate cooling.;The subsequent chapter focuses on modification of thin film growth conditions by increasing adatom mobility. A radiative heating system was designed and implemented with the ability to achieve chuck temperatures of 400°C. Capping layers on top of GLAD films were grown to demonstrate effects of in situ heating, and a quantitative analysis of crack reduction with increased temperatures is presented. Lithographic pattern transfer onto a capped GLAD film was demonstrated. |
