ISSN 10637397, Russian Microelectronics, 2015, Vol. 44, No. 6, pp. 410–413. © Pleiades Publishing, Ltd., 2015.
Original Russian Text © O.S. Trushin, A.N. Kupryanov, S.C. Ying, E. Granato, T. AlaNissila, 2015, published in Mikroelektronika, 2015, Vol. 44, No. 6, pp. 459–463.
Heteroepitaxial systems play an important role in
modern microelectronic technology. Multilayered
magnetoresistive structures are basic ingredients for
magnetic field sensors, and widely used for reading
information from computer hard discs. An important
example is the heteroepitaxial system Cu/Ni(001).
Due to lattice mismatch between the film and the sub
strate (the relative mismatch is
= 2.6%), consider
able elastic strain is accumulated during thin film
growth. This strain is relaxed above the critical thick
ness of the film through defect nucleation.
However, the geometry of atomic packing in an
FCC lattice with (001) surface orientation sets certain
restrictions on the types of defects which are possible
in this system. The surface of the crystal in this case
has a square symmetry that complicates processes of
edge dislocation nucleation in this geometry.
Experimental studies of the Cu/Ni(001) system
have revealed formation of defects of unusual shapes
(in particular the
shaped defect which has been
called “internal (111) faceting”) for film thicknesses
less than 20 ML . The growth of Cu thin films on
Ni(001) substrate has been studied using STM micros
copy in Ref. 1. The authors suggested their own geo
metrical model of the defect. According to their
assumption, a wedge shaped part of the Cu film is mov
ing at the bridge position creating an extended defect.
This kind of defect is characterized by the presence of a
surface step, with an average height of about
The article was translated by the authors.
A similar heteroepitaxial system has been studied
recently using surface Xray diffraction, and the exist
ence of a new type of defect suggested in Ref. 1 was
supported . Molecular Dynamics (MD) simula
tions of this system have found the formation of a rect
angular network of dislocations at Cu film thicknesses
above 4 ML . However, to our knowledge, system
atic studies of the nature of the
type defect and its
energetics have not yet been done. This might be due
to the fact that in atomistic simulations very large sys
tem sizes should be used for correct modeling of long
range elastic strain fields around the defect region.
The aim of the present work is to perform system
atic numerical studies of defect nucleation in the het
eroepitaxial Cu/Ni(001) system using molecular static
methods and semiempirical Embedded Atom
Method (EAM) potentials.
To shed more light on the nature and energetics of
possible defects in Cu/Ni(001), we have performed
systematic studies of this structure through computer
simulations using molecular static methods. Many
body atomic potentials of the EAM type  were used
for modeling the interatomic forces in the system. The
computational model system has the shape of a paral
lelepiped, consisting of 30 atomic layers of Ni (repre
senting the substrate), and varying number of Cu lay
ers (1–20) (representing the film). Crystal orientation
of the substrate surface was (001). Edges of the com
putational domain, namely OX, OY, OZ were oriented
, directions, respectively.
Atomic Mechanisms of Strain Relaxation
in Heteroepitaxial Cu/Ni(001) System
O. S. Trushin
, A. N. Kupryanov
, S.C. Ying
, E. Granato
, and T. AlaNissila
Institute of Physics and Technology, Yaroslavl Branch, Academy of Sciences of Russia, Yaroslavl 150007, Russia
Department of Physics, P.O. Box 1843, Brown University, Providence, Rhode Island 029121843, USA
Laboratório Associado de Sensores e Materiais, Instituto Nacional de Pesquisas Espaciais,
12227010 São José dos Campos, SP, Brazil
COMP CoE at the Department of Applied Physics, Aalto University School of Science,
P.O. Box 10000, FIN00076 Aalto, Espoo, Finland
Received December 29, 2014
—Strain relief mechanisms in heteroepitaxial Cu/Ni(001) system are studied using molecular static
methods with semiempirical EAM potentials. In particular, the process of a
shape defect (internal (111)
faceting) nucleation is considered, and the corresponding activation barriers and critical thicknesses are esti