Bending-comb capacitor with a small parasitic inductance

Abstract

A new metal-metal capacitor with a small parasitic inductance, named a bending-comb capacitor (BCC), is proposed based on a standard digital CMOS technology. The BCC is applicable to high frequency circuits due to its high self-resonance frequency. An analytical evaluation of the capacitance from the geometry size is also presented. The self-resonance frequency of the BCC of 0.85 pF with the size of 10 /spl mu/m /spl times/ 100 /spl mu/m is estimated as 374 GHz with a 0.13-/spl mu/m Cu-wiring CMOS process. This frequency is about six times higher than that estimated by the conventional comb capacitor.