bluuebunny/crossref_metadata_2025 huggingface dataset:
Synthesis of water-soluble conducting polypyrrole with transition-metal tetrasulfonated porphyrins
Authors: Nabid Mohammad Reza , Shamsianpour Mitra , Sedghi Roya , Osati Samira , Safari Nasser
Published: April 2010

A novel catalytic route for the synthesis of a water-soluble and electrically conducting polypyrrole (PPy) in the presence of sulfonated polystyrene (SPS) is presented. Anionic water-soluble transition-metal tetrasulfonated porphyrins (TSPP) were used to catalyze the polymerization. The reactions were carried out with different monomer, catalyst, template and initiator concentrations and the optimum conditions are reported. Also various pH values ranging from 1 to 4 were investigated. The absorbance of the polaron bands at different pH values demonstrates that pH 2 is the best condition for polymerization. Precipitation or "salting out" phenomenon was highly dependent on the mentioned factors. The formation of PPy was confirmed by UV-vis and FT-IR spectroscopy. Cyclic voltammetry (CV) showed that the synthesized polymer has convenient electroactivity. Furthermore, the presence of SPS that serves as a charge-compensating dopant in this complex provides a unique combination of properties such as processability and water solubility.
Alkynyl corroles: synthesis by Sonogashira coupling reaction and the physicochemical properties
Authors: Zhan Hai-Ying , Liu Hai-Yang , Lu Jun , Wang A-Zhong , You Li-Li , Wang Hui , Ji Liang-Nian , Jiang Huan-Feng
Published: April 2010

Alkynyl corroles were synthesized from iodidphenyl corrole precursor by using Sonogashira coupling reaction with or without the presence of copper(I) iodide co-catalyst. The alkynyl group on corrole macrocycle has a significant effect on the photophysical and electrochemical properties of free-base and metal corrole derivatives.
Photoelectrochemical characterization of electrodepositedZnOthin films sensitized by octacarboxymetallophthalocyanine derivatives
Authors: Idowu Mopelola , Loewenstein Thomas , Hastall Andreas , Nyokong Tebello , Schlettwein Derck
Published: April 2010

Hybrid thin films of crystalline zinc oxide ( ZnO ) modified by different octacarboxymetallophthalocyanines (MOCPc) were prepared by the readsorption method. Homogeneously blue or green thin films were formed. The photoelectrochemical characteristics of the electrodes were studied by time-resolved photocurrent measurements. Zinc(II) 2,3,9,10,16,17,23,24-octacarboxyphthalocyanine ( ZnOCPc ) showed considerably large quantum efficiency in sensitization of ZnO , one of the highest quantum efficiencies obtained so far with phthalocyanine-type sensitizers on nanocrystalline ZnO films.
The structures of free-base carbahemiporphyrazines
Authors: Sripothongnak Saovalak , Barone Natalie V. , Çetin Anıl , Wu Ruoqiu , Durfee William S. , Ziegler Christopher J.
Published: April 2010

In this report we present an X-ray crystallographic study of two N -deficient hemiporphyrazines: dicarbahemiporphyrazine (1) and benziphthalocyanine (2). Both compounds can be isolated in multiple crystal forms, and five different solvated forms of macrocycle 1 are presented. Four of the five are non-planar, showing the high degree of flexibility and capacity for hydrogen bonding from solvent to N-H groups in the macrocycle. The remaining structure of 1 is a planar dicationic species that represents a tautomeric form of the macrocycle often seen in metal binding. Four structures of macrocycle 2 are also presented in this report. The structure of 2 is also planar due to the tautomerism of the internal protons, and structural elucidation of this macrocycle reveals the presence of three ionizable protons rather than the expected single proton postulated by Elvidge and Golden.
Discotic liquid crystals of transition metal complexes 42: the detailed phase structures and phase transition mechanisms of two Cub mesophases shown by discotic liquid crystals based on phthalocyanine metal complexes
Authors: Mukai Hidetomo , Yokokawa Miho , Ichihara Masahiro , Hatsusaka Kazuaki , Ohta Kazuchika
Published: April 2010

We found in our previous works that the sandwich-type phthalocyanine-based rare earth metal complexes, bis[2,3,9,10,16,17,23,24-octakis(3,4-dialkoxyphenoxy)phthalocyaninato]lanthanoid(III) ({[( C n O )2 PhO ]8 Pc }2 M, M = Eu and Lu , n = 8–16) (1 and 3), exhibited two thermotropic cubic mesophases, Cub1 and Cub2, together with columnar mesophases. It is rare that the discotic liquid crystalline compounds show the cubic mesophase. We revealed that their symmetries of the lower temperature Cub1 mesophase and the higher temperature Cub2 mesophase were [Formula: see text] and [Formula: see text], respectively. However, their detailed phase structures were not revealed in the previous works. In this work, we have synthesized a series of novel sandwich-type phthalocyanine-based terbium complexes, bis[2,3,9,10,16,17,23,24-octakis(3,4-dialkoxyphenoxy)phthalocyaninato]terbium(III) ({[( C n O )2 PhO ]8 Pc }2 Tb , n = 8–16) (2). Their mesomorphic properties have been investigated using polarization microscope, DSC and temperature-dependent X-ray diffraction techniques. As the result, the present Tb complexes (2) also showed two cubic mesophases, [Formula: see text] and [Formula: see text], together with columnar mesophases, as well as the previous Eu homologs (1) and Lu homologs (3). We have furthermore investigated by using temperature-dependent electronic absorption spectroscopy to reveal their detailed phase structures and phase transition mechanism of these two Cub mesophases. We have revealed that the [Formula: see text] mesophase forms a bicontinuous structure consisting of branched columns like jungle gym, but that the [Formula: see text] mesophase forms a discontinuous structure consisting of short columns like drums that resulted from the cutting off of the branched columns.
Holocene sediments from the Southern Chile Trench: a record of active margin magmatism, tectonics and palaeoseismicity
Authors: Heberer Bianca , Röser Georg , Behrmann Jan H. , Rahn Meinert , Kopf Achim
Published: April 2010

Sedimentology, petrography and the provenance of Holocene sediments from the Southern Chile Trench (36–47°S) were investigated in an integrated approach combining description of a collection of gravity cores, measurements of physical properties, quantitative X-ray petrography and modal analysis. The sediments studied were trench hemipelagic sediments, fan deposits, and more distal hemipelagic sediments from the Nazca Plate. The trench is mostly fed by multiple point sources via submarine canyons. Sandy turbidites show a southward increase in sediment maturity. Whereas volcanic lithic fragments and plagioclase represent the dominant fraction in the north, quartz content strongly increases in the southern part of the study area, in line with source lithologies. Further north, active volcanoes in the Main Cordillera represent almost the entire provenance signal as a result of a strong contribution of highly erodible volcanic rocks. Recurrence rates of sandy and silty turbidites in the trench fan sediments indicate a link to the palaeoseismic record on land. Our study documents the potential usefulness of proximal turbidites to reconstruct palaeoseismicity, even at a scale of single segments of the plate boundary.
Multiple high-pressure metamorphic events and crustal telescoping in the NW Highlands of Scotland
Authors: Storey C.D. , Brewer T.S. , Anczkiewicz R. , Parrish R.R. , Thirlwall M.F.
Published: April 2010

The Glenelg–Attadale Inlier is the largest basement inlier within the Caledonian orogen in NW Scotland. A Western Unit consists of trondhjemite–tonalite–granodiorite (TTG) gneisses and subordinate mafic intrusions with locally preserved mafic high-pressure granulite and eclogite assemblages. An Eastern Unit comprises TTG gneisses, Grenville-age (
c
. 1.1 Ga) eclogite and metasediments. U–Pb zircon ages from the Western Unit TTG gneisses are highly disturbed with Neoarchaean upper intercepts and Palaeo- to Mesoproterozoic lower intercepts, suggesting strong reworking at these times. U–Pb zircon, Sm–Nd and Lu–Hf garnet–clinopyroxene dates from the Western Unit high-pressure granulite and eclogite yield Neoarchaean (
c
. 2.6–2.8 Ga) and Palaeoproterozoic (
c
. 1.75 Ga) ages, respectively. These ages correspond to the ages of partial resetting of the TTG gneisses. The eclogite in the Western Unit may represent the high-pressure convergent margin to the lower-pressure Laxfordian events within the Lewisian Gneiss Complex, whereas the Mesoproterozoic eclogites in the Eastern Unit may represent a farther eastward Grenville-age margin. Further east, Ordovician high-pressure granulites within the Moine Supergroup may represent another, later, Grampian convergent margin. These high-pressure belts were developed sequentially towards the east and telescoped westwards from Palaeoproterozoic to Early Palaeozoic times.

Supplementary material:

U–Pb analytical data and LA-ICP-MS trace element data are available at
http://www.geolsoc.org.uk/SUP18389
.
Large submarine slides on a steep continental margin (Camamu Basin, NE Brazil)
Authors: Cobbold Peter R. , Gilchrist Gil , Scotchman Iain , Chiossi Dario , Chaves Fabiana Fonseca , Souza Fernando Gomes De , Lilletveit Ragnhild
Published: April 2010

We describe a set of thin-skinned structures from the offshore Camamu Basin. The margin is about 40 km wide and the sea floor has a slope of up to 10%. The sedimentary cover is up to 7 km thick. Neocomian strata accumulated during continental rifting. Aptian strata consist mainly of coarse clastic sediment and evaporite. Late Cretaceous strata are thin or absent and the Tertiary succession is about 1 km thick, above a prominent Eocene unconformity. The Neocomian and Aptian sequences contain abundant thin-skinned structures, which are extensional near the continental shelf and compressional toward the toe of the slope. The structures have detached on Aptian evaporite and on the base of Neocomian shale. One giant slide is about 5 km thick and 60 km wide. It displays mirror symmetry about a vertical plane perpendicular to the margin, as occurs in physical models. The main phase of sliding occurred between the Campanian and the middle Eocene. The trigger may have been a regional phase of uplift and exhumation, for which there is independent evidence on the shelf and inland.
Two-scale gravitational collapse in the Amazon Fan: a coupled system of gravity tectonics and mass-transport processes
Authors: Reis A.T. , Perovano R. , Silva C.G. , Vendeville B.C. , Araújo E. , Gorini C. , Oliveira V.
Published: April 2010

Gravity tectonics affects the entire marine sedimentary sequence of the Foz do Amazonas basin, including the topmost Amazon Fan. During the various stages of the margin's evolution, the sedimentary loading and bathymetric slope induced the formation of a linked extensional–compressional system in which gravitational fold-and-thrust belts form significant structural features on the continental slope. Seismic analysis carried out in this study shows that sea-floor relief created along these thrust belts can trigger recurrent mass-transport deposits in the upper–middle Amazon Fan, suggesting a long-lasting linkage between gravity tectonics and mass-transport processes throughout the sedimentary evolution of the Amazon Fan.

Supplementary material:

Uninterpreted seismic sections are available at
http://www.geolsoc.org.uk/SUP18393
.
Structural evolution and sediment entrainment in mass-transport complexes: outcrop studies from Italy
Authors: Butler R.W.H. , McCaffrey W.D.
Published: April 2010

Mass-transport complexes (MTCs) form a significant component of many deep marine clastic successions. Here, studies of outcrop examples of MTCs from the Italian Apennines indicate that material can be entrained across both the upper and lower boundaries of a mass flow. The studied MTCs all incorporate debrite–turbidite couplets. Growth stratal geometries in the overlying turbidite sandstones indicate that turbidite deposition occurred synchronously with internal deformation within substrate debris flows. The turbidite stratal patterns and the internal structure of the debrites jointly indicate that at least the later stages of MTC emplacement were ordered, involving coherent creep. This process can generate unexpected sand-on-sand juxtapositions across otherwise low-permeability debritic horizons. Entrainment of substrate material across the lower debris-flow boundary occurred by thrusting, although this deformation can have initiated before the arrival of the further-travelled debris flow itself. The outcrop examples are thus characterized by composite deformation and depositional histories, such that different parts of composite MTCs can have experienced radically different amounts of displacement. The ordered creeping deformation recognized at outcrop may, however, be under-recognized in seismic examples, where internal deformation and associated growth stratal geometries are less easy to study.
Continental margin shale tectonics: preliminary results from coupled fluid-mechanical models of large-scale delta instability
Authors: Ings Steven J. , Beaumont Christopher
Published: April 2010

We investigate the evolution of rifted continental margin shale tectonics using 2D finite-element models that couple sediment deformation to compaction-driven Darcy fluid flow via the effective stress. Fluid overpressures are generated in the models by a combination of mechanical compaction (grain rearrangement) and viscous compaction (grain dissolution and local reprecipitation), and lead to failure and flow of visco-plastic Bingham shale. Model results indicate that pore fluid pressures must be 90–95% of the lithostatic pressure to cause shale failure and delta destabilization. Mechanical compaction alone is insufficient to generate fluid overpressures required for failure in the models and viscous compaction is the primary source. The numerical models include delta progradation, lateral lithology variation, and flexural isostatic compensation. Seaward shale flow and associated overburden deformation results in the formation of landward regional and counter-regional fault-bounded extensional basins, a transitional domain of thickened and folded shale beneath the continental slope, and a seaward fold and thrust belt at the delta toe. The structural styles generated by the preliminary numerical models are compatible with features observed in unstable Cenozoic deltas (e.g. the Niger Delta) and provide additional insight into the fundamental relationships between deltaic sedimentation, fluid pressure generation, and margin-scale gravity spreading.
Tracers of uplift and subsidence in the Cape Verde archipelago
Authors: Ramalho R. , Helffrich G. , Schmidt D.N. , Vance D.
Published: April 2010

Ocean islands are subject to vertical movements through their lifetime and these movements' origins are poorly understood. Tracking island freeboard provides insight into the mechanisms that cause these movements. The Cape Verde archipelago is the result of hotspot volcanism ranging from 26 Ma to the present, and constitutes a structural pile that has preserved a record of the palaeo-positions of mean sea level. These palaeo-markers, both sedimentary and volcanic, are datable and can be used to track the island's history of vertical movements when used in conjunction with a eustatic curve. We have studied the volcanostratigraphy of Cape Verde and mapped the palaeo-marker positions and features, and we provide the sea-level height information that can be estimated through them. Evidence exists for differential uplift histories throughout the archipelago, with substantial uplift in some of the islands synchronous with volcanism. Other islands, in contrast, exhibit evidence for stability or complex uplift–subsidence histories.

Supplementary material:

Detailed island geology information is available at
http://www.geolsoc.org.uk/SUP18390
.
Controls on the stratigraphic development of the Triassic Fundy Basin, Nova Scotia: implications for the tectonostratigraphic evolution of Triassic Atlantic rift basins
Authors: Leleu Sophie , Hartley Adrian J.
Published: April 2010

The Late Triassic synrift succession of the Minas sub-basin (Bay of Fundy, Nova Scotia) includes a fluvio-alluvial fan-dominated unit (lower and middle Wolfville Formation), a transitional fluvio-playa unit (upper Wolfville Formation) and an upper playa-dominated package (Blomidon Formation). We describe the facies development in the 240 m thick upper Wolfville Formation, examine vertical facies stacking patterns and develop a depositional model for this succession. The unit comprises channelized and unconfined fluvial deposits interbedded with aeolian and playa sediments that grade upward into playa deposits. The succession comprises progradational and retrogradational fluvial packages and thin aggradational playa claystones. Comparison with 11 other Atlantic margin continental Triassic rift basins allows an assessment of the controls that govern rift basin development. The transition from fluvial to playa or lacustrine conditions occurs in all basins at different times. The lack of synchronicity indicates that global climate change was not a controlling factor. We suggest that the fluvial to lacustrine or playa transition was due to a decrease in source area relief related to a decline in regional tectonic activity, and that the basin was hydrologically closed throughout sedimentation. This tectonostratigraphic model may be appropriate for other Triassic basins developed along the Atlantic margin.
The Oyut Ulaan Volcanic Group: stratigraphy, magmatic evolution and timing of Carboniferous arc development in SE Mongolia
Authors: Blight James H.S. , Petterson Michael G. , Crowley Quentin G. , Cunningham Dickson
Published: April 2010

The Palaeozoic–Mesozoic tectonic evolution of Central Asia, including the vast terrane collage that makes up Mongolia, has been a topic of considerable debate. The Oyut Ulaan Volcanic Group is a sequence of volcanic and sedimentary rocks in SE Mongolia that forms the southern part of the Devonian–Permian Saykhandulaan Inlier. Fieldwork traverses and mapping have established four distinct formations in the Oyut Ulaan Volcanic Group that record the nature of arc activity in part of the Central Asian Orogenic Belt during the Carboniferous. Physical volcanological and sedimentological characteristics of the four formations suggest three clear eruptive styles: (1) periodic andesite volcanism in an actively eroding arc setting that also contained large rivers and swamps; (2) highly effusive plateau andesite volcanism; (3) explosive rhyolitic effusion. Geochemical analyses of volcanic lithologies suggest that the group represents subduction-related, mature, continental arc volcanism. Geochemical results document an evolving magma system to which surface processes of the volcano-sedimentary model may be linked. Magma pulses and replenishments are identified from variations in chemostratigraphy. Newly obtained zircon ages from the volcanic succession fix its emplacement (eruption) at 323.0 ± 0.7 Ma (mid-Carboniferous or late Mississippian). A granite cobble from the lower part of the Oyut Ulaan Volcanic Group gives a U–Pb zircon age of 338.9 ± 0.4 Ma indicating that arc plutons were emplaced 10 Ma prior to the Oyut Ulaan volcanism and were eroded soon after. Our work provides timing constraints for final accretion and continental assembly in SE Mongolia, and also sheds light on the petrological development of a magmatic arc system within an evolving accretionary orogen.
Early Cretaceous radiolarians from the Spongtang massif, Ladakh, NW India: implications for Neo-Tethyan evolution
Authors: Baxter Alan T. , Aitchison Jonathan C. , Ali Jason R. , Zyabrev Sergey V.
Published: April 2010

The discovery of two Early Cretaceous (mid-Valanginian–mid-Aptian range) radiolarian faunal assemblages from ribbon-bedded cherts collected near Photoskar in northern Ladakh, NW India, provides the first robust biostratigraphic age constraints associated with the Spongtang massif. This klippe of relict Neotethyan suprasubduction-zone ophiolitic rocks and related arc volcanic rocks crops out 30 km south of the Indus suture in Ladakh. The radiolarian assemblages, the age assignment of which lies between published radiometric ages, provide new constraints on the evolution of this intra-oceanic island arc system. Critically, from them it can be inferred that the system was appreciably long-lived (Jurassic–Cretaceous) and more continuous than is commonly considered.
Detrital zircon SHRIMP U–Pb age study of the Cordillera Darwin Metamorphic Complex of Tierra del Fuego: sedimentary sources and implications for the evolution of the Pacific margin of Gondwana
Authors: Hervé F. , Fanning C.M. , Pankhurst R.J. , Mpodozis C. , Klepeis K. , Calderón M. , Thomson S.N.
Published: April 2010

The Cordillera Darwin Metamorphic Complex in the southernmost Andes includes a basement of probable Palaeozoic age, a mid-Jurassic and younger volcano-sedimentary cover, and a suite of Jurassic granites, all of which were jointly metamorphosed during the Cretaceous. Detrital zircon ages presented here show that some of the amphibolite-facies metamorphic rocks previously mapped as basement have a Jurassic protolith. Overall the detrital zircon age patterns for samples of the Cordillera Darwin basement differ from those of the Madre de Dios Terrane of the western Patagonian Andes with which they had been correlated; instead, they are more comparable with those from the Eastern Andes Metamorphic Complex, which apparently developed in a passive margin setting. The paucity of Cambrian detrital zircons indicates that the meta-igneous basement of the Magallanes foreland basin of central and northern Tierra del Fuego was not the main source of detritus for the protolith of the Cordillera Darwin Metamorphic Complex. The possibility is envisaged that the Magallanes Fagnano transform fault boundary between the Scotia and South America plates resulted from reactivation of an older, pre-Jurassic suture zone between the basement terranes of north–central Tierra del Fuego and Cordillera Darwin.

Supplementary material:

Geographical coordinates of analysed samples, sensitive high-resolution ion microprobe U–Th–Pb analytical data and representative cathodoluminescence images of zircon grains analysed are available at
http://www.geolsoc.org.uk/SUP18397
.
Laurentian origin of the Ordovician Grangegeeth volcanic arc terrane, Ireland
Authors: McConnell Brian , Crowley Quentin G. , Riggs Nancy
Published: April 2010

U–Pb ages determined by laser-ablation multi-collector inductively coupled plasma mass spectrometry on 199 zircons from a lithic pumice tuff are the first isotopic ages from the Grangegeeth volcanic terrane of Ireland. The youngest zircon population (
n
= 24) yields an age of 465.4 +2.4/−3.1 Ma. Inherited zircons yield ages of
c
. 1120–1520,
c
. 1650–1914 and
c
. 2540–2890 Ma. The absence of zircons between
c
. 550 and 700 Ma argues against involvement of Avalonia as a source of inherited crystals. Overall, the inherited age spectra are characteristic of Laurentian crust or metasedimentary successions of peri-Laurentian provenance. These findings suggest that the Grangegeeth volcanic terrane does not represent a continuation of the intra-Iapetus Exploits arc of Newfoundland.

Supplementary material:

Full analytical protocols, applied data corrections, processing and plotting rationales and data table for zircon LA-MC-ICP-MS analysis are available at
http://www.geolsoc.org.uk/SUP18399
.
(Invited) Changing Front-End Dielectric Requirements for End-of-the-Roadmap CMOS and Beyond
Authors: Register Leonard F. , Basu Dipanjan , Hasan Mohammad , Reddy Dharmendar , Shi Ningyu , Banerjee Sanjay
Published: April 2010

Front-end dielectric requirements for end-of-the roadmap CMOS and beyond are considered. For the former, we focus on the surface-roughness limited channel mobility and short channel device performance, and on how use of alternative dielectric gate stacks with perhaps larger surface roughness might affect short channel device performance. We find that surface-roughness limited channel mobility can be a misleading predictor of short channel device performance, and, in particular, that perhaps increased surface roughness associated with use of high-k dielectrics may be far less problematic than channel mobility measurements would suggest. Dielectric requirements for two beyond CMOS device concepts, the heterobarrier tunnel FET (HetTFET) and the even more exotic graphene bilayer psuedo-spin FET (BiSFET) are also considered. While these latter devices may or may not ultimately work as hoped, they serve to illustrate how the demands on front-end dielectrics could change radically with emerging technologies, and indeed, how the emergence of beyond CMOS devices could depend critically on advances in dielectric technology.
(Invited) High-k Gate Dielectrics for Nanoscale CMOS Devices: Status, Challenges, and Future
Authors: Park Dae-Gyu , Wang Xinlin
Published: April 2010

This paper describes historical efforts of replacing SiO2 by high-k dielectric, and an implementation of high-k/metal gate (HK/MG) gate stack into the product level of industry standard low power bulk technology and high performance silicon-on-insulator (SOI) complementary metal-oxide-semiconductor (CMOS) devices. HK/MG stack provides further device scaling in channel length and inversion thickness (Tinv), leading to enable contact gate pitch scaling. Mobility degradation with Tinv scaling and threshold voltage (Vt) variability due to random telegraph noise and random dopant fluctuations at 15nm node and beyond are discussed, followed by outlook of future generation CMOS devices.
(Invited) ALD High-k as a Common Gate Stack Solution for Nanoelectronics
Authors: Ye Peide , Gu Jiangjiang , Wu Yanqing , Xu Min , Xuan Yi , Shen Tian , Neal Adam
Published: April 2010

The scaling of silicon-based MOSFET technology beyond the 22 nm node is challenging. Further progress requires new materials, innovative structures, and even novel device concepts. All the emergent channel materials need perfect top-gate dielectric stacks in order to sustain their potential device performance. ALD high-k as a common gate stack solution finds itself very successfully integrated with these novel channel materials such as Ge, III-V, different nanowires, carbon nanotubes (CNTs), graphene and newly discovered all oxide electronic materials.
(Invited) Towards the Ultimate Scaling of MOSFET Gate Dielectrics: Direct Contact of High-k and Silicon
Authors: Ahmet Parhat , Kakushima Kuniyuki , Iwai Hiroshi
Published: April 2010

In this paper, we report our approaches in realizing high-k/Si interface without SiOx based interfacial layer by introducing Lanthanum silicates as the interfacial layer at the high-k dielectric and Si interface. We also demonstrated the usefulness of 'Direct Contact' of high-k with Si through a lanthanum silicate interlayer in the scaling of EOT beyond 0.5nm.
(Invited) Quantitative Correlation Between Low-Field Mobility and High-Field Carrier Velocity in Quasi-Ballistic-Transport MISFETs with High-k Gate Dielectrics
Authors: Tatsumura Kosuke , Goto Masakazu , Kawanaka Shigeru , Kinoshita Atsuhiro
Published: April 2010

Mobility (mob) and Lg dependence of high-field velocity (v) is systematically investigated. A wide variety of mob characteristics is realized with various gate dielectrics of SiO2, SiON, HfLaSiON, and HfLaAlSiON. At Lg=30nm, the sensitivities of v to mob and scaling in Lg, (dv/v)/(dmob/mob) and (dv/v)/(dLg/Lg), are 0.43 and -0.45, respectively: in quasi-ballistic transport regime, mob and scaling in Lg still play an important role on Ion improvement with v enhancement. High-k MISFETs do not show any particular v degradation in high-energy carrier transport. Mob-Tinv characteristics required for sub-22nm-node high-k gate-stacks are discussed based on the experimental data for mob and Lg dependence of v.
(Invited) Electrical Scanning Probe Microscopy Techniques for the Detailed Characterization of High-k Dielectric Layers
Authors: Rommel Mathias , Yanev Vasil , Paskaleva Albena , Erlbacher Tobias , Lemberger Martin , Bauer Anton J. , Frey Lothar
Published: April 2010

The use of scanning probe microscopy (SPM) techniques for the electrical characterization of high-k dielectric layers is reviewed, focusing on conductive atomic force microscopy (cAFM) and scanning capacitance microscopy (SCM). It is demonstrated exemplarily for ZrO2 high-k layer stacks that cAFM enables a detailed analysis of the morphological and electrical layer characteristics. Film morphologies can be determined even for surfaces where topography mapping can not detect distinct surface roughness like grain structures. For as-deposited amorphous layers, the current distribution is random whereas increased leakage currents at grain boundaries can be observed for nano-crystalline samples. The dominant current mechanisms through the layers can be determined from current voltage curves at distinct local points. Comparison with conventional techniques proofs the findings by cAFM. The quantitative interpretation of SCM measurement results often suffers from parasitic capacitances and light induced effects. Local thickness variation of dielectrics, however, can be detected very sensitively.
(Invited) Electrical Characterization of Ge-pFETs with HfO2/TiN Metal Gate: Review of Possible Defects Impacting the Hole Mobility
Authors: Mitard Jerome , Vincent Benjamin , De Jaeger Brice , Krom Raymond , Loo R. , Eneman Geert , DeMeyer Kristin , Meuris Marc , Heyns Marc , Vandervorst W. , Caymax Matty , Hoffmann Thomas
Published: April 2010

Recently, best 65 nm Ge pMOSFET performance has been reported with a standard Si CMOS HfO2 gate stack module (1). In this contribution, we investigated in more detail how device performance, especially the hole mobility, depends on the characteristics of layers featuring the gate dielectric (HfO2, SiO2 and the Si cap layer). We found that many point defects are involved in the mobility control. We specifically highlight the role of defects linked to the Si cap integration. A critical Si thickness is also extracted, separating two important regimes. We finally report the difference in hole-mobility-limiting mechanisms between Ge devices integrating two different Epi-Si passivation schemes. Based on low temperature measurements, the promising Si3H8 process shows an additional coulomb scattering mechanism compared to SiH4.
(Invited) Investigation of High-κ/InxGa1-xAs Interfaces
Authors: Cherkaoui Karim , O'Connor Eamon , Monaghan Scott , Long Rathnait D. , Djara Vladimir , O'Mahony A. , Nagle R. , Pemble Martyn E. , Hurley Paul K.
Published: April 2010

The quality of the high-k/InxGa1-xAs interface is a crucial factor in achieving high electron mobility compound semiconductor field effect transistors. Capacitance and conductance characterisation methods were employed to evaluate different high-k/InGaAs interfaces. This paper will first discuss the specificity of capacitance voltage characteristics of compound semiconductor MOS structures, and then the recent progress in the study of high k/InxGa1 xAs interfaces will be presented. The capacitance and conductance measurements are combined to provide a picture of the interface state density. We have also investigated the merit of using intermediate k value dielectrics such as Al2O3 and MgO as interface control layers between the semiconductor and the main high k layer.
(Invited) Dielectric Properties and Flat-Band Voltages of Doped- HfO2 Thin Films
Authors: Ducroquet Frederique , Rauwel Erwan , Brizé Virginie , Dubourdieu Catherine
Published: April 2010

The control of high-symmetry phases of HfO2 can be achieved by cationic substitution for Hf. The electrical properties of the cubic HfO2 phase stabilized by addition of yttrium or magnesium were investigated. The introduction of moderate Y or Mg doping content (~10-15%) in HfO2 results in an enhancement of the dielectric constant. No degradation of the interface state density and of the leakage current was noticed. The flat-band voltage is shifted to positive voltages, similarly as it was observed for monoclinic and cubic pure HfO2 thin films. This result confirms that the contribution of the SiO2/high-k interface to the flat-band voltage depends on the structural interface properties.
Experimental Demonstration of Higher-k Phase HfO2 Through Non-Equilibrium Thermal Treatment
Authors: Nakajima Yasuhiro , Kita Koji , Nishimura Tomonori , Nagashio Kosuke , Toriumi Akira
Published: April 2010

Structural phase transformation of pure-HfO2 films in higher-k phase (cubic or tetragonal phase) was investigated. HfO2/SiO2/Si stacks were annealed at 600oC under various temperature programs. We found that the peak intensity ratio of the higher-k phase to monoclinic one in XRD was enhanced distinctly by increasing the ramping-up rate of temperature, even though the equilibrium phase at 600oC should be the monoclinic. Additionally, the ratio gradually decreased with extending the annealing time, but the higher-k phase was maintained by annealing after deposition of Si capping-layer on HfO2/SiO2/Si stacks.
(Invited) Variability and Reliability in Ultra-Scaled MOS Devices: How Should They Be Evaluated from Nanoscale to Circuit Level?
Authors: Nafría Montserrat , Rodríguez Rosana , Porti Marc , Martín-Martínez Jarvier , Lanza Mario , Aymerich Xavier
Published: April 2010

Intrinsic process variability and aging mechanisms will strongly affect circuit performance and reliability, so that they need to be considered during the design phase. In this paper, the approaches adopted at UAB to evaluate the nanoscale sources of device variability related to the MOSFETs gate oxide and to include device variability and aging during circuit simulation are described. First, the Conductive Atomic Force Microscope is used to evaluate the impact of processing on the morphological and electrical properties of the gate oxide at the nanoscale. As example, the impact of thermal annealing at different temperatures on the electrical properties of Al2O3/SiO2 stacks is analyzed. Second, a reliability circuit simulation methodology, which combines Montecarlo and SPICE simulations, is presented to transfer the variability and aging effects in devices up to circuit level. The methodology is applied to evaluate the impact of threshold voltage time-dependent variability in differential amplifiers performance and reliability.
(Invited) Negatively Charged Defects Generated by Rare-Earth Materials Incorporation into HfO2 and the Impact on the Gate Dielectrics Reliability
Authors: Sato Motoyuki , Kamiyama Satoshi , Sugita Yoshihiro , Matsuki Takeo , Morooka Tetsu , Suzuki Takayuki , Shiraishi Kenji , Yamabe Kikuo , Yugami Jiro , Ikeda Kazuto , Ohji Yuzuru , Ohmori Kenji , Yamada Keisaku
Published: April 2010

We studied the impact of Yttrium and Lanthanum incorporation into HfO2 on reliability (TDDB, PBTI and 1/f noise). They introduce smaller Weibull β values and early failure in TDDB, with negative shift in PBTI. They are caused by the negatively charged interstitial oxygen defect generated by Yttrium and Lanthanum incorporation. The effect of Lanthanum is larger than that of Yttrium. It can be explained by the larger ion radius and molecular volume of La2O3 than Y2O3. On the other hand, they are effective in noise reduction, as an effect of interface state density reduction. The key point in fabricating low Vth and highly reliable MOSFETs is the technology for suppression of this interstitial oxygen defect generation.
(Invited) Degradation in HfSiON Film Induced by Electrical Stress Application
Authors: Hasunuma Ryu , Tamura Chihiro , Nomura Tsuyoshi , Kikuchi Yuuki , Ohmori Kenji , Sato Motoyuki , Uedono Akira , Chikyow Toyohiro , Shiraishi Kenji , Yamada Keisaku , Yamabe Kikuo
Published: April 2010

The dielectric degradation under electrical stress application was attributed to generation of oxygen vacancy Vo, and structural transformation" in HfSiON films, in addition to widely known charge trapping. The former two result from ion drift under electrical field due to its ionic character of Hf-based dielectrics. While Vo generation and charge trapping are atomic-range phenomena, it is surprising that long-range structural transformation can also occur under electrical filed before dielectric breakdown even at room temperature. The transformation is derived by intensive mass transport in the dielectric film, thereby can not be annealed out.
(Invited) Statistical Low-Frequency Noise Model for MOSFETs under Large Signal Cyclo-Stationary Excitation
Authors: Wirth Gilson , Da Silva Roberto , Srinivasan P. , Brederlow Ralf
Published: April 2010

Experimental investigation and statistical modeling of the low frequency noise behavior of MOSFETs under cyclo-stationary excitation was performed. The developed modeling approach is based on discrete device physics quantities, which are shown to cause statistical variability in LF noise behavior. It allows the derivation of an analytical formulation for the noise behavior. Monte Carlo simulations were also performed. Good agreement between experimental data, Monte Carlo simulations and model is found.
(Invited) An Electron-Beam-Induced Current Investigation of Electrical Defects in High-k Gate Stacks
Authors: Chen Jun , Sekiguchi Takashi , Fukata Naoki , Takase Masami , Nemoto Yoshihiro , Hasunuma Ryu , Yamabe Kikuo , Sato Motoyuki , Yamada Keisaku , Chikyow Toyohiro
Published: April 2010

We succeeded in applying electron-beam-induced current (EBIC) technique to visualize the current leakage sites in the MOS devices with HfSiON gate dielectrics. The occurrence of initial leakage sites in fresh devices has been investigated with consideration of the effects of well type, gate size and gate electrode. Stress-induced leakage and breakdown sites were studied by in situ voltage stress and EBIC characterization. Finally, the micro-structure and physical damages at various leakage sites were characterized by TEM. Based on the EBIC and TEM results, the leakage and breakdown mechanisms of HfSiON gate stacks were discussed.
Resistive Switching Behaviors of NiO Bilayer Films with Different Crystallinity Layers
Authors: Kita Koji , Eika Atsushi , Nishimura Tomonori , Nagashio Kosuke , Toriumi Akira
Published: April 2010

From the studies on the resistive switching of NiO bilayer films consisting of different degree of crystallinity, it was observed that the initial I-V characteristics were depending on the bias polarity and the forming process was significantly asymmetric. The well-crystalline NiO film shows resistive switching whereas poorly-crystalline film does not. For the bilayer stack of those two kinds of films, the forming voltage becomes lower and has less variety when the well-crystalline side is positively-biased. This result suggests that the forming voltage and currents are controllable by modifying the film properties on the metal-oxide interfaces.
Correlation of Negative Bias Temperature Instability and Breakdown in HfO2/TiN Gate Stacks
Authors: Rahim Nilufa , Misra D.
Published: April 2010

Both negative bias temperature instability (NBTI) and time dependent dielectric breakdown (TDDB) are two major reliability issues for long term performance of high-k gate stacks. In this work, these two degradation mechanisms were extensively analyzed to explore any possible correlation in terms of defects formation. A variety of dielectric stacks were considered to perform NBTI and TDDB. It was observed that NBTI induced defects, generated at the interface and in the interfacial layer were somewhat identical to the defects that dominate the breakdown process.
Reliability Characteristics of D2O-Radical Annealed ALD HfO2 Dielectric
Authors: Tu Chia-Hao , Chiu Fu-Chien , Chen Chun-Heng , Hou Cheng-Hao , Lee Zi-Jay , Chen Hung-Wen , Chen Shuang-Yuan , Huang Heng-Sheng , Wu Tai-Bor , Hwang Huey-Liang
Published: April 2010

In this work, metal-oxide-semiconductor (MOS) capacitors incor-porating D2O-radical annealed atomic-layer-deposition (ALD) HfO2 gate dielectric were fabricated and investigated. The thermo-chemical breakdown model (E model) is used to analyze the TDDB characteristics for lifetime projection. TDDB data shows that Weibull slope (β) is increased with increasingly stress tem-perature. This may come from the temperature sensitive defects and possible redistribution in dielectric. Meanwhile, the Weibull slope is independent of the stress voltage. Based on the TDDB data, the activation energy (Ea), active dipole-moment (p0) electric-field acceleration factor (γ) and electric field at 10 years lifetime (E10years) of the D2O-radical annealed ALD HfO2 thin films were obtained.
The Degradation of Thin Silicon Dioxide Films Subjected to Pulse Voltage Stresses at Nanoscale
Authors: Wu You-Lin , Lin Jing-Jenn , Chang Sheng-Hsiang , Huang Chiung-Yi
Published: April 2010

In this paper, we report the observation of the degradation and breakdown of thin silicon dioxide films subjected to both the unipolar and bipolar pulse voltage stresses at nanoscale by using conductive atomic force microscopy. It is found that the unipolar pulse voltage stress produces more severe damage than does the bipolar pulse voltage stress. We also notice that hard breakdown is always preceded by soft breakdown for thin silicon dioxide subjected to either unipolar or bipolar pulse voltage stress, and the soft breakdown is always accompanied with random current fluctuation in the I-t characteristics. The influence of varying frequency of the pulse voltage stresses on the oxide breakdown is also investigated in this work.
Suppression Mechanism of Volume Shrinkage for SOG Film by Plasma Treatment
Authors: Nagata Kohki , Kosemura Daisuke , Takei Munehisa , Akamatsu Hiroaki , Hattori Maki , Koganezawa Tomoyuki , Machida Masatake , Son Jin-Young , Hirosawa Ichirou , Nishita Tatsuo , Shiozawa Toshihiko , Katayama Daisuke , Sato Yoshihiro , Hirota Yoshihiro , Ogura Atsushi
Published: April 2010

We investigated the suppression mechanism of volume shrinkage for a spin on glass (SOG) film by plasma treatment using hard X-ray photoelectron spectroscopy, X-ray reflectometry (XRR), and UV-Raman spectroscopy. The suppression of the SOG film shrinkage was attributed to the control of N out-diffusion from the SOG film and O in-diffusion into the SOG film, which was due to the plasma treatment prior to the conventional cure annealing process. It was also confirmed from the XRR measurements that the SOG film was densified by the plasma treatment. Moreover, UV-Raman measurements were performed to evaluate the Si stress at the SiO2/Si interface that was induced during the gap filling process. The stress was controlled by the appropriate plasma treatment. Thus, we concluded that the plasma treatment was effective for the suppressions of SOG film shrinkage and stress induction and for the SOG film densification.
How to Evaluate Surface Free Energies of Dense and Ultra Low-κ Dielectrics in Pattern Structures
Authors: Oszinda Thomas , Schaller Matthias , Dittmar Kornelia , Jiang Le , Schulz Stefan E.
Published: April 2010

A method to evaluate the surface free energy in pattern structure, of chemical vapor deposited dense and ultra low-κ (ULK) SiOCH dielectric films, is presented. Therefore dense and ultra low-κ films were treated by different post ash plasma processes. This films were characterized using Auger electron spectroscopy, atomic force microscopy and contact angle measurements. For both material systems a correlation between the amount of surface near carbon and the surface free energy was found, independent on the plasma chemistry used. The range of the surface roughness is very small and does not have a strong impact on the surface free energy. The correlation model can be applied for pattern structures. After measuring the carbon concentration at the side walls by methods like TEM-EELS or XPS the model provides the polar and dispersive part of the surface free energy. Having the surface free energy, contact angle of different liquids on or in pattern structures can be calculated. Hence, the wetting behavior and the probability of pattern collapse can be predicted, which is essential to select an appropriate chemical for cleaning and other wet chemical based processes.
Ultra-Thin (AlCrTaTiZr)Nx/AlCrTaTiZr Bilayer Structures of High Diffusion Resistance to Cu Metallization
Authors: Chang Shou-Yi , Chen Dao-Sheng
Published: April 2010

In this study, (AlCrTaTiZr)N0.7 and (AlCrTaTiZr)N1 films of only 10 nm thick have been developed as diffusion barrier materials for Cu interconnects. An AlCrTaTiZr buffer layer of 5 nm thick was deposited on these barriers to form (AlCrTaTiZr)N0.7/AlCrTaTiZr and (AlCrTaTiZr)N1/AlCrTaTiZr bilayer structures, as well as to improve the interface adhesion to Cu layers. The as-deposited AlCrTaTiZr and (AlCrTaTiZr)N0.7 films were amorphous, while the (AlCrTaTiZr)N1 was observed as a nanocomposite structure with nanocrystallites embedded in an amorphous matrix. At a high temperature of 800oC, Cu began to penetrate into the AlCrTaTiZr buffer layer, but its diffusion was retarded by the (AlCrTaTiZr)N0.7 and (AlCrTaTiZr)N1 barriers. At an extremely high temperature of 900oC, the interdiffusion of Si and Cu atoms occurred through the (AlCrTaTiZr)N0.7/AlCrTaTiZr bilayer, and Cu silicides formed; whereas the (AlCrTaTiZr)N1/AlCrTaTiZr bilayer remained stable. No interdiffusion through the (AlCrTaTiZr)N1/AlCrTaTiZr bilayer or formation of any silicides was identified, indicating an excellent diffusion resistance.
A Mechanism for Increasing Growth Rate of Undoped SACVD Film
Authors: Sokolov Yuri V. , Harrison Judy , Harward Briant
Published: April 2010

Sub-atmospheric SACVD undoped silicon glass (USG) inter-metal dielectric films, while having a high trench-filling ability, have a low deposition rate. At high deposition temperature and pressure, commonly recommended, however, TEOS gas precursor is fairly consumed in the gas-phase reactions without contributing to deposition on the substrate. Two growth mechanisms of the USG film are discussed. One is a direct TEOS -O3 reaction on the Si surface and another one is a result of reaction of the intermediates, which can contribute to the growing SiO2 from the gas-phase. This study targets the deposition conditions where TEOS contributes to growing SiO2 film from both the gas phase and the surface chemisorptions. This approach helps to use TEOS efficiently, to maximize the deposition rate of USG while leaving good SiO2 film quality. The film's morphology, wet etch rate, and shrinkage that are related to the film's flow capability are also discussed.
(Invited) Atomistic Guideline for MONOS-Type Memories with High Program/Erase Cycle Endurance
Authors: Yamaguchi Keita , Shiraishi Kenji , Otake Akira , Kobayashi Kenji
Published: April 2010

We have proposed atomistic guiding principles for high program/erase (P/E) cycle endurance MONOS type memories based on first principles calculations. We found that excess O atoms near the SiN/SiO2 interfaces are the cause of memory degradation due to an irreversible structural change during P/E cycles. These results indicate that by suppressing excess O atoms the MONOS characteristics can be effectively improved. Moreover, we proposed that a defect with Jahn-Teller type structural changes is one of the most suitable traps for charge trap memories, since Jahn-Teller distortion is essentially reversible during P/E cycles with very little degradation.