Dynamic stress method for accurate NVM oxide robustness evaluation for automotive applications

The aim of this study is to propose a dynamic stress method allowing to correctly evaluate NVM oxide robustness at high temperature for automotive applications. Using a single cell model and electrical measurements for calibration, we emulate an AC signal close to real signal seen in memory by the oxide during write and erase phases. We present the method description applied to EEPROM memory allowing to accurately evaluate product reliability during cell programming. Dynamic regime has been investigated in terms of statistical breakdown law and device topology influence, and has been compared to a standard DC stress. We discuss experimental data obtained for different oxide thicknesses from 6.8 to 8.1 nm for a temperature range between 100 and 175 °C. Corresponding activation energies have been extracted around 0.6 eV and have been explained.