Effect of reactive gas composition on properties of Si/LiNbO3 heterojunctions grown by radio-frequency magnetron sputtering

Amorphous lithium niobate (LiNbO3) films were deposited onto silicon substrates by the radiofrequency magnetron sputtering method in a pure Ar environment and an Ar þ O2 gas mixture with various oxygen contents. The oxide charge existing in as-grown films has two components: the positive Qox distributed in the bulk of a film and the negative Qox located at the film/substrate interface with a maximum magnitude corresponding to an Ar (80) O2 (20) gas mixture.