Focused ion beam and field-emission microscopy of metallic filaments in memory devices based on thin films of an ambipolar organic compound consisting of oxadiazole, carbazole, and fluorene units

Abstract

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Percolation of gallium dominates the electrical resistance of focused ion beam deposited metals

“…The values of u c were estimated separately, using Eqs. (2) and (3) for low and high values of u, and yielded u c,2 and u c,3 , respectively. The difference Du c (¼ju c,3 À u c,2 j) was minimized through using an asymptotic u c ¼ 0.05.…”

3D imaging of filaments in organic resistive memory devices

“…The presence of CFs was shown by conducting AFM [26,28], and by spatially resolved infrared photographs [29]. Transmission electron microscopy experiments [11,18,19,23,30] suffer from evident difficulties in localizing the filament, and from possible cutting artifacts occurring during the cross-section preparation of such delicate hybrid metal/organic heterostructures [31]. However, CFs with 50-100 nm diameter were identified by Pearson et al [19], apparently growing from the bottom electrode (cathode).…”

“…Transmission electron microscopy experiments [11,18,19,23,30] suffer from evident difficulties in localizing the filament, and from possible cutting artifacts occurring during the cross-section preparation of such delicate hybrid metal/organic heterostructures [31]. However, CFs with 50-100 nm diameter were identified by Pearson et al [19], apparently growing from the bottom electrode (cathode). In inorganic resistive memories, which are now available on the market, the switching mechanism is indisputably known to reside on filament formation, and a visualization of CFs in insulating oxides has recently been achieved by c-AFM tomography [32].…”

“…A complete overview on materials and architectures can be found in recent reviews [12,13]. RS mechanism in OMDs has been attributed to very different phenomena, based on charge injection/trapping mechanisms [14][15][16][17], or the formation of conductive filaments (CFs) [18][19][20][21][22][23][24]. Filaments were argued to be based on metallic [25], or carbon rich [26] dendritic paths.…”

Robust non-volatile bipolar resistive switching in sol-gel derived BiFeO3 thin films

“…The formation and rupture of the filament in RRAM is attributed to either the oxygen vacancy generation or the diffusion of active metal ions from the top or bottom electrodes into the active layer under the effect of the extremely high electric field. [21][22][23][24][25][26][27][28] The formation of the filament is attributed to the presence of foreign atoms, especially coming from electrodes or intrinsic defects in the active material. Various perovskite materials are explored for RRAM application and recently bismuth ferrite is identified as a potential room temperature magnetodielectric material [30][31] .…”