A novel method based on capacitance-voltage for negative bias temperatures instability studies: Concept and results

In this paper, a novel method in MOS capacitors is suggested for negative bias temperature instability (NBTI) measurement. This method is based on C-V technique and allows to independently extracting the interface (ΔN
_it
) and oxide traps (ΔN
_ot
). The method permits a broad investigation in the reliability study by exploiting capacitance. It is based on a simple theoretical concept and consists to measure the evolution of capacitance in two points; the first at the flat-band voltage (V
_fb
) and the second at V
_fb
- 100mv. The relations of voltage shifts components (V
_fb
, V
_mg
, and V
_it
) are developed by considering a linear CV characteristic variation between V
_fb
voltage and midgap voltage (V
_mg
). The experimental results have shown that the proposed approach allows reducing the recovery amount compared to full C-V characteristics. The trapped charge (ΔN
_{eq_Vfb}
) calculated from ΔV
_fb
, ΔN
_ot
and ΔN
_it
present a linear stress-time-dependence which is in good agreement with those found in literature. In addition, the results have shown a similar kinetics of interface state generation as well as oxide trapped charges.