Room temperature deposition of GeO2 thin film using dielectric barrier discharge driven excimer lamps

We discuss the fabrication of GeO2 and GeO2/SiO2 films at room temperature by photo-chemical vapor deposition. Excimer lamps were used for the light s ource, and tetraethoxyorthogermanate (TEOG) and tetraethoxyorthosilicate (T EOS), as raw materials. First, we fabricated GeO2 films from single-precurs or TEOG. The surface of the films obtained with Ar-2*, Kr-2*, and Xe-2* lam ps was extremely smooth (R(rms)similar to0.3 nm). Second, we fabricated GeO 2/SiO2 composite films from a mixed vapor of TEOS and TEOG. In this instanc e, we used a Xe-2* lamp, which was able to produce films of good quality fo r both SiO2 and GeO2 individually. The refractive indices of the obtained f ilms showed intermediate values between those of SiO2 (n =1.46) and GeO2 (n =1.60). The relationship between the Ge concentration in these films and t he refractive indices was examined. We successfully obtained a GeO2/SiO2 co mposite material of higher refractive index than that of similar composites produced by conventional methods.