MECHANISMS OF NANO-SHORTS IN THE ELECTRICAL BREAKDOWN OF FERROELECTRIC THIN FILMS

ABSTRACT

Micro-Raman, SEM and electron nano-probe techniques are used to show that bismuth titanate thin films undergoes a local phase transformation from layered-perovskite structure to pyrochlore-like structure during filamentary electrical breakdown, with the loss of Bi and oxygen. In PZT, dendrite-like structures (precursors of electrical shorts) of a few microns diameter, produced by bipolar voltage cycling (i.e. fatigue), exhibit almost pure regions of α -PbO, β -PbO and rutile-TiO₂. Note that β -PbO is not the stable ambient phase.

Keywords:

• PZT
• breakdown
• fatigue
• PbO and rutile