Temperature Effects on the Performance of On-Chip Spiral Inductors Used in RF(MM)ICs

Based on the measured S-parameters and proposed circuit model for on-chip spiral inductors, the overall effects of temperature rise on the inductor performance are examined in this paper. For circular spiral inductors on silicon substrates, it is shown that when the temperature increases from 25°C to 85°C, the peak values of Q-factor (Qmax) of these inductors, corresponding to the turn number N = 3 to 7, decrease about 8.8% to 19%, respectively. The metal trace and silicon substrate resistances both increase linearly with temperature, while the capacitance of silicon substrate has a negative temperature coefficient. For a square spiral inductor on GaAs substrate, its Qmax decreases about 37.2% as temperature increases from 25°C to 185°C. The corresponding frequency fmax tends to shift from 9.44GHz to 7.73GHz, and it is reduced about 18.1%.