Properties of oxidized porous silicon as insulator material for RF applications

In this paper we present a method for developing thick layers of silicon oxide. This work is divided into two parts. First we present the fabrication of the dielectric layer using porous silicon technology. In the second part we show the characterization of coplanar transmission lines deposited on it. In order to form the oxide layer, an electrochemical etching in hydrofluoric acid is used to form microporous silicon. Next, several oxidations steps are used to oxidize the porous silicon (OPS) until the final thick oxide layer is obtained. In order to characterize the oxide layer simple coplanar lines were fabricated. Material parameters were extracted from scattering parameters measured with a network analyzer. Experimental results of oxidized porous silicon layer show good properties and can be used as a thick dielectric material, taking the place to other fabrication methods as flame hydrolysis deposition (FHD) and chemical vapor deposition (CVD) techniques.