A Systematic Study of Temperature, Polarity, Thickness, and Ramp Rate Dependencies of Ramp-Voltage Stress for SiO2 and its Comparison with 2D Gate Dielectrics

A systematic study of ramped (RVS) compared to constant (CVS) voltage stress over a wide range of temperature (-50 °C to 280 °C), ramp rate (10 V/s to 0.0002 V/s), thickness - t, (2.0 nm to 12 nm), and polarity dependence for SiO breakdown (BD) is conducted. We report three important new findings: 1) a new relation explaining the large difference between activation energies Δ H (∼ 0.7eV) and Δ H(∼ 0.01eV) using a power-law model; 2) a thickness-dependence of Weibull slopes (β) of voltage-to-breakdown (V); and 3) a universal thickness-dependence of V spanning a wide range of thickness regardless of stress polarities and modes. We demonstrate that all BD parameters, n, β, and Δ H collected using slow CVS tests can be equally obtained using fast RVS tests. An equivalent reliability projection methodology using V data instead of time-to-breakdown (T) to calculate V is presented. Finally, we compare SiO V data to those of two-dimensional (2D) gate dielectrics showing the use of dielectric-strength (B=V/t) can have misleading conclusions.