Hot-carrier-induced alterations of MOSFET capacitances: a quantitative monitor for electrical degradation

In this paper, combined gate-to-channel (C/sub GSD/) and gate-to-bulk (C/sub GB/) capacitance measurements are used in order to extract quantitative information about hot-carrier degradation in MOS transistors. An analytical model, explaining the results of accelerated degradation experiments, is presented to establish a simple relationship between C/sub GSD/ and C/sub GB/ changes and the stress-induced charges Q/sub ox/ and Q/sub it/ trapped in the oxide or in interface states, respectively. A method, validated by means of two-dimensional (2-D) numerical simulations, is proposed to determine Q/sub ox/ and Q/sub it/ directly from the measured capacitances, and is applied to experimental data. The new technique considerably improves the capabilities of previous capacitive methods because it can yield a quantitative determination of Q/sub ox/ and Q/sub it/.