Impact of tunnel currents and channel resistance on the characterization of channel inversion layer charge and polysilicon-gate depletion of sub-20-angstrom gate oxide MOSFET's

An experimental and theoretical demonstration of the impact of tunneling currents and channel resistance on the measured gate-to-channel capacitance using long-channel metal oxide semiconductor field effect transistors with sub-20-angstrom gate oxide is presented. A model is derived for the terminal capacitance in terms of tunneling conductance, intrinsic capacitances, measurement frequency and channel length. The model is useful in characterizing a measured extrinsic capacitance fall-off in strong inversion and its relationship with the oxide thickness and channel length of the test structure.