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 (ΔNit) and oxide traps (ΔNot). 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 (Vfb) and the second at Vfb - 100mv. The relations of voltage shifts components (Vfb, Vmg, and Vit) are developed by considering a linear CV characteristic variation between Vfb voltage and mid-gap voltage (Vmg). The experimental results have shown that the proposed approach allows reducing the recovery amount compared to full C-V characteristics. The trapped charge (ΔNeq_Vfb) calculated from ΔVfb, ΔNot and ΔNit 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.