Design considerations for extremely high-Q integrated inductors and their application in CMOS RF power amplifier

Abstract

An extremely high Q monolithic inductor (Q>2000) on silicon substrate was reported recently [I]. The reported Q is 3 order of magnitude higher than previously reported monolithic inductor [2]. Such high quality "factor may greatly improve the performance of monolithic RF circuits. In this paper, both I -Port (one terminal at ground) and 2-Port (no terminal at ground) scattering parameters of the high-Q inductor were compared to examine m y possible differences in device characteristics. A broadband physical model of the active inductor on silicon are presem'ed to illustrate the improvement of quality factor. A design space with a range of gain and phase difference of current in the coils of the active inductor is reported. A typical application of the active inductor in CMOS RF power amplifier design is shown to illustrate the feasibility of applying the active inductor in RF circuits design.

Modeling, optimization and performance of high-Q MEMS solenoid inductors

“…In order to anticipate the design problems and propose the performance, it is essential to predict the behavior of the inductor as a function of their geometry and manufacturing parameters. Numerous research works has been published on modeling inductors (Lovelace et al 1994;Post 2000;Rotella and Zachan 2002;Zencir et al 2002;Tong and Tsui 2005) and on techniques to improve the quality factor (Q-factor) (Yeung et al;Lin et al 2005a, b;Itoi et al 2004). However, most of the modeling and the theoretical analysis in print aimed at spiral-type MEMS inductors.…”

Compact equivalent circuit model of two-layer spiral inductors

“…Thus, much of the effort has been devoted to the investigation of the electrical characteristic of various spiral inductors. To the authors' best knowledge, significant efforts that aim to provide high-Q inductive structures for critical RF applications have been reported in the literature [1][2][3]. These results might lead to the replacement of some of today's off-chip components while removing the burden of input/output impedance matching.…”

Investigation of on-chip inductors for fully-integrated DC-DC converters

“…However, the current of the spiral inductor could induce eddy currents in the underneath substrate with low resistivity, which is in a modern semiconductor process, the resistivity could be as low as 0.01-Ωcm. This will lead to the significant loss of the spiral inductor due to capacitive and inductive coupling, as well as eddy current loss and potential skin effect that may affect the self-resonant frequency of the inductor designed [11].…”