LASER TREATMENT AT ROOM TEMPERATURE FOR IMPROVEMENT OF DIELECTRIC PROPERTIES IN PLASMA-ENHANCED ATOMIC LAYER DEPOSITED TiO_2 THIN FILMS

摘要

TiO_2 dielectric films with 38 nm thickness were grown on Si (100) substrates at 200 deg C using plasma-enhanced atomic layer deposition (PEALD) technique. Laser-irradiated TiO_2 films kept an amorphous phase similar to as-grown films and showed an increase in permittivity with increasing laser powers and the number of laser shots at constant laser power. Laser-irradiation of TiO_2 films at room temperature produces an oxygen vacancy at the film surface. The high frequency dependence of capacitance at low frequency in laser-irradiated films was due to an increase of space charges such as oxygen vacancy, resulting in an increase of permittivity in laser-irradiated TiO_2 films because of an additional space charge polarization.