Dielectric breakdown in high-ε films for ULSI DRAMs: II. barium-strontium titanate ceramics

Scott, J. F.; Azuma, M.; Araújo, Carlos A. Paz de; McMillan, L. D.; Scott, M.; Roberts, T.

doi:10.1080/10584589408018661

Cited by 99 publications

(34 citation statements)

References 42 publications

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“…This polarization enhancement would be due to a lattice-matching strain effect of the thinner film with the substrate. [23] Many reports ascribed the reduction of P r with decreasing FE thickness to the serious by-electrode charge injection, [24,25] which already induces retention failure during the P-V measurements. Here, charge injection was sufficiently suppressed by the tunnel switch in the off state, and the genuine P r values of the films are now unveiled.…”

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confidence: 99%

The Inlaid Al₂O₃ Tunnel Switch for Ultrathin Ferroelectric Films

et al. 2009

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Ferroelectricity is an intriguing property of some materials that belong to certain non-centrosymmetric crystal groups. Ferroelectric (FE) materials show a residual surface ionic charge, called remanent polarization (P r ), even under the absence of an external electric field. The sign of Pr can be reversed by reversing the external electric field. This is a very attractive characteristic for nonvolatile semiconductor memory devices, where the bistable charge states correspond to digital 0 and 1 data. [1,2] In addition, they are also viable functional materials for neuromorphic synapse circuits, where more analogue-type data processing is necessary.[3] Recently, their high electromechanical coefficients have provided micro-and nano-electromechanical systems with a new opportunity.[4] The great functional opportunities of FE materials have led to renewed interest from industry and theoreticians in determining the limitations in the vertical and lateral sizes of FE materials. Although first-principle calculations [5] in combination with experimental observations [6] have shown that it is possible to scale down the thickness to a few unit cells while maintaining the functionality of FE materials, the real situation has not been so promising. In most semiconductordevice applications, FE materials should be integrated with the standard complementary metal oxide semiconductor field effect transistor so that they are formed during the back-end of the line process. This means that FE materials should have metal (or conducting oxide) electrodes and a polycrystalline thin-film structure, which is a very different situation from what the theoretical calculations have assumed. Due to this harsh environment, FE materials suffer from interfacial effects, including either the intrinsic finite electrostatic screening length of the metal electrodes, [7][8][9][10] and a finite intrinsic dead layer, or the processing issues of an intervening defect, phase impurities, and residual stresses. [11][12][13][14] Even when all extrinsic effects are minimized by technological improvements, intrinsic by-electrode effects generate a considerably large depolarizing field to destabilize the single-domain pattern within a single memory cell into 180 8/90 8 stripe domains, which reduces the equilibrium system energy. [6,15,16] These effects become increasingly severe as the FE layer-thickness decreases, rendering ultrathin FE film applications virtually impractical. Furthermore, the length of accessing the write/read pulses of the memory devices should be longer than the actual domain switching time for operation safety. This arouses various reliability issues, such as imprint and fatigue, due to by-electrode charge injection during field overstressing. [17,18] It has been confirmed experimentally that there are normally non-ferroelectric interfacial layers at the interfaces between (metal) electrodes and FE layer that have detrimental effects on the FE functionality of thin films. On the other hand, it is possible that this interfacial layer ca...

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confidence: 99%

The Inlaid Al₂O₃ Tunnel Switch for Ultrathin Ferroelectric Films

et al. 2009

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“…Figure 4 shows the leakage current behaviors of the samples. The conduction mechanism between the ferroelectrics and metal contact usually explained by mixture of Schottky emission [7], the bulk limited, space charge limited conduction [8] and Poole-Frenkle emission [9]. Since, Schottky emission can be expressed as log J is proportional to the square root of applied electric field [10].…”

Section: Resultsmentioning

confidence: 99%

Ferroelectric Properties of Bi_3.25La_0.75Ti₃O₁₂ Thin Films Fabricated Sol-Gel with 2-Step RTA Process

Kim

Hong²,

Hwan³

et al. 2004

Integrated Ferroelectrics

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We attempted to reduce c axis-oriented grains of BLT thin films (Bi 3.25 La 0.75 Ti 3 O 12 ) by controlling 2-step RTA annealing conditions. BLT thin films (Bi 3.25 La 0.75 Ti 3 O 12 ) were prepared using sol-gel method. 2-step RTA annealing was employed to restrain the growth of c axis-oriented grains in randomly oriented BLT films. Microstructural variations of BLT thin films were investigated by monitoring XRD and AFM. The ferroelectric properties such as hysteresis loop, switching behavior, and leakage current were examined in terms of RTA process conditions. The result revealed that as the portion of (117) oriented grain increases, the ferroelectric properties except the leakage current property improved. From the study, we can optimize RTA process to yield better ferroelectric properties of BLT thin films (Bi 3.25 La 0.75 Ti 3 O 12 ).

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“…The predicted reliability under operating conditions in these studies varies widely but recent data from MOCVD BST films predicts lifetimes of -1000 years for 24 nm films [46]. Techniques to predict reliability using data measured at low temperature have typically reported hard breakdown, although this was not explicitly shown in the publications [49][50][51]. Two voltage extrapolation techniques have been used: log time versus V and IN.…”

Section: Bst Reliability: Resistance Degradationmentioning

confidence: 99%

(Ba,Sr)TiO3 Thin Films for Dram’s

Summerfelt

1997

Thin Film Ferroelectric Materials and Devices

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Dielectric breakdown in high-ε films for ULSI DRAMs: II. barium-strontium titanate ceramics

Cited by 99 publications

References 42 publications

The Inlaid Al₂O₃ Tunnel Switch for Ultrathin Ferroelectric Films

The Inlaid Al₂O₃ Tunnel Switch for Ultrathin Ferroelectric Films

Ferroelectric Properties of Bi_3.25La_0.75Ti₃O₁₂ Thin Films Fabricated Sol-Gel with 2-Step RTA Process

(Ba,Sr)TiO3 Thin Films for Dram’s

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Dielectric breakdown in high-ε films for ULSI DRAMs: II. barium-strontium titanate ceramics

Cited by 99 publications

References 42 publications

The Inlaid Al2O3 Tunnel Switch for Ultrathin Ferroelectric Films

The Inlaid Al2O3 Tunnel Switch for Ultrathin Ferroelectric Films

Ferroelectric Properties of Bi3.25La0.75Ti3O12 Thin Films Fabricated Sol-Gel with 2-Step RTA Process

(Ba,Sr)TiO3 Thin Films for Dram’s

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The Inlaid Al₂O₃ Tunnel Switch for Ultrathin Ferroelectric Films

The Inlaid Al₂O₃ Tunnel Switch for Ultrathin Ferroelectric Films

Ferroelectric Properties of Bi_3.25La_0.75Ti₃O₁₂ Thin Films Fabricated Sol-Gel with 2-Step RTA Process