Design of novel high-Q multipath parallel-stacked inductor

Abstract

In this brief, we present a novel multipath parallel-stacked inductor structure that significantly reduces the current crowding effects. Both the metal layers of the parallel stack are divided into multiple segments and crossovers are provided midway of each turn to steer the current in such a way that all its segments have equal path lengths. Following the multipath architecture, prototype inductor structures are fabricated in a 0.18-μm high-resistivity silicon-on-insulator technology using a dual thick metal stack process. Measurements show >30% improvement in quality factor (Q) with the proposed architecture when compared with a standard parallel-stacked inductor. The Q improvement achieved by the proposed inductor structure is shown to increase with the spiral thickness making them suitable for both radio frequency circuits and DC-DC buck converters without having to use magnetic materials. Via resistance is shown to limit the Q improvement possible with proposed inductor configuration.