Influence of the SRO as passivation layer on the microwave attenuation losses of the CPWs fabricated on HR-Si

In this letter, silicon rich oxide (SRO) is used as the passivation layer of coplanar wave guides (CPWs) fabricated on high resistivity silicon (HR-Si). The microwave performance of the CPWs is evaluated computing the attenuation loss (/spl alpha/) of the device in the 0.045-50 GHz frequency range. It is shown that for frequencies lower than 5 GHz the losses of CPWs using SRO as a passivation layer are lower than those of CPWs using SiO/sub 2/. It is also shown that using a combination of thermal and CVD SiO/sub 2/, a reduction of the losses of CPWs is obtained.