Capacitors in heterogeneous IC systems-Consequences on compact modeling

Different types of capacitors are reviewed with respect to charge storing in heterogeneous integrated systems. Starting with the commonly used gate oxide capacitors in CMOS technologies, we discuss challenges for thinner oxides. A PSP model is shown to provide a good fit of the gate capacitance vs. the gate voltage for retrograde doping profiles. As an example, a gate capacitor circuitry is discussed which overcomes the drawback of the strong non-linear bias dependence. Requirements for the RF modeling of integrated back-end-of-line (BEOL) capacitors, such as metal-insulator-metal (MIM) capacitors, highlighting the need of modeling the dielectric absorption, or vertical natural capacitors (VNCAP), are addressed. Furthermore, the compact modeling properties of a RF MEMS integrated in a 0.18 μm CMOS process are shown. Finally, an outlook to a through-silicon-via (TSV) capacitor is given.