Hilbert Curve Based Lateral Flux Capacitors

This paper introduces a high-density capacitive structure using a quasifractal geometry based on the Hilbert curve. The proposed structure, fully compatible with standard digital CMOS processes, can be easily generated in iterations and has a high perimeter-area ratio, therefore producing a large capacitance in a specific area which increases with scaling due to the exploitation of lateral flux. To validate this novel Hilbert-based capacitor approach, three test structures-a conventional parallel-plate capacitor, an interdigitated capacitor and the proposed Hilbert capacitor-are implemented in an 180 nm 6-metal 1-poly CMOS process and compared in terms of capacitance density.