ICMCTF 2012! - CD-Lab Application Oriented Coating Development

growth; all films are c-axis oriented and have a columnar structure, but the
alloying of AlN with ScN results in a deterioration of the crystalline quality
due to phase instabilities.
Nanoindentation with simultaneous measurement of load and electrical
voltage was used to characterize the nanoscale electromechanical properties
of the piezoelectric films. Testing was done by a TI-950 Hysitron
Triboindenter configured to perform electrical measurements with a
conductive Berkovich boron-doped diamond tip. For all compositions, the
films show a linear relationship of the applied force to the generated
voltage. For loads ranging from 0.1 to 11 mN, output maximum voltages
from 2 to 60 mV were obtained, depending on applied forces and
composition. Consistent values of generated voltages were measured after
multiple force cycles with no hysteresis observed in the results. No
influence of the nanoindentation loading rate on peak voltage generation
was detected. The results were also correlated to data obtained by
piezoresponse force microscopy (PFM).
[1] F. Tasnádi, B. Alling, C. Höglund, G. Wingqvist, J. Birch, L. Hultman,
and I. A. Abrikosov, Phys. Rev. Lett. 104, 137601 (2010).
4:50pm C5-1/F7-1-11 Investigating the degradation behavior under
Hot Carrier Stress for InGaZnO TFT with symmetric and asymmetric
structure, M.Y. Tsai (baxiatwice@yahoo.com.tw), NSYSU, Taiwan
This letter studies the hot-carrier effect in indium–gallium–zinc oxide
(IGZO) thin film transistors with symmetric and asymmetric source/drain
structures. The different degradation behaviors after hot carrier stress in
symmetric and asymmetric source/drain device indicate that different
mechanisms dominate the degradation. Since the C-V measurement is
highly sensitive to the trap state compared with the I-V characteristics, thus,
the C-V curves are utilized to analyze the hot carrier stress induced trap
state generation. Furthermore, the asymmetric C-V measurements (gate-todrain
capacitance, gate-to-source capacitance) are useful to analyze the trap
state location. For asymmetric device structure, different source/drain
structure under hot carrier stress will induce asymmetric electrical field and
cause different degradation behaviors. In this work, the on-current and
subthreshold swing (S.S) degrade under low electrical field, whereas the
apparent Vt shift occurs under large electrical field. The different
degradation behavior indicates that the trap state generates under low
electrical field and channel-hot-electron (CHE) effect occurs under large
electrical field.
Tribology & Mechanical Behavior of Coatings and
Engineered Surfaces
Room: Tiki Pavilion - Session E2-2
Mechanical Properties and Adhesion
Moderator: M.T. Lin, National Chung Hsing University,
Taiwan, W. Clegg, University of Cambridge, UK, R.
Chromik, McGill University, Canada, D. Bahr, Washington
State University, US
1:30pm E2-2-1 Micromechanical testing at up to 700 °C and in
vacuum, S. Korte (sandra.korte@cantab.net), University of Erlangen-
Nürnberg, Germany, L. Shiyu, R. Stearn, W. Clegg, University of
Cambridge, UK
Indentation and, more recently, microcompression are often used to
characterise the mechanical properties of ceramics and hard coatings.
However, although high temperature properties are often of interest, testing
is rarely carried out above room temperature. This is due mainly to the
technical difficulties encountered at elevated temperatures, in particular
thermal drift and oxidation of the sample surface and indenter tip.
In this paper, the adaption of a commercial nanoindenter to allow
experiments in vacuum is shown. Testing at up to 700 ° C has recently been
demonstrated and results from nanoindentation and microcompression
experiments on range of materials from soft metals to hard coatings will be
presented to illustrate the capabilities of the technique and material specific
phenomena observed in different testing geometries.
1:50pm E2-2-2 Characterization of a self assembled monolayer using a
MEMS tribogauge, A. Vijayasai, T. Dallas (tim.dallas@ttu.edu), G.
Sivakumar, C. Anderson, R. Gale, G. Ramachandran, Texas Tech
University, US
A MEMS tribogauge was used for on-chip and in-situ characterization of
nano-tribological phenomena (stiction, friction, and wear). The
measurements were made on the sidewall surfaces on the tribogauge at the
fourth structural polysilicon layer in the device. The device consists of two
Thursday Afternoon, April 26, 2012 90
orthogonally oriented comb-drive mechanisms that are used for both
actuation and sensing functions. One actuator applies a normal load (Fn) to a
contacting surface, while the other actuator induces a tangential load (FT). A
LabVIEW controlled AD7747 capacitance sensor is used to measure the
position of the interacting surfaces. This data is converted into adhesive
force information. The spatial resolution of the characterization apparatus is
±10nm.
Experiments were conducted with tribogauges with and without a selfassembled
monolayer (SAM) coating. The SAM coatings being explored
have either a fluorocarbon tail or a hydrocarbon tail group. The tribogauge
with no SAM coating is UV/Ozone cleaned to remove organic
contaminants, leaving behind –OH bonds on top of the MEMS surface
(native oxide, SiO2). The tribogauge characterization includes:
measurement of baseline stiction force, static and dynamic coefficient of
friction, and induced stiction force calculated after specific load cycles
(Finduced). The UV/Ozone treated tribogauge was used to measure the
baseline stiction force (Fplasma). Additional experiments showed that the
induced stiction force increases in proportion to the increase in the number
of load cycles, indicating erosion of the SAM coating and topographical
changes to the interacting surfaces.
2:10pm E2-2-3 In-situ SEM mechanical testing for adhesion energy
mapping of multilayered Cu wiring structures in integrated circuits, S.
Kamiya (kamiya.shoji@nitech.ac.jp), N. Shishido, H. Sato, K. Koiwa,
Nagoya Institute of Technology, JST CREST, Japan, M. Omiya, Keio
University, JST CREST, Japan, C. Chen, Nagoya Institute of Technology,
Japan, M. Nishida, Nagoya Institute of Technology, JST CREST, Japan, T.
Nakamura, T.S. Suzuki, Fujitsu Laboratories Limited, Japan, T. Nokuo, T.
Nagasawa, JEOL Limited, JST CREST, Japan INVITED
The local distribution of interface strength in a large scale integrated circuit
(LSI) micro structure, which was not uniform nor the same as the average
value obtained with conventional macro scale specimens, was investigated
by applying a recently developed evaluation technique with a sub-micron
range spatial resolution.
Three dimensionally stacked interconnect structures in LSIs frequently
suffer from unexpected fracture, especially at the interfaces, due to stresses
arisen in many steps of fabrication process. In spite of intensive efforts to
avoid such damages, it still threatens the development process to push up
the risk and thus the cost. The most likely reason for this frustrating
situation could be that they are designed essentially on the basis of average
strength data, obtained only from macro-scale specimens with blanket films
of the composing materials by applying conventional techniques such as
four point bending tests. For the case of micro-scale structures, there must
be expected scatters of local strength, leading to weak spots from which
cracks may extend. Therefore establishment of microscopic testing method
was necessary to evaluate local strength distribution of interface, i.e., to
map the strength of structural components with the same range of
resolutions corresponding to the actual structure dimensions in LSI.
A dual beam system with a scanning electron microscope (SEM) and a
focused ion beam (FIB) is further equipped with a nano-indenter for
mechanical loading. In order to evaluate the interface adhesion energy
between Cu damascene lines and cap layers, which is the weakest interface
in such LSI interconnect systems, specimens were fabricated by FIB as
blocks of the insulation layer with the dimensions down to sub-micron
range. Fracture loads obtained by the experiment with the indenter under
SEM observation were compared with the elastic-plastic interface crack
extension simulations to determine the bonding energy, i.e. the the
toughness of interface. Furthermore, not only the toughness but also the
crystallographic orientations of Cu at the points of experiment, which was
expected to be a cause of difference in the strength, was mapped by using
an electron beam back scatter (EBSD) analyzer installed in the system. The
correlation among the toughness, crystallographic structure and
configuration of interconnects was investigated in detail on the basis of
those distribution maps with a sub-micron resolution, aiming at establishing
a possible design scheme to avoid unexpected fracture during the
fabrication process of LSI.
2:50pm E2-2-5 Preparation and Characterization of Super- and
Ultrahard Nanocomposites, S. Veprek (stan.veprek@lrz.tum.de), M.
Veprek-Heijman, Technical University Munich, Germany, A.S. Argon,
Massachusetts Institute of Technology, US
In the first part of our presentation, we shall identify several serious
inconsistencies and methodological mistakes in the presentation of Fischer-
Cripps as far as we can identify them presently from the press release on his
home page and from a manuscript available to us [1]. We shall further show
that the hardness of the nc-TiN/a-Si3N4/TiSi2 of about 80 to 100 GPa
reported in our earlier papers (see [2] for a review) is supported by our
indentation measurements as well as by scanning electron micrographs of
the remaining indentations. We shall further briefly outline the issue of the