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Steinau an der Straße, Germany

Schroeder U.,NaMLab gGmbH | Martin D.,NaMLab gGmbH | Mueller J.,Fraunhofer Center for Nanoelectronic Technologies | Yurchuk E.,NaMLab gGmbH | And 6 more authors.
ECS Transactions

The ferroelectric behavior of capacitors based on hafnium oxide dielectrics will be reported. Thin films of 6-30 nm thickness were found to exhibit ferroelectric polarization-voltage hysteresis loops when integrated into TiN-based metal-insulatormetal capacitors. A remanent polarization up to 25 μC/cm2 and a high coercive field of about 1 MV/cm was observed. Doping of HfO2 by different dopants with an atomic radius ranging from 110 nm (Si) to 188 nm (Gd) was evaluated and in all cases ferroelectric behavior was verified by P-V hysteresis, small signal capacitance-voltage, and for Si by piezoelectric measurements. Polarization retention showed no significant decay within a measurement range of up to two days. © The Electrochemical Society. Source

Beug M.F.,Physikalisch - Technische Bundesanstalt | Melde T.,Nanoelectronic Material Laboratory GmbH | Paul J.,Fraunhofer Center for Nanoelectronic Technologies | Knoefler R.,Infineon Technologies
IEEE Transactions on Electron Devices

The sidewall gate-etch damage influence on the electrical behavior of 48-nm TaN/Al 2O 3/SiN/SiO 2/Si (TANOS) nand charge-trapping memory cells is investigated in detail. This etch damage occurs at the sidewall of the high work-function TaN metal gate and high-k Al 2O 3 blocking-oxide layers and adversely affects the electrical performance and the mechanical stability of small-ground-rule TANOS cells. Both issues could be solved for 48-nm TANOS cells by the introduction of a new integration scheme, which includes a removable encapsulation liner. This SiN liner protects the TaN sidewall from the etch damage during the aggressive Al 2O 3 high-k etch process. The optimum of the 48-nm electrical cell performance was found for a 4-nm encapsulation liner thickness. In contrast to 48-nm TANOS cells, the encapsulation liner thickness does not affect the electrical performance of large 5-μ m-long-and-wide memory cells. The memory cell performance dependence on the TANOS liner thickness and memory cell size is explained by a damaged Al 2O 3 region approximately 34 nm thick at the block oxide side wall. As a result, the reported etch damage exhibits a new scaling issue for TANOS memory cells around the 20-nm technology node when the total encapsulation liner thickness approaches half of the memory cell length. © 2011 IEEE. Source

Heintze C.,Helmholtz Center Dresden | Hernandez-Mayoral M.,CIEMAT | Ulbricht A.,Helmholtz Center Dresden | Bergner F.,Helmholtz Center Dresden | And 3 more authors.
Journal of Nuclear Materials

Ferritic/martensitic high-chromium steels are leading candidates for fission and fusion reactor components. Oxide dispersion strengthening is an effective way to improve properties related to thermal and irradiation-induced creep and to extend their elevated temperature applications. An extensive experimental study focusing on the microstructural characterization of oxide-dispersion strengthened Fe-9wt%Cr model alloys is reported. Several material variants were produced by means of high-energy milling of elemental powders of Fe, Cr and commercial yttria powders. Consolidation was based on spark plasma sintering. Special emphasis is placed on the characterization of the nano-particles using transmission electron microscopy, small-angle neutron scattering and atom probe tomography. The microstructure of the investigated alloys and the role of the process parameters are discussed. Implications for the reliability of the applied characterization techniques are also highlighted. © 2011 Elsevier B.V. All rights reserved. Source

Gault B.,University of Oxford | Muller M.,University of Oxford | La Fontaine A.,University of Sydney | Moody M.P.,University of Sydney | And 4 more authors.
Journal of Applied Physics

The impact of laser pulsing on the field evaporation process is investigated for Al and W by pulsed laser atom probe tomography. Quantitative analysis reveals the influence on the spatial resolution of the peak temperature reached by the specimen following light absorption from the laser pulse. It is concluded that surface migration processes induce significant degradation of the lateral resolution, changing by 100% and 20%, respectively, for Al and W when the specimen temperature is increased from 4% to 7% of the material's melting point, while the in-depth resolution is shown to remain nearly constant for both materials. © 2010 American Institute of Physics. Source

Gerlich L.,Fraunhofer Center for Nanoelectronic Technologies | Ohsiek S.,Globalfoundries | Klein C.,Globalfoundries | Geiss M.,Globalfoundries | And 3 more authors.
Microelectronic Engineering

As a consequence of device shrinking the resistivity of the widely used TaN/Ta double barrier layer becomes an increasingly important parameter for device speed beyond the 32 nm technology node. In this study we describe the optimization of the deposition of TaN/Ta stacks in such a way that tantalum nitride layer thickness is minimized and tantalum grows in the favorable conducting α-phase. In the first part of the study we used in situ ARXPS to investigate the growth of different tantalum nitride layers on SiO2 and SiOCH as a function of deposition time, nitrogen flow and deposition power. In the second part we analyzed the crystalline phase of a 20 nm thick tantalum layer deposited on top of the same series of tantalum nitride layers characterized in the growth study. The main findings are the appearance of tantalum carbide and tantalum silicide as interface species for the deposition on SiOCH and only tantalum silicide for the deposition on SiO2. We found that α-tantalum grows preferably on tantalum carbide and nitrogen rich intermediate layers whereas silicide at the interface promotes the growth of β-tantalum. To verify these findings we studied two additional modifications of the interface. A lower bias power for a deposition of tantalum nitride on SiO2 was used to confirm the role of tantalum silicide and a thermal treatment of a thin tantalum layer on SiOCH was applied to confirm the role of tantalum carbide. Finally, the contact resistance in via chains on patterned wafers for four selected processes showed the same trends as the sheet resistance of the corresponding barrier films on blanket wafer experiments. © 2013 Elsevier B.V. All rights reserved. Source

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