Raman spectroscopy of submicron KNO3 films. II. Fatigue and space-charge effects

Abstract

Spectroscopy of surface spacecharge layersRaman spectroscopy of KN0 3 thin-film ferroelectric memories has been performed as a function of film thickness, temperature, annealing procedures, and read-write cycles (fatigue). The results show that conversion to phase II is not the cause of failure in these memory devices, in agreement with the x-ray results of Schaffer and Mikkola. Waiting time effects are in accord with the space-charge theory of Takahashi. 1547

Nanoscale investigation of fatigue effects in Pb(Zr,Ti)O3 films

“…This result, which can be explained by strong domain pinning in these crystallites, is direct experimental proof that repeated switching results in formation of unswitchable polarization, which, in turn, leads to the degradation of switching characteristics. Pinning and depinning of ferroelectric domains were discussed in previous publications related to fatigue in KNO 3 films, 12 where it was suggested that both defect pinning and space charge effects could play a role in fatigue of ferroelectric capacitors. Since only a slight decay of switchable polarization is usually observed after 10 3 -10 4 switching pulses in Pt/PZT/Pt capacitors, 1 it is not surprising that domain pinning was observed in just a few crystallites.…”

Pinning and depinning mechanism of defect dipoles in PMnN–PZT ceramics

“…Some researchers suggest that the constriction is probably related to defect dipoles, which occur near the domain boundary formed by the combination of oxygen vacancies with doped ions at the B-sites. Defect dipoles, sometimes called complex defects, which are formed by acceptor atoms and oxygen vacancies, act as pinning points for the domain motion and result in a constricted loop [11][12][13][14]. A bipolar electric field or dc poling can induce the ferroelectric domain depinning process [15].…”

Thickness profiles through fatigued bulk ceramic lead zirconate titanate

“…[8][9][10][11][12][13][14][15][16][17][18][19][20] Due to the large market shares anticipated in fuel injection systems and continuous development of ferroelectric memories, a good understanding of the underlying effects remains an important issue to be solved as underlined by the large number of publications already devoted to this subject. Overall, fatigue yields a loss of switchable polarization and certain offsets irrespective of device geometry.…”

“…Overall, fatigue yields a loss of switchable polarization and certain offsets irrespective of device geometry. 4,16 It depends on the loading conditions and the particular ferroelectric and electrode materials whether offsets 2,4,7,21 or the loss of switchable polarization [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19] is more pronounced. The former is most common for unipolar loading in actuators, the latter in bipolar fatigued films.…”