Electrical stress effects on ultrathin (2.3 nm) oxides

Oxide reliability is a major concern for deep-submicron technologies as the dielectric thickness decreases. We study the dependence of the interface states and stress induced leakage current increase as a function of electrical stresses at different temperatures. The experiments were performed on ultrathin gate oxide (2.3 nm) metal oxide semi-conductor devices. Charge pumping and gate current as a function of the gate voltage were used to analyze both processes. Stress induced leakage current is still observable when the sensing gate voltage ranges from −1.2 to 0.6 V. We also observe an increase of interface states after different stresses. We show that, for a given stress, the stress induced leakage current increases with the temperature. From the experimental data we show that the general relation of both interface states and stress induced leakage current increases follow a power law with the stress voltage and temperature.