Silicon as a microwave substrate

Abstract

Silicon has many advantages as a microwave substrate material including low cost and a mature technology. The lower resistivity of Si (/spl ap/10 k /spl Omega/-cm) compared to GaAs (/spl ap/10 M /spl Omega/-cm) is perceived as a major disadvantage. In this paper, we present measured and simulated results demonstrating that the losses of a coplanar transmission line (CPW) realized on silicon substrates are comparable to the losses of a CPW realized on a GaAs substrate with insulators. The loss mechanisms of Si and GaAs substrates used for microwave applications are analyzed using both microwave and semiconductor physics theory. A high resistivity Si substrate can be used both as a microwave substrate and an active element carrier permitting further integration at low cost.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>