The Dry Etching Characteristics of TiO2 Thin Films in N-2/CF4/Ar Plasma

In this study, the etching characteristics of titanium dioxide (TiO2) thin films were investigated with the addition of N-2 to CF4/Ar plasma. The crystal structure of the TiO2 was amorphous. A maximum etch rate of 111.7 nm/min and selectivity of 0.37 were obtained in an N-2/CF4/Ar (= 6:16:4 sccm) gas mixture. The RF power was maintained at 700 W, the DC-bias voltage was - 150 V, and the process pressure was 2 Pa. In addition, the etch rate was measured as functions of the etching parameters, such as the gas mixture, RF power, DC-bias voltage, and process pressure. We used X-ray photoelectron spectroscopy to investigate the chemical state on the surface of the etched TiO2 thin films. To determine the re-deposition and reorganization of residues on the surface, atomic force microscopy was used to examine the surface morphology and roughness of TiO2 thin films.