Influence of thermal annealing on structural properties and oxide charge of LiNbO3 films

Abstract

C-oriented polycrystalline lithium niobate (LiNbO 3 ) films have been deposited on Si substrate by the radio-frequency magnetron sputtering method in an Ar atmosphere and Ar ? O 2 gas mixture. All as-grown LiNbO 3 films manifested positive fixed oxide charge regardless of the sputtering conditions. Donor centers are formed in Si substrate because of diffusion of O 2 molecules during sputtering process. Thermal annealing (TA) of the deposited films leads to increase in the surface roughness and grain size as well as formation of LiNb 3 O 8 phase in the studied films. Also, TA resulting in the decline of positive oxide charge due to the diffusion of oxygen molecules into LiNbO 3 films from air and out-diffusion from Si substrate.

The Effects of Li/Nb Ratio on the Preparation and Photocatalytic Performance of Li-Nb-O Compounds

“…At most time, the appearance of LiNb 3 O 8 is recognized as an impurity phase during the preparation of LiNbO 3 , especially in film samples, owing to high annealing temperature or inhomogeneous distribution of Li element in precursors [19, 20]. Due to the difficulty to prepare a pure phase, LiNb 3 O 8 has been rarely studied, while for LiNbO 3 powders, the preparation technologies are various, such as sol-gel [19], hydrothermal [21], and laser irradiation methods [22].…”