TiO2 thin film patterns prepared by chemical vapor deposition and atomic layer deposition using an atmospheric pressure microplasma printer

Abstract

A microplasma printer is employed to deposit thin film patterns of TiO2 by titanium tetra-isopropoxide and N2/O2 plasma at atmospheric pressure. The setup is adopted to carry out deposition in two configurations, namely under chemical vapor deposition (CVD) and atomic layer deposition (ALD) modes. The properties of TiO2, as well as the patterning resolution, are investigated. The amorphous TiO2 deposited in the CVD mode contains a relatively high level of impurities (residual carbon content of 5–10 at.%) and is characterized by a low refractive index of 1.8. With the ALD mode on the other hand, TiO2 is obtained with a low level of impurities (<1 at.% C and <2 at.% N), a refractive index of 1.98, and a growth per cycle of 0.15 nm. Furthermore, the spatial resolution for a 8-nm-thick film is determined by X-ray photoelectron spectroscopy line scan and found to be equal to 2,000 and 900 µm for the CVD and ALD modes, respectively. This study can be regarded as the first step toward area-selective CVD and ALD of TiO2 by a microplasma printer, which can be further explored and extended to other material systems.