Positive charge instability during bidirectional stress on metal-oxide-silicon capacitors

Bidirectional electron injections are made on metal-oxide-silicon capacitor s under constant currents or constant voltages. It is shown that both stres ses reveal the same generation mechanism of oxide defects and consequently confirm that the gate/oxide interface is more stress resistant than the oxi de/silicon interface. It is also shown that the created positive charge is unstable during bidirectional stress. We characterize this instability by s tudying dielectric defect neutralization following a new procedure. Oxide f ield intensity and polarity are considered as the principal precursors of t his instability. Without any applied field, the neutralization follows a lo garithmic law; while under a nonstressing field it follows an exponential l aw. Both kinetic laws are linked, since the logarithmic law describes the s aturation value of the exponential one, and hence both describe the same pr ocess. Results of both current and voltage stresses give a power law betwee n the oxide field near the cathode during stress and the capture cross sect ion measured from neutralization kinetics. (C) 2000 American Institute of P hysics. [S0021-8979(00)02124-1].