Integrated On-Chip Inductors with Magnetic Films

Abstract

On-chip inductors with 2 levels of magnetic material were integrated into an advanced 130 nm CMOS process to obtain over an order of magnitude (>14times) increase in inductance and Q-factor, significantly greater than prior values of 2.3times for high frequency inductors. The magnetic material is shown to operate at frequencies beyond 6.4 GHz for 1 nH inductors. An amorphous CoZrTa alloy exhibiting high permeability, good high-temperature stability (>250degC), high saturation magnetization, low magnetostriction, high resistivity, minimal hysteretic loss, and compatible with silicon technology was used in combination with magnetic vias and elongated structures that take advantage of the uniaxial magnetic anisotropy