Fabrication and Characterization of Coplanar Waveguides on Silicon Using a Combination of SiO and SRO

In this work, the use of silicon rich oxide (SRO) and chemical vapor deposition SiO₂ double layers as passivation films of coplanar waveguides (CPW) on high resistivity silicon (HR-Si) with an N⁺ backside is studied. The microwave performance of the fabricated CPWs is evaluated by computing the attenuation loss of the devices in the 0.045-50 GHz frequency range. Experimental results show that the N⁺ layer can be used without affecting CPW performance. Also, using a combined dielectric layer (SRO₂₀ /SiO₂ ), the attenuation losses are reduced compared to single dielectric layers.