Laser deposition of thin SiO2 and ITO films

Abstract

Multicomponent films like ITO (indium tin oxide) and silica (SiO2) can be efficiently deposited by using the reactive pulsed laser deposition (RPLD) technique. We ablated Si, SiO and ITO targets in low-pressure O2 (0.1–5Pa) with XeCl and KrF laser pulses at fluences of 5–8J/cm2. The films were deposited on Si〈100〉 substrates at temperatures of 20–600°C. The substrate was generally set parallel to the target. To reduce droplet deposition, some films were deposited in off-axis configuration or using the so-called “eclipse method”, characterized by a shadow mask between target and substrate. Dense, continuous ITO films with resistivity as low as 1.6×10−4Ωcm and a high transparency in the visible region were deposited. Ultra-thin (∼6nm) films were successfully used as electrodes in optoelectronic devices. Dense, stoichiometric, thick (>2μm) SiO2 films were deposited on substrates at room temperature. Droplet density and surface roughness are kept quite low (∼5nm).