HOT-CARRIER-INDUCED ALTERATIONS OF MOSFET CAPACITANCES - A QUANTITATIVE MONITOR FOR ELECTRICAL DEGRADATION

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