Statistical analysis of integrated passive delay lines

The statistical properties of integrated passive LC delay lines are investigated. A new variation using spiral inductors and vertical parallel plate (VPP) capacitors is introduced, whose delay is primarily determined by the lateral dimensions, resulting in very accurate and repeatable delays. An MIM-based version of this line is also fabricated for comparison. Additionally, LC delay-based oscillators are implemented to compare the variations in active and passive delay elements. Experimental data is obtained from measurement of 27 and 47 sites on two wafers from two different process runs, respectively. The measurements show 0.6% delay variations for VPP-based delay line compared to 1.0% for its MIM-based counterpart.