Charge trapping and device behavior in ferroelectric memories
- Sandia National Laboratories, Albuquerque, New Mexico 87185 (United States)
The electric field emanating from the surface of a poled ferroelectric (FE) can control the conduction properties of an overlying semiconducting (SC) film; this combination of materials can thus serve as a nondestructive readout (NDRO), nonvolatile memory device. We have characterized prototypes of these devices which utilize semiconducting In{sub 2}O{sub 3} deposited on thin film lead zirconate titanate and bulk BaTiO{sub 3} FEs. The remanent state SC resistance in thin film FE NDRO devices is often opposite to that predicted from the known direction of FE polarization. In these cases charge injected from the SC film into the FE and trapped near the interface appears to control the electric field at the SC/FE interface. By contrast, the response of SC films on bulk FEs is largely controlled by just the FE remanent polarization. The measured SC resistance values in the {open_quote}{open_quote}up{close_quote}{close_quote} and {open_quote}{open_quote}down{close_quote}{close_quote} polarization states can be fairly accurately predicted by calculating the accumulation and depletion charge densities from the measured carrier concentrations, mobilities, and FE hysteresis behavior. We also observe a correlation between charge trapping in bulk and thin film of NDRO memory devices and the presence or absence of temperature-bias{endash}stress-induced voltage shifts (imprint) of the FE hysteresis curves. We suggest that the presence of near-interfacial traps in the FE controls both imprint and NDRO memory response. {copyright} {ital 1996 American Institute of Physics.}
- Research Organization:
- Sandia National Laboratories (SNL), Albuquerque, NM, and Livermore, CA (United States)
- DOE Contract Number:
- AC04-94AL85000
- OSTI ID:
- 283788
- Journal Information:
- Applied Physics Letters, Vol. 68, Issue 19; Other Information: PBD: May 1996
- Country of Publication:
- United States
- Language:
- English
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