Decoupling Capacitance

The on-going miniaturization of integrated circuit feature sizes has placed significant requirements on the on-chip power and ground distribution networks. Circuit integration densities rise with each VDSM technology generation due to smaller devices and larger dies. The onchip current densities and the total current also increase. Simultaneously, the higher switching speed of smaller transistors produces faster current transients in the power distribution network. Supplying high average currents and continuously increasing transient currents through the high impedance on-chip interconnects results in significant fluctuations of the power supply voltage in scaled CMOS technologies.

Decoupling capacitors are often utilized to manage this power supply noise. Decoupling capacitors can have a significant effect on the principal characteristics of an integrated circuit, i.e., speed, cost, and power. Due to the importance of decoupling capacitors in current and future ICs, significant research has been developed over the past several decades, covering different areas such as hierarchical placement of decoupling capacitors, sizing and placing of on-chip decoupling capacitors, resonant phenomenon in power distribution systems with decoupling capacitors, and static on-chip power dissipation due to leakage current through the gate oxide.