Coplanar waveguides on silicon substrate with thick oxidized porous silicon (OPS) layer

The problem of high dielectric loss of waveguide on silicon in the microwave region can be solved by utilizing a thick silicon dioxide layer that is formed by silicon substrate anodization and oxidation processes. Coplanar waveguides (CPW's) are fabricated on silicon substrate with a 20-μm-thick oxidized porous silicon (OPS) layer and demonstrate very high performance of 0.1-dB/mm attenuation at 4 GHz. Thus, the OPS process is promising for gigaherz applications of silicon substrates.