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Suche nach „[M.] [Lanza]“ hat 15 Publikationen gefunden
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    NachhaltigElektrotechnik und MedientechnikIQMA

    Zeitschriftenartikel

    Christoph Metzke, Werner Frammelsberger, Jonas Weber, F. Kühnel, K. Zhu, M. Lanza, Günther Benstetter

    On the Limits of Scanning Thermal Microscopy of Ultrathin Films

    Materials, vol. 13, no. 3

    2020

    DOI: 10.3390/ma13030518

    Abstract anzeigen

    Heat transfer processes in micro- and nanoscale devices have become more and more important during the last decades. Scanning thermal microscopy (SThM) is an atomic force microscopy (AFM) based method for analyzing local thermal conductivities of layers with thicknesses in the range of several nm to µm. In this work, we investigate ultrathin films of hexagonal boron nitride (h-BN), copper iodide in zincblende structure (γ-CuI) and some test sample structures fabricated of silicon (Si) and silicon dioxide (SiO2) using SThM. Specifically, we analyze and discuss the influence of the sample topography, the touching angle between probe tip and sample, and the probe tip temperature on the acquired results. In essence, our findings indicate that SThM measurements include artefacts that are not associated with the thermal properties of the film under investigation. We discuss possible ways of influence, as well as the magnitudes involved. Furthermore, we suggest necessary measuring conditions that make qualitative SThM measurements of ultrathin films of h-BN with thicknesses at or below 23 nm possible.

    NachhaltigElektrotechnik und MedientechnikIQMA

    Zeitschriftenartikel

    C. Wen, X. Jing, F. Hitzel, C. Pan, Günther Benstetter, M. Lanza

    In Situ Observation of Current Generation in ZnO Nanowire Based Nanogenerators Using a CAFM Integrated into an SEM

    ACS Applied Materials & Interfaces, vol. 11, no. 17, pp. 15183-15188

    2019

    DOI: 10.1021/acsami.9b00447

    Abstract anzeigen

    In this work, we monitor in situ the movement of ZnO piezoelectric nanowires by using a conductive atomic force microscope integrated into a scanning electron microscope. This setup allows seeing the bending of the nanowires and simultaneously measuring the currents generated. We conclude that the currents generated not only come from piezoelectric effect, but also from contact potential and triboelectric effect. These contributions have been ignored in all previous reports in this field, meaning that the power conversion efficiency of these devices may have been systematically overestimated. Our study helps to clarify the working mechanism of piezoelectric nanogenerators based on ZnO nanowires.

    NachhaltigElektrotechnik und MedientechnikIQMAMaschinenbau und Mechatronik

    Zeitschriftenartikel

    L. Jiang, Jonas Weber, F. Puglisi, P. Pavan, L. Larcher, Werner Frammelsberger, Günther Benstetter, M. Lanza

    Understanding Current Instabilities in Conductive Atomic Force Microscopy

    Materials, vol. 12, no. 3

    2019

    DOI: 10.3390/ma12030459

    Abstract anzeigen

    Conductive atomic force microscopy (CAFM) is one of the most powerful techniques in studying the electrical properties of various materials at the nanoscale. However, understanding current fluctuations within one study (due to degradation of the probe tips) and from one study to another (due to the use of probe tips with different characteristics), are still two major problems that may drive CAFM researchers to extract wrong conclusions. In this manuscript, these two issues are statistically analyzed by collecting experimental CAFM data and processing them using two different computational models. Our study indicates that: (i) before their complete degradation, CAFM tips show a stable state with degraded conductance, which is difficult to detect and it requires CAFM tip conductivity characterization before and after the CAFM experiments; and (ii) CAFM tips with low spring constants may unavoidably lead to the presence of a ~1.2 nm thick water film at the tip/sample junction, even if the maximum contact force allowed by the setup is applied. These two phenomena can easily drive CAFM users to overestimate the properties of the samples under test (e.g., oxide thickness). Our study can help researchers to better understand the current shifts that were observed during their CAFM experiments, as well as which probe tip to use and how it degrades. Ultimately, this work may contribute to enhancing the reliability of CAFM investigations.

    NachhaltigElektrotechnik und MedientechnikIQMA

    Zeitschriftenartikel

    S. Chen, L. Jiang, M. Buckwell, X. Jing, Y. Ji, E. Grustan-Gutierrez, Günther Benstetter, F. Hui, Y. Shi, M. Rommel, A. Paskaleva, W. Ng, A. Mehonic, A. Kenyon, M. Lanza

    On the Limits of Scalpel AFM for the 3D Electrical Characterization of Nanomaterials

    Advanced Functional Materials, vol. 28, no. 52

    2018

    DOI: 10.1002/adfm.201802266

    Abstract anzeigen

    Conductive atomic force microscopy (CAFM) has been widely used for electrical characterization of thin dielectrics by applying a gentle contact force that ensures a good electrical contact without inducing additional high‐pressure related phenomena (e.g., flexoelectricity, local heat, scratching). Recently, the CAFM has been used to obtain 3D electrical images of thin dielectrics by etching their surface. However, the effect of the high contact forces/pressures applied during the etching on the electrical properties of the materials has never been considered. By collecting cross‐sectional transmission electron microscopy images at the etched regions, it is shown here that the etching process can modify the morphology of Al2O3 thin films (producing phase change, generation of defects, and metal penetration). It is also observed that this technique severely modifies the electrical properties of pSi and TiO2 wafers during the etching, and several behaviors ignored in previous studies, including i) observation of high currents in the absence of bias, ii) instabilities of etching rate, and iii) degradation of CAFM tips, are reported. Overall, this work should contribute to understand better the limitations of this technique and disseminate it among those applications in which it can be really useful.

    NachhaltigElektrotechnik und MedientechnikIQMAMaschinenbau und Mechatronik

    Beitrag (Sammelband oder Tagungsband)

    Günther Benstetter, Alexander Hofer, D. Liu, Werner Frammelsberger, M. Lanza

    Chapter 3: Fundamentals of CAFM Operation Modes

    Conductive Atomic Force Microscopy: Applications in Nanomaterials, Weinheim

    2017

    ISBN: 978-3-527-34091-0

    NachhaltigElektrotechnik und MedientechnikIQMA

    Zeitschriftenartikel

    X. Jing, Emanuel Panholzer, X. Song, E. Grustan-Gutierrez, F. Hui, Y. Shi, Günther Benstetter, Y. Illarionov, T. Grasser, M. Lanza

    Fabrication of scalable and ultra low power photodetectors with high light/dark current ratios using polycrystalline monolayer MoS2 sheets

    Nano Energy, vol. 30, no. December, pp. 494-502

    2016

    NachhaltigElektrotechnik und MedientechnikIQMA

    Zeitschriftenartikel

    Y. Ji, H. Fei, Y. Shi, V. Igelsias, D. Lewis, N. Jiebin, S. Long, M. Liu, Alexander Hofer, Werner Frammelsberger, Günther Benstetter, A. Scheuermann, P. McIntyre, M. Lanza

    Characterization of the photocurrents generated by the laser of atomic force microscopes

    Review of Scientific Instruments, vol. 87, no. 8

    2016

    DOI: 10.1063/1.4960597

    Abstract anzeigen

    The conductive atomic force microscope (CAFM) has become an essential tool for the nanoscale electronic characterization of many materials and devices. When studying photoactive samples, the laser used by the CAFM to detect the deflection of the cantilever can generate photocurrents that perturb the current signals collected, leading to unreliable characterization. In metal-coated semiconductor samples, this problem is further aggravated, and large currents above the nanometer range can be observed even without the application of any bias. Here we present the first characterization of the photocurrents introduced by the laser of the CAFM, and we quantify the amount of light arriving to the surface of the sample. The mechanisms for current collection when placing the CAFM tip on metal-coated photoactive samples are also analyzed in-depth. Finally, we successfully avoided the laser-induced perturbations using a two pass technique: the first scan collects the topography (laser ON) and the second collects the current (laser OFF). We also demonstrate that CAFMs without a laser (using a tuning fork for detecting the deflection of the tip) do not have this problem.

    Elektrotechnik und MedientechnikIQMA

    Zeitschriftenartikel

    V. Iglesias, M. Lanza, K. Zhang, A. Bayerl, M. Porti, M. Nafría, X. Aymerich, Günther Benstetter, Z. Shen, G. Bersuker

    Degradation of polycrystalline HfO2 based gate dielectrics under nanoscale electrical stress

    Applied Physics Letters, vol. 99

    2011

    Abstract anzeigen

    The evolution of the electrical properties of HfO2/SiO2/Si dielectric stacks under electrical stress has been investigated using atomic force microscope-based techniques. The current through the grain boundaries (GBs), which is found to be higher than thorough the grains, is correlated to a higher density of positively charged defects at the GBs. Electrical stress produces different degradation kinetics in the grains and GBs, with a much shorter time to breakdown in the latter, indicating that GBs facilitate dielectric breakdown in high-k gate stacks.

    Elektrotechnik und MedientechnikIQMA

    Zeitschriftenartikel

    A. Bayerl, M. Lanza, M. Porti, M. Nafría, X. Aymerich, F. Campabadal, Günther Benstetter

    Nanoscale and Device Level Gate Conduction Variability of High-k Dielectrics-Based Metal-Oxide-Semiconductor Structures

    IEEE Transactions on Device and Materials Reliability, vol. 11, no. September, pp. 495-501

    2011

    DOI: 10.1109/TDMR.2011.2161087

    Abstract anzeigen

    The polycrystalline microstructure of the high-k dielectric of gate stacks in metal-oxide-semiconductor (MOS) devices can be a potential source of variability. In this paper, a conductive atomic force microscope (CAFM) and a Kelvin probe force microscope (KPFM) have been used to investigate how the thickness and the crystallization (after a thermal annealing) of the high-k layer affect the nanoscale morphological and electrical properties of the gate stack. The impact of such nanoscale properties on the reliability and variability of the global gate electrical characteristics of fully processed MOS devices has also been investigated.

    Elektrotechnik und MedientechnikIQMA

    Zeitschriftenartikel

    A. Bayerl, M. Lanza, M. Porti, F. Campabadal, M. Nafría, X. Aymerich, Günther Benstetter

    Reliability and gate conduction variability of HfO2-based MOS devices: A combined nanoscale and device level study

    Microelectronic Engineering, vol. 88, pp. 1334-1337

    2011

    Abstract anzeigen

    The electrical properties and reliability of MOS devices based on high-k dielectrics can be affected when the gate stack is subjected to an annealing process, which can lead to the polycrystallization of the high-k layer. In this work, a Conductive Atomic Force Microscope (C-AFM) has been used to study the nanoscale electrical conduction and reliability of amorphous and polycrystalline HfO2 based gate stacks. The link between the nanoscale properties and the reliability and gate conduction variability of fully processed MOS devices has also been investigated.

    Elektrotechnik und MedientechnikIQMA

    Zeitschriftenartikel

    M. Lanza, M. Porti, M. Nafría, X. Aymerich, Günther Benstetter, Edgar Lodermeier, Heiko Ranzinger, G. Jaschke, S. Teichert, L. Wilde, P. Michalowski

    Conductivity and Charge Trapping After Electrical Stress in Amorphous and Polycrystalline Al2O3-Based Devices Studied With AFM-Related Techniques

    IEEE Transactions on Nanotechnology, vol. 10, no. 2, pp. 344-351

    2011

    Abstract anzeigen

    In this paper, atomic force microscopy-based techniques have been used to study, at nanoscale, the dependence of the electrical properties of Al2O3 stacks for flash memories on the annealing temperature (T-A). The electrical characterization has been combined with other techniques (for example, transmission electron microscopy) that have allowed to investigate the dependence of the stack crystallization and the Si diffusion from the substrate to the gate oxide on T-A. The combination of both the analyses has allowed to explore if there is a relation between the percentage of diffused silicon and material crystallization with the conductivity and charge trapping of Al2O3 stacks.

    Elektrotechnik und MedientechnikIQMA

    Zeitschriftenartikel

    M. Lanza, M. Porti, M. Nafría, X. Aymerich, Günther Benstetter, Edgar Lodermeier, Heiko Ranzinger, G. Jaschke, S. Teichert, L. Wilde, P. Michalowski

    Crystallization and silicon diffusion nanoscale effects on the electrical properties of Al2O3 based devices

    Microelectronic Engineering, vol. 86, no. 7-9, pp. 1921-1924

    2009

    Abstract anzeigen

    In this work, Atomic Force Microscopy (AFM) based techniques are used to study, at the nanoscale, the dependence of the electrical properties of Al2O3 stacks for Flash memories on the percent of diffused Silicon and material crystallization after being annealed at different temperatures.

    Elektrotechnik und MedientechnikIQMA

    Vortrag

    M. Lanza, M. Porti, M. Nafría, X. Aymerich, Günther Benstetter, et al.

    Crystallization and Silicon Diffusion Nanoscale Effects on the Electrical Properties of Al2O3 Based Devices

    Conference of Insulating Films on semiconductors (INFOS 2009), Cambridge, Großbritannien

    2009

    Elektrotechnik und MedientechnikIQMAMaschinenbau und Mechatronik

    Vortrag

    M. Lanza, M. Porti, M. Nafría, Günther Benstetter, Werner Frammelsberger, Heiko Ranzinger, Edgar Lodermeier, G. Jaschke

    Influence of the manufacturing process on the electrical properties of thin (< 4 nm) Hafnium based high-k stacks observed with CAFM

    18th European Symposium on Reliability of Electronic Devices, Failure Physics and Analysis (ESREF), Arcachon, Frankreich

    2007

    Elektrotechnik und MedientechnikIQMAMaschinenbau und Mechatronik

    Zeitschriftenartikel

    M. Lanza, M. Porti, M. Nafría, Günther Benstetter, Werner Frammelsberger, Heiko Ranzinger, Edgar Lodermeier, G. Jaschke

    Influence of the manufacturing process on the electrical properties of thin (< 4 nm) Hafnium based high-k stacks observed with CAFM

    Microelectronics Reliability, vol. 47, no. 9, pp. 1424-1428

    2007

    Abstract anzeigen

    In this work, the dependence of the electrical characteristics of some thin (<4 nm) HfO2, HfSiO and HfO2/SiO2 stacks on their manufacturing process is studied at the nanoscale. Topography, current maps and current–voltage (I–V) characteristics have been collected by conductive atomic force microscope (CAFM), which show that their conductivity depends on some manufacturing parameters. Increasing the annealing temperature, physical thickness or Hafnium content makes the structure less conductive.