Novel Method for Characterizing the Electrical Priorities of Lead Zirconate Titanate (PZT) Ferroelectric Films and Memory Devices.

摘要

A novel technique for determining the electrical properties of lead zirconate titanate (PZT) ferroelectric-film memory devices is reported which eliminates a major systematic error discovered in other techniques. This novel technique measures the electrical response of a ferroelectric material (device) to an electrical signal that is similar in amplitude and frequency to the signals used in digital computers. The technique also provides a method for consistently converting the measured electrical response into polarization values. The ability to consistently process the data allows researches to accurately compare the results of different measurements and to investigate the relationship changes in the operating characteristics of a ferro electric memory device and changes in the electrical properties of the ferroelectric material. Ferroelectric ageing in a PZT film was investigated using this new technique. The results of this investigation indicated that ferroelectric ageing in PZT films is similar to ferroelectric ageing in many bulk ferroelectric materials. Specifically, 'effective' internal electric fields increase linearly with the lozarithm of the ageing time. Additionally, the investigation revealed how earlier measurement techniques motivated investigators to believe that ferroelectric-film ageing was different from bulk ferroelectric ageing.... Ferroelectric devices, Nonvolatile Memory, Ferroelectric ageing, Thin-film Ferroelectric materials.