Overestimate of thin dielectric lifetime in single doping type poly-gate capacitors

It is reported that effects of band-bending produce a voltage drop in the poly gate, which reduces the voltage stress across the capacitor dielectric. It was found that if this effect is not taken into account there is a three-orders-of-magnitude overestimate of the 5-V lifetime for a 68-AA oxide equivalent ONO poly/poly capacitor. A family of curves relating poly doping concentration, dielectric thickness, and the maximum allowable accelerated test voltage was given as guidelines for accelerated time-dependent dielectric breakdown testing.