Method and apparatus for reduced fatigue in ferroelectric memory elements

摘要

A method and apparatus for programming ferroelectric memory cells which reduces fatigue effects of switching polarization of the ferroelectric devices associated with the memory cells such as ferroelectric capacitors and transistors. Alteration of the rise AC fall times associated with signals used to switch ferroelectric device polarization are shown to reduce fatigue of the ferroelectric material thereby increasing the useful life of ferroelectric memory cells. Slowing the rise and fall times as well as the rate of signal level rise and fall, (signal shape), are shown to reduce the fatigue effects of switching polarization of ferroelectric devices. Methods and apparatus for producing a triangular ("sawtooth") signal waveform, a Gaussian signal waveform, and a waveform having exponential rise and fall times are disclosed.