Relationship between capacitance and conductance in MOS capacitors

Abstract

In this work, we describe how the frequency dependence of conductance (G) and capacitance (C) of a generic MOS capacitor results in peaks of the functions $\mathrm {G}/\omega$ and $-\omega \mathrm {dC}/\mathrm {d}\omega$. By means of TCAD simulations, we show that $\mathrm {G}/\omega$ and $-\omega \mathrm {dC}/\mathrm {d}\omega$ peak at the same value and at the same frequency for every bias point from accumulation to inversion. We illustrate how the properties of the peaks change with the semiconductor doping ($\mathrm {N}_{\mathrm {D}}$), oxide capacitance (Cox), minority carrier lifetime $(\tau_{\mathrm{g}})$, interface defect parameters ($\mathrm {\lt p\gt N}_{\mathrm {IT}}$, $\sigma$) and majority carrier dielectric relaxation time $(\tau_{\mathrm {r}})$. Finally, we demonstrate how these insights on $\mathrm {G}/\omega$ and $-\omega \mathrm {dC}/\mathrm {d}\omega$ can be used to extract Cox, $\mathrm {\lt p\gt N}_{\mathrm {D}}$ and $\tau_{\mathrm {g}}$ from InGaAs MOSCAP measurements