C-T ANALYSIS OF MOS CAPACITORS UNDER CONSTANT-CURRENT STRESS

The effect of high oxide field stress is studied using capacitance-tim e (C-t) measurements of MOS capacitors, The stress results in parallel shifts of the C-t curve along the time axis, The flatband voltage shi ft Delta V-FB Obtained from the initial deep depletion capacitance C(t =0(+)) follows the same trend as that from the high-frequency C-V char acteristics. However, the discrepancy between the two flatband voltage s becomes larger as the stress increases due to the effect of interfac e charges on C-t characteristics. The flatband voltage difference is c onverted to interface trap density, showing a steady increase of inter face trap density with stress, similar to that from low-frequency C-V measurements.