Inductor over MOSFET: Operation and theoretical study of a CMOS RF three-dimensional structure

In this paper we examine the operation of a structure that consists of an integrated inductor placed over a MOSFET within the same silicon die. This setup forms a single-chip, three-dimensional analog RF topology and was firstly introduced in [1] and [2]. The structure takes advantage of an idle metal layer above active circuits and uses it for the implementation of an inductor. As a consequence, the total area of the system's analog part shrinks, the integrated inductor usage becomes more cost effective but the interference between inductor and transistor increases.