On-Chip Spiral Inductors with Integrated Magnetic Materials
With an explosively growing market for system-on-a-chips (SOCs)-based integrated circuits, containing digital, analog, and radio frequency integrated circuits (RFICs), tremendous efforts are invested to meet the ever-challenging demands of design such as low cost, low supply voltage, low power consumption, low noise, high operational frequency, and low distortion , , , , . These design requirements cannot be met satisfactorily in many cases without the use of on-chip inductors since their alternatives use active components, which are noisy and/or power hungry. On-chip inductors are found in many RF transceivers and are the essential components in low-noise amplifiers, power amplifiers, filters, LC tank voltage-controlled oscillators (VCOs), and other applications such as bandwidth extension circuits, clock drivers, and power distribution modules.
However, on-chip inductors have several drawbacks as compared to their alternatives. The semiconductor industry continuously benefits as IC technologies migrate into deep submicron regime by scaling device dimensions, on-chip passives such as inductors have been left behind. The planar spiral geometry is less efficient than a solenoid structure, and a typical spiral inductor occupies large amount of chip area ...