Components of channel capacitance in metal-insulator-semiconductor capacitors.

In metal-insulator-semiconductor (MIS) capacitors, there are several components that influence the channel capacitance. Charges accumulate or deplete from the Γ, X, and L valleys for electrons and light, heavy and split-off bands for holes. Additionally dopants can change occupancy as a result of band-bending. A simple numerical method for calculating these components is presented along with potential implications for MIS capacitor characterization. Calculations for In0.53Ga0.47As indicate capacitance due to changes in dopant impurity ionization becomes significant around ND=1×1017 cm-3. The results also suggest that more detailed transient models are needed to verify the assumptions used in interface state characterization. [ABSTRACT FROM AUTHOR]