An investigation of on-chip spiral inductors on a 0.6 /spl mu/m BiCMOS technology for RF applications

Abstract

Inductors are very important passive elements in many RF circuit applications. Integrated on-chip metal inductors, formed in conventional CMOS or BiCMOS technologies, suffer from performance limitations due to substrate injection through the oxide, metal resistive losses, and substrate losses due to low-resistivity substrates. These problems mean that the highest attainable inductor quality factor (Q) is significantly lower than that which can be attained from off-chip inductors. This paper details an analysis of on-chip metal inductors fabricated on a 0.6 /spl mu/m BiCMOS technology. Issues relating to test structure layout, measurement techniques, inductor composition, and inductor characterization and modeling are addressed. In addition, an analysis of the impact of inductor shape and metal thickness on inductor performance is examined.