Electrical properties of Si–LiNbO3 heterostructures grown by radio-frequency magnetron sputtering in an Ar + O2 environment

• <0001> textured LiNbO3 films were grown by the magnetron sputtering method.
• Using the Ar + O2 reactive gas environment reduces the fixed oxide charge in LiNbO3.
• The coercive field is declined for the LiNbO3 films formed in an Ar + O2 environment.
• Charge transport was found to affect Schottky emission.
• All barrier parameters of the Si–LiNbO3 heterojunction were investigated.

Single-phase <0001> textured LiNbO3 films were grown by the radio-frequency magnetron sputtering method on Si substrates by using an Ar + O2 gas environment. It was demonstrated that the presence of O atoms in the reactive chamber leads to a decline in concentration of the oxygen vacancies in the bulk of LiNbO3 films as well as in the barrier properties at the LiNbO3–Si interface and as a result, it affects the current–voltage and capacity–voltage characteristics significantly. All barrier parameters, such as barrier heights and conduction band offset of the Si–LiNbO3 heterojunction were derived by using the two double-depletion layer model. Remnant polarization of the LiNbO3 films (Pr = 69 μQ/cm2) is close to one for bulk material regardless of the presence of O atoms in the reactive chamber in contrary to the coercive field that declined from Ec = 39 kV/cm (Ar environment) to Ec = 27 kV/cm (Ar + O2 gas mixture).