Transmission line Inductor Modeling and Design for Millimeter Wave Circuits in Digital CMOS Process

A pH-range inductor is necessary in millimeter wave integrated circuit design. Such small inductors can be designed as a small transmission line with a special structure. The quality factor of this inductor is the most important design issue, especially in CMOS process. This work proposes a simple and accurate model, developed for design and optimization of such inductors. This model comprises the resistive loss, dielectric loss and eddy current loss to predict the quality factor of the inductor. A shield layer composed of thin lines in poly-silicon and active layer has been introduced and its effect in quality factor has been investigated. We have developed a simple design and optimization package in MATLAB to design this type of inductors for STMicroelectronics 90 nm digital CMOS process. To evaluate the proposed model we have used the 3D-MoM simulation in ADS.