Study of SiO
2
/Si Interface by Surface Techniques

39
Arbitary units
Binding Energy, eV
158 152
0
0.5
1
1.5
2
2.5
3
3.5
4
4.5
5
Arbitary units
Binding Energy, eV
108 100
0
0.5
1
1.5
2
2.5
3
3.5

rather constant thickness (about 2.5±0.5 nm) running along the surface.
In the thinner areas of the specimen (Fig. 16 ( b)), the assembling resin has been removed by
ion milling while a band of amorphous material with the same thickness (2.5±0.5 nm)
running parallel to the crystalline surface is still observable.
We conclude, therefore, that the thickness of the amorphous Si layer on top of the Si(001)
wafer measured by TEM is 2.5±0.5 nm.

Crystalline Silicon – Properties and Uses

40

(a)

(b)
Fig. 16. (a) Cross-section TEM image of the Si surface in a thicker area of the specimen where
the assembling resin is still visible after the ion milling. Inset shows the (b) Cross-section
TEM image of the Si surface in a thinner of the specimen, where the assembling resin has
been removed by ion milling.
As it was stated in previous works [29, 30, 31] the interface between crystalline Si and its
amorphous native oxide SiO
2
is the basis for most current computer technology, although its
structure is poorly understood. In this line, the study of the structural properties of water
near a silica interface by classical and ab-initio molecular dynamics simulations is a part of
this effort. The orientation of water molecules at the interface determined in classical force
fields and quantum simulations [30] show that near the interface the water molecules are
oriented such that at least one of the hydrogen atoms are nearer the silica than the oxygen of
the water molecule. The importance of characterizing the atomic structure of the

Study of SiO

Si (001) wafer measured by TEM is 2.5±0.5 nm.
6. References
[1] F. J. Himpsel, F.R.Mc Feely, A.Taleb-Ibrahimi and J.A.Yarmoff, Physical Review B, Vol.38,
No.9, pp.6084-6095 (1988)
[2] M. Razeghi Technology of Quantum Devices pp.42 LLC (2010), Springer, ISBN 978-1-4419-
1055-4
[3] F. Yano, A.Hiroaka, T.Itoga, H.Kojima and K.Kanehori ,J.Vac. Sci.Technol A, Vol.13, No.6
pp.2671 (1995)
[4] G. W. Rubloff, J.Vac.Sci.Technol. A, Vol.8, No.3, pp.1857 (1990)
[5] T. Hattori and T.Suzuki, Appl.Phys.Lett, Vol.43, No.5 pp.470 (1983)
[6] R. Haight and L.C.Feldman, J.Appl.Phys, Vol.53, pp.4884 (1982)
[7] F.J.Grunthaner, P.J. Grunthaner, R.P.Vasquez , B.F.Lewis and J.Maserjian,
J.Vac.Sci.Technol 16 pp.1443 (1979)
[8] A. Kalnitshi, S.P.Tay, J.P.Ellul, S.Chongsawangvirod, J.W.Andrews and E.A Irene
J.Electrochem. Soc. 137, pp.235 (1990)
[9] Z. H. Lu, J.P.Mc Caffrey, B.Brar, G.D.Wilk, R.M. Wallace, L.C.Feldman and S.P. Tay,
Appl.Phys Lett. Vol.71 No.19, pp.2764 (1997)
[10] R. Held, T.Vancura, T.Heinzel, K.Ensslin, M.Holland, W.Wegscheider,
Appl.Phys.Lett,Vol.73, No.2 pp.262 (1998)
[11] The physics of SiO
2
and its Interfaces

edited by Sokrates T.Pantelides (Pergamon, New
York, 1978)
[12] F. J. Grunthaner and P.J.Grunthaner, Mater, Sci Rep. 1, pp.65 (1986)
[13] Proceedings of the 173-rd meeting of the Electrochemical Society, Atlanta, Georgia, 1988,
edited by C.R.Helms
[14] F. Rochet, S.Rigo, M.frament, C.D’Anterroches, C.Maillot, H.Roulet and G.Dufour,
Adv.Phys. 35, pp.237 (1986)

Electric Field-induced Characteristics
of Device-Quality Silicon at Room Temperature
Khlyap Halyna, Laptev Viktor, Pankiv Lyudmila and Tsmots Volodymyr
1
State Pedagogical University, Drohobych
2
Russian New University, Moscow
1
Ukraine
2
Russian Federation
1. Introduction

There is no needing emphasize about the importance of silicon (Si) as a material of choice for
almost all fields of the new nano- and microelectronics. Due to its unique structural and
physical properties, polycrystalline Si seems to be of special interest as a base for creating
so-called 3D-integrated circuits.
Various studies have established the main processes of carrier transport in the structures
based on this material. In particular, it was shown that tunneling and diffusion
recombination processes dominate under room temperature and applied low electric fields.
Nevertheless, the analysis and numerical simulation of the experimental data do not always
take into account the finite dimensions of the investigated structure and the appearance of
carrier depletion as an important component of the tunneling current observed
experimentally. Besides that, the fabrication of any device based on polycrystalline Si
requires high-temperature treatment. Therefore, the effect of such a treatment on the electric
properties of polycrystalline, amorphous and monocrystalline Si is also seemed to be
important. Regardless of the huge number of publications describing numerous
characteristics of the material and structures based on polycrystalline Si of various types of
conductivity, the question about room temperature carrier depletion (exclusion from the
contact regions) in polycrystalline material is still open.

object of the room temperature investigations. Amorphous silicon thin films (thickness up to
300 nm) were manufactured by magnetron sputtering technology in the range of the current
density (10
-9
-10
-7
) A/cm
2
at T = 300 K.
Current-voltage characteristics nd photosensitivity of the samples was carried out under
normal atmospheric conditions before and after the treatment of the structures in molecular
hydrogen. The hydrogenation of the samples was provided by the special chamber filled
in with molecular H2 during 24 hours at T = 400
0
C and the gas pressure P
H
= 2500 Pa
(Khlyap, 2003). Fig. 1. Sketch of the experimental sample.

The experimental setup is plotted in Fig. 1. -Si layers of 1 μm thickness were deposited on
the glass substrate by magnetron sputtering under activation of SiH
4
(silane) plasma
dissociation at alternate pulse bias with 55 Hz frequency. Pressure and temperature in the
growth chamber were P = 70 Pa and 225
0
C, respectively. Aluminum (Al) contacts doped

/k
B
T)
m
, (2)
where I
s
is a saturation current defined by the parameters of the film (charge carrier mobility
and the dangling bonds density as well as by the tunneling transparency coefficient of the
Al - -Si barrier (Terukov, 2000&2001).
Fig. 2. Current-voltage characteristic of the investigated sample (T = 300 K) (Khlyap, 2003).
Fig. 3. Current-voltage characteristics of the investigated structure in double-log scale
(Khlyap, 2003).
Re-building the experimental IVC in double-log scale (Fig. 3) allows obtaining more detail
information about current mechanisms in the structures investigated.

0 20406080100
1E-10
1E-9
1E-84
2
3
1
Current I, A
Applied voltage V
a
, V

Appearance of these centers causes the space charge limited current (SCLC). Fig. 4. Schematic drawing of the energy levels in the forbidden gap of amorphous silicon
under thermodynamic equilibrium. E
t
is the trap level, F
0
is the Fermi level position
(Terukov, 2000&2001).
In absence of the external electric field the initial electron concentration in the investigated
films is low and determined by the localization of the Fermi level of the material. In turn, the
Fermi level localization depends on the concentration and the ionization energy of the trap
centers E
t
. Under small applied bias the electrons injected from the Al contacts are confined
by the traps E
t
. As the applied voltage increases, the centers E
t
receive more and more
electrons; at the same time, the concentration of the injected charge carriers is also
increasing. This process is experimentally observed in the linear sections of the IVCs with
different slopes m. UV-radiation accelerates the interaction between the injected charge
carriers and the ones accumulated by the trap centers [Terukov, 2000; Khlyap, 2003).

The IR-photosensitivity of the films is of particular importance. The challenge is that the as-
grown films are quite not photosensitive. One of the simplest ways to make the layers
photosensitive is hydrogenation treatment of the films under certain temperatures. The as-
grown layers were placed in the special chamber filled with the molecular hydrogen for 24

3
COOH = 3:1:1 and rinsed in unionized water in order
to maximally avoid the possible influence of surface effects on the results of electrical
measurements. The studies were carried out at room temperature under applied electric
fields 0 – 104 Vm
-1
, corresponding to applied biases in the range of 0 – 190 V.
Fig. 5. Experimental current-voltage characteristics of the investigated samples after
hydrogenation (Khlyap, 2003).
High-temperature (up to 1200
0
C) heat treatment of the samples was performed under
normal atmospheric conditions during 6 h in the furnace of the special construction
providing a stationary temperature gradient along the sample. The measurements of
current-voltage characteristics (IVC) were performed by means of the traditional bridge
method (Sze). Indium contacts were thermally deposited on the lateral facets of the sample.
The left and right contacts will be referred further as the first and the second ones,
respectively. All experimental dependencies are represented in the coordinates of ln j ~
(V
a
)
1/2
, where j is the current density and V
a
stands for the applied voltage. Fig. 6 shows the
IVC of the sample of the columnar polycrystalline-like structure. As one can see, both curves
(“forward” and “reverse”) have no considerable difference, indicating a good quality of
metallic contacts. This IVC demonstrates the domination of at least two-step tunneling with
the threshold voltage V
TR

2 - 1500 nm light source
T
exper
= 290 K
24 h H
2
heating, 400
0
C, P = 2500 Pa

Crystalline Silicon – Properties and Uses

48

Fig. 6. Forward (curve 1) and reverse (curve 2) currents of the sample with the columnar
structure before high temperature treatment (Khlyap, 2004). Fig. 7. Current-voltage characteristics of the sample with granular structure before high-
temperature treatment (Khlyap, 2004). Fig. 8. Current-voltage characteristics of both samples (curve1 corresponds to the sample
with granular structure and curve 2 corresponds to the sample with columnar structure)
after high-temperature (900
0
C) treatment (Khlyap, 2004).
Effect of Native Oxide on the Electric Field-induced
Characteristics of Device-Quality Silicon at Room Temperature


)], (3)
where l is the length of the sample, j is the charge carriers flow, L = [(2D
n
D
p
/(D
n
+ D
p
)]
1/2
,
D
n,p
are the diffusion coefficients for electrons and holes and  = 10
-8
s is the lifetime of the
carriers (this value is accepted to be the same for both electrons and holes), n
0
= 10
10
cm
-3

stands for the intrinsic electron concentration, and n
i
= 10
18
cm
-3

)
5/4
[n
i
(a
B
)
3
]
-1/2
, (4)

Crystalline Silicon – Properties and Uses

50
where U
0
is the height of the barrier, E
B
= me
4
/(h
2
/2

2
)
2
and a
B

optimal for i) reduction of the barrier height in samples of granular structure and ii) a
considerable accumulation of carriers in the region of the second contact. The first
experimental results reported in (Khlyap, 2004) demonstrated the possibility of additional
accumulation of charge carriers in bulk polycrystalline Si of n-type conductivity after high
temperature treatment without sufficient increase of the applied electric field (Khlyap, 2004).

4. Electric characteristics of the structure bulk silicon – native oxide
As we have mentioned above, the native oxide formed immediately after the sample
preparation (a bulk specimen or a thin film) is an unavoidable factor of any technological
process and the following design of the active element. We have investigated room-
temperature electrical (current-voltage, IVC, and capacitance-voltage, CVC) characteristics
of the structure bulk silicon-native oxide. The scheme of the contacts (idium pads) deposited
on the bulk silicon sample is illustrated in Fig. 10. Fig. 10. Schematic image of In-contact pads deposited on the bulk crystalline silicon sample
for the room-temperature electric investigations.
We have focused on examining the current-voltage functions registered under the
application of external electric field in directions ‘1-2” and “2-1” as well as in directions “1-3,
2-3” and “3-1, 3-2”. The sets of the device-quality crystalline silicon of n-type conductivity
were chosen for this experiment. The samples were cut off from the as-grown ingots.

The experimental electric field-induced characteristics are plotted in Fig.11, a-c. Obvious
that all the experimental current-voltage functions are described by the power law I~(F
a
)
m
,
where F
a

metal-semiconductor structures. To confirm this conclusion we have made the capacitance-
voltage measurements at T = 290 k and the test signal frequency f = 1 kHz. The experimental
results are plotted in Fig.12, a-c. a)

b)

c)
Fig. 12. Room-temperature capacitance-voltage characteristics of the investigated structure
under the test signal frequency f = 1 kHz: a) contacts 1-2; b) contacts 1-3 (see notes in Fig.10);
c) a control metal-semiconductor structure (In-mono-n-Si).
Effect of Native Oxide on the Electric Field-induced
Characteristics of Device-Quality Silicon at Room Temperature 53
The experimental data have allowed calculating some main parameters of the structure bulk
crystalline silicon-native oxide according to the theory (Sze). The results are listed in Table 1.Charge
centers
concentration
Contact
Space
charge region
width
Diffusion

13
cm
-2
N
02
=1.9410
13
cm
-2

2-3
W
01
=15.5 m
W
02
=15.5 m
V
d1
= 3.50 V,
V
d2
= 4.20 V
Table 1. Electric parameters of the investigated structure.
5. Electric parameters of the structure recrystallized nanocrystalline silicon-
Cu/Ag-nanocluster contacts
The unique room-temperature electrical characteristics of the porous metallic nanocluster-
based structures deposited by the wet chemical technology on conventional silicon-based
solar cells were described in (Laptev & Khlyap, 2008). We have analyzed the current-
voltage characteristics of Cu-Ag-metallic nanocluster contact stripes and we have

a
,
and the reverse current is
I = T
tun
A
el
(2v
s
/L
2
)V
a

(velocity saturation mode). Here T
tun
is a tunneling transparency coefficient of the
potential barrier formed by the ultrathin native oxide films, A
el
and L are the electrical
area and the length of the investigated structure, respectively,  is the electrical
permittivity of the structure, m* is the effective mass of the charge carriers in the metallic
Cu-Ag-nanoclucter structure, and v
s
is the carrier velocity (Kozar et al., 2010). These
experimental data lead to the conclusion that the charge carriers can be ejected from the
pores of the Cu-Ag-nanocluster wire in the potential barrier and drift under applied
electric field (Sze & Ng, 2007; Peleshchak & Yatsyshyn, 1996; Datta, 2006; Ferry &
Goodnick, 2005; Rhoderick, 1978).


7. References
Akopian A.A. et al. (1987), Charge Carrier Exclusion in Ge-Diodes, Semiconductors (Russia),
Vol. 21, p. 1783.
Datta S. (2006). Quantum transport: Atom to Transistor, Cambridge Univ. Press, ISBN 0-521-
63145-9, Cambridge, Great Britain.
Ferry D. & Goodnick S. (2005). Transport in Nanostructures, Cambridge Univ. Press, ISBN 0-
521-66365-2, Cambridge, Great Britain
Khlyap H. et al. (2003), Photosensitive Amorphous Si Thin Films Prepared by Magnetron
Technology, Proceedings of the Materials Research Society, Fall 2002, Boston, USA, Vol.
744, paper No. M5.20.1.
Khlyap H. et al. (2004), Depletion of charge carriers in electronic polycrystalline silicon,
Mater Science in Semicond Processing, Vol. 7, p. 443-446.
Kozar T. V., Karapuzova N. A. & Laptev G. V., Laptev V. I., Khlyap G. M., Demicheva O. V.,
Tomishko A. G., Alekseev A. M. (2010). Silicon Solar Cells: Electrical Properties of
Copper Nanoclusters Positioned in Micropores of Silver Stripe-Geometry Elements,
Nanotechnologies in Russia, Vol. 5, № 7-8,
p.549-553, DOI: 10.1134/S1995078010070165, ISSN: 1995-0780 (print), ISSN: 1995-
0799 (online).
Laptev V.I. & Khlyap H. (2008). High-Effective Solar Energy Conversion: Thermodynamics,
Crystallography and Clusters, In: Solar Cell Research Progress, Carson J.A. (Ed.), pp.
181–204, Nova Sci. Publ., ISBN 978-1-60456-030-5, New York, USA.
Martin I. et al. (2004), Improvement of Crystalline Silicon Surface Pasivation by Hydrogen
Plasma Treatment, Appl. Phys. Lett., Vol. 85, p. 1474-1476.
Peleshchak R.M. & Yatsyshyn V.P. (1996). About effect of inhomogeneous deformation on
electron work function of metals, Physics of Metals and Metallography, MAIK Nauka
Publishers – Springer, vol. 82, No. 3, pp.18-26, ISSN Print: 0031-918X, ISSN Online:
1555-6190.
Reich M. et al. (1988), Effect of Barrier Localizd States on Fluctuations of tunneling
Current Through Metal-semicondutor Contact, Semiconductors (Russia), Vol. 22, p.
1979.

IHP microelectronics, Frankfurt (Oder)
Germany
1. Introduction
Defects in crystalline materials modify locally the periodic order in a crystal structure. They
characterize the real structure and modify numerous physical and mechanical properties of
a crystal. Crystal defects are generally divided by their dimension: point defects are also
known as zero-dimensional (0-D) defects, while dislocations are 1-D, twins and grain
boundaries are 2-D, and precipitates are denoted as 3-D defects. Dislocations were
implemented for the first time in the early 1900th to explain the elastic behavior of
homogeneous, isotropic media. Based on Volterra´s “distorsioni” (Volterra, 1907), Love has
introduced the term “dislocation” to describe a discontinuity of displacement in an elastic
body (Love, 1927). The application of this term to denote a particular elementary type of
deviation from the ideal crystal lattice structure was due to Orowan (1934), Polanyi (1934),
and Taylor (1934a, 1934b).
A dislocation is characterized by a vector parallel to the dislocation line and a displacement
or Burgers vector which is a certain finite increment  induced by the elastic displacement
vector . The Burgers vector is equal to one of the lattice vectors in magnitude and direction
and may be written as (Hirth & Lothe, 1982)

∮


=




=−

. (1)

This phenomenon anticipates the dissociation of a dislocation. The model also explains
the motion of dislocations and results in the introduction of the Peierls energy, which
represents the periodic displacement potential energy, as well as the Peierls stress
required to overcome this potential barrier. The concept of kinks and jogs in dislocation
lines is also a consequence of the model (Friedel, 1979). The Peierls-Nabarro model has
been influential in the development of dislocation theory of more than 60 years. It was, for
instance, modified to explain the dislocation motion (Hirth & Lothe, 1982), or to
understand the structure of the dislocation core (Duesbery & Richardson, 1991; Bulatov &
Cai, 2006).
Early investigations on semiconductor materials indicated the presence of electrically
charged dislocations. It was already proved by Gallagher (1952) that plastic deformation of
silicon and germanium increases their resistivity. Hall effect measurements suggested the
introduction of acceptor-type levels in n-type Ge by deformation which was explained by
negatively charged dislocation lines screened by a positive space charge region (Pearson et
al., 1954). Based on these results and a remark of Shockley that dangling bonds in the core of
an edge dislocation exist, Read (1954a,b) formulated a phenomenological theory of charged
dislocations. He introduced the concept of dislocation electron levels, the occupation ratio of
dislocation levels, and the radius of a Read cylinder surrounding each charged dislocation
and screening the linear charge localized on it. Read (1954a,b) assumed that the dislocation
states are represented by a single level or a one-dimensional band which is empty when the
dislocation is in the neutral state. This assumption is applicable only at low temperatures
(Labusch & Schröter, 1980). On the other hand, Schröter and Labusch (1969) argue that even
at higher temperatures the dislocation band is half filled in the neutral state. Furthermore,
dangling bonds does not exist in real dislocations. Numerous theoretical and experimental
investigation particularly on dislocations in silicon refer to reconstructed dislocation cores.
Therefore the electrical activity is related to defects on the dislocation core, such as kinks,
jogs, and also by point defects bound to the core or in the elastic or electric field of the
dislocation (Schröter & Cerva, 2002). While different types of dislocations are distinguished
by different core defects their electrical activity is different (Alexander & Teichler, 1991). In
addition, the concentration of point defects interacting with dislocations is doubtful even in

inclined at an angle of 60° to the dislocation line. The diamond structure corresponds to two
face-centered cubic (fcc) lattices displaced by
(
14,14,14
⁄⁄⁄)
. Hence, atoms in both lattices do
not have identical surroundings. Due to this fact, there are two distinct sets of {111} lattice
planes; the closely spaced glide subset and the widely spaced shuffle subset (Hirth & Lothe,
1982). There is a long controversial discussion about the dominant dislocation type in the
diamond structure. Early publications suggest the presence of dislocations in the shuffle set
because movement through one repeat distance on a shuffle plane breaks one covalent bond
per atomic length of dislocation (e.g. Seitz, 1952). The equivalent step on a glide plane involves
the breaking of three bonds (Amelinckx, 1982). The idea of splitting or dissociation of perfect
dislocations in the diamond structure has been commented for the first time by Shockley
(1953) and was experimentally proved later on by electron microscopy. The introduction of the
weak-beam method by Cockayne et al. (1969) has particularly shown that dislocations in
silicon are in general dissociated and glide in this extended configuration. Both the screw and
60° dislocation belonging to the glide set can dissociate into pairs of partial dislocations
bounding an intrinsic stacking fault ribbon (Ray & Cockayne, 1971; Gomez et al., 1975; Gomez
& Hirsch, 1977). On the other hand, screw and 60° dislocations of the shuffle set can only
dissociate into partials bounding an intrinsic stacking fault if there is a row of either vacancies
or interstitials associated with one of the partials (Amelinckx, 1982). Most of the evidence
indicates that the dislocations found in plastically deformed silicon belong to the glide set
(Hirsch, 1985; Alexander, 1986; Duesbery & Joós, 1996).
For the 60° dislocation a 30° partial and a 90° partial dislocation are formed through
dissociation, while the screw dislocation dissociates into two 30° partials (Gomez et al., 1974;
Heggie and Jones, 1982). These is described by the dissociation reaction (Marklund, 1979)

Crystalline Silicon – Properties and Uses
60

=

6
[
121
]


=

6
211
(4b)

holds. The 30° as well as the 90° dislocations are of the Shockley type. The dissociation result
as well in the formation of a stacking fault between both partial dislocations. The size of the
stacking fault, i.e. the width of the splitting of the perfect dislocations d
0
, depends in a stress
free crystal on the stacking fault energy 
SF
and the repulsion force F of the partial dislocations


=




(5)


=


1+

−
1−
1+
∙


2


(7)
with  being a geometric factor and  = 
1
/
2
as the ratio of mobilities 
j
of both partial
dislocations. (a) (b)
Fig. 1. Models of the core structure of an unreconstructed (a) and a reconstructed 30° partial
dislocation (b) according to Northrup et al. (1981) and Marklund (1983).


neighbours plus two more neighbours at a somewhat greater distance. This reconstruction is
known as the quasi-fivefold reconstruction. Simulations, however, indicate that the quasi-
fivefold configuration was higher in energy (Bigger et al., 1992). Benetto et al. (1997)
proposed a new core reconstruction for the 90° partial dislocation with double the
periodicity along the dislocation line (figure 2b). They found also that this reconstruction
has a lower potential energy than the single period reconstruction. Further simulations, (a) (b)
Fig. 2. Models of the core structure of a single period (a) and a double period reconstruction
of a 90° partial dislocation (b) according to Bulatov et al. (2001).

Crystalline Silicon – Properties and Uses
62
however, have shown that the energy differences between the single and double period
structures are very close (Lehto & Öberg, 1998).
3. Electronic properties of dislocations in silicon
Dislocations interfere the translational symmetry of the crystal. As a consequence energy
levels in the band gap result. First analyses were done by Read (1954a, b) who concerned
with long-range screening and occupation statistics in the presence of the macroscopic band
bending due to the dislocation. Based on early experiments of the plastic deformation of
heavily doped p-type Ge single crystals (Gallagher, 1952; Pearson et al., 1954) Read
concluded that only an acceptor level is introduced by edge dislocation. According to this
model the dislocation is negatively charged. The line charge of the dislocation is screened by
ionized donor atoms in a cylinder. Free electrons cannot penetrate this space charge cylinder
and are scattered by specular reflection at its surface. For the position of the energy level of
the neutral dislocation Read (1954a) obtained a value of 0.2 eV below the conduction band.
The acceptor model of the dislocation states was not confirmed by measurements on p-type
Ge and Si with lower doping levels (Schröter, 1969; Weber et al., 1968). It was concluded that
dislocations can act as acceptors and as donors and consequently a partially filled band was

(
∙∙
|


−

|)
/

(9)
In Eq. (8) N
D
and N
A
are the concentrations of donors and acceptors, respectively. Veth and
Lannoo (1984) pointed out that Eq. (8) is linear with p, which fits the experimental data with
Read´s model and corresponds to the line charge model by Labusch & Schröter (1980). There
are several problems that have to be solved by any model of the charged dislocation core.
One is the electrostatic potential around a charged dislocation. Another is the mobility of the
charges on the dislocation line.
Computer simulations result in a number of deep levels related to defects on the dislocation
core (Alexander & Teichler, 1991). The energy levels depend strongly on the geometry of the
defects. For instance, the structure and resulting energy levels of 30° partial dislocations
were studied by Marklund (1979), Northrup et al. (1981), Chelikowsky (1982), and Csányi et
al. (2000). Deep levels related to 60° or 90° partial dislocations were summarized by
Alexander & Teichler, 1991). All the computer simulations clearly demonstrate that deep
levels are caused by core bond reconstruction and reconstruction defects. Most of the

Structure and Properties of Dislocations in Silicon

ij
denotes the components of the strain tensor. Considering one minimum in the
centre of the Brillouin zone and assuming an elastically isotropic material as an
approximation, the shift of the conduction band minimum is given by the trace of the strain
tensor and one component of the deformation potential tensor, Ξ
d
(Schröter & Cerva, 2002):
Δ

=


∙Ξ

(1−2)
2(1−)
∙
Θ


(11)
In polar coordinate system  means the angle between  and b
e
, the edge component of the
Burgers vector. If Ξ
d
is positive, the conduction band edge is lowered in the compressed
region of an edge dislocation and increases in its tensile region. The behavior is reverse for
negative values of Ξ
d

arrangements (for instance, Schröter & Cerva, 2002; Alexander & Teichler, 2000). Hall effect
measurement was primarily applied to verify the electrical activity of dislocations and to
propose first models (Gallagher, 1952; Read, 1954a, b; Schröter & Labusch, 1969). Electron
paramagnetic resonance (EPR) spectroscopy provides substantial information about the
structure and, in combination with other techniques, electronic core defects (Kisielowski-