Lifetime estimation due to imprint failure in ferroelectric SrBi2Ta2O9 thin films

Abstract

Two different failure modes for a ferroelectric memory cell caused by imprint, the read failure due to the loss of polarization, and the write failure due to the shift of the hysteresis loop are investigated. The quasistatic hysteresis loop allows us to distinguish which failure mode is dominating in a ferroelectric random access memory application and, hence, it can also be used as a powerful tool for lifetime estimation of ferroelectric thin films limited by imprint failure under operating conditions. The experimental results show that the write failure is only decisive for very low voltage operation (Vp<1.25 V), whereas for the Pt/SrBi2Ta2O9/Pt under investigation the read failure is the dominant failure mode for operating voltages exceeding 1.25 V.

Scaling potential of pin-type 3-D SBT ferroelectric capacitors integrated in 0.18μm CMOS technology

“…These results are significantly better than reported results for 2-D capacitors with SBT deposited by spin-on techniques, and for which the hysteresis shift is typically larger and the switchable P r typically decreases [6][7][8][9][10][11]. We believe the excellent imprint properties of our FeCAP are related to the crystalline quality of MOCVD-prepared SBT.…”

Polarization retention in SrBi2Ta2O9 thin films investigated at nanoscale

“…18 However, their retention properties, which are closely related to the performance of memory devices, have been studied less. [19][20][21][22][23][24] In this article, we focus on investigation of polarization decay dynamics by means of SFM and on the effect of the switching pulse parameters, switching prehistory, and domain polarity on polarization retention. It will be shown how a particular bottom electrode material affects film retentivity.…”

Radiation effects on switching kinetics of three-dimensional ferroelectric capacitor arrays

“…If irradiated capacitors are always being written in the same state ͑i.e., 3 V applied bias͒, huge and irreversible imprintlike effect may cause memory cell "read" or "write" failures. 17 Additionally, if capacitors are cycled in normal conditions ͑i.e., bipolar pulses͒, the strong acceleration of fatigue mechanism may cause read failures since P R + and P R − states may be indistinguishable during memory reading.…”