Temperature dependence of Q and inductance in spiral inductors fabricated in a silicon-germanium/BiCMOS technology

The behavior of on-chip, planar, spiral inductors fabricated over a conductive silicon substrate has been characterized over the temperature range from -55/spl deg/C to +125/spl deg/C. Quality factor (Q) was observed to decrease with increasing temperature at low frequency and increase with increasing temperature at high frequency. Inductance was seen to vary little over the temperature and frequency range. A SPICE model that incorporated the temperature dependence of the inductor's parasitics was presented and shown to give excellent agreement with measured data over the full temperature and frequency range.