Characterization of TEOS-based SiO2 for integrated photonics

Abstract:
The use of silicon dioxide as top cladding material is common for integrated photonics applications. Ideally, the material characteristics such as the refractive index and density are equal to those of the thermal oxide used as bottom cladding and the top cladding should have an excellent step coverage. The process parameters for the deposition of an N2O/TEOS-based PECVD top cladding are investigated. Ellipsometry was used to determine the refractive index and deposition rate, the vibrations and lack of vibrations of Si-bonds were observed in the FTIR spectrum, and the density was qualitatively analysed from the absorption peaks. SEM imaging showed a good step coverage for the N2O/TEOS-based processes.