Selective area deposition of titanium dioxide thin films by light induced chemical vapour deposition

Abstract
Titanium dioxide thin films are deposited from titanium tetraisopropoxide in an oxygen atmosphere using a 308 nm long pulse XeCl excimer laser. A mask containing several slits and lines of different widths (30-130 µm), is imaged onto the substrate by a single lens, with a reducing imaging factor of 0.4. The localization of the deposition in the irradiated area and the resolution of the obtained patterns are studied by optical microscopy and stylus profilometry. Effects of substrate temperature (60-200°C), fluence (100-200 mJ/cm²) and number of pulses (2000-6000) are investigated. Pattern deposit resolution is limited by the optical set up as shown by correspondance between optical simulation and deposit profile, and is drastically reduced by defocalisation. Increasing the deposit thickness also reduces the pattern resolution.