Effect of pressure on the properties of Al-SiO₂-n-Si<Ni> structures
We investigated the effect of hydrostatic pressure on relaxation characteristics of the three-layer Al-SiO₂-n-Si<Ni> structures. It was found that 20 min exposure to a pressure of 8 kbars results in reduction of the integral density of surface states, while exerting no influence on the gen...
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Інститут фізики напівпровідників імені В.Є. Лашкарьова НАН України
2012
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Vlasov, S.I. Ovsyannikov, A.V. Ismailov, B.K. Kuchkarov, B.H. 2017-05-29T16:39:22Z 2017-05-29T16:39:22Z 2012 Effect of pressure on the properties of Al-SiO₂-n-Si<Ni> structures / S.I. Vlasov, A.V. Ovsyannikov, B.K. Ismailov, B.H. Kuchkarov // Semiconductor Physics Quantum Electronics & Optoelectronics. — 2012. — Т. 15, № 2. — С. 166-169. — Бібліогр.: 15Х назв. — англ. 1560-8034 PACS 73.40.Rw https://nasplib.isofts.kiev.ua/handle/123456789/118305 We investigated the effect of hydrostatic pressure on relaxation characteristics of the three-layer Al-SiO₂-n-Si<Ni> structures. It was found that 20 min exposure to a pressure of 8 kbars results in reduction of the integral density of surface states, while exerting no influence on the generation centers in the bulk. en Інститут фізики напівпровідників імені В.Є. Лашкарьова НАН України Semiconductor Physics Quantum Electronics & Optoelectronics Effect of pressure on the properties of Al-SiO₂-n-Si<Ni> structures Article published earlier |
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Effect of pressure on the properties of Al-SiO₂-n-Si<Ni> structures |
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Effect of pressure on the properties of Al-SiO₂-n-Si<Ni> structures Vlasov, S.I. Ovsyannikov, A.V. Ismailov, B.K. Kuchkarov, B.H. |
| title_short |
Effect of pressure on the properties of Al-SiO₂-n-Si<Ni> structures |
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Effect of pressure on the properties of Al-SiO₂-n-Si<Ni> structures |
| title_fullStr |
Effect of pressure on the properties of Al-SiO₂-n-Si<Ni> structures |
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Effect of pressure on the properties of Al-SiO₂-n-Si<Ni> structures |
| title_sort |
effect of pressure on the properties of al-sio₂-n-si<ni> structures |
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Vlasov, S.I. Ovsyannikov, A.V. Ismailov, B.K. Kuchkarov, B.H. |
| author_facet |
Vlasov, S.I. Ovsyannikov, A.V. Ismailov, B.K. Kuchkarov, B.H. |
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2012 |
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English |
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Semiconductor Physics Quantum Electronics & Optoelectronics |
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Інститут фізики напівпровідників імені В.Є. Лашкарьова НАН України |
| format |
Article |
| description |
We investigated the effect of hydrostatic pressure on relaxation characteristics
of the three-layer Al-SiO₂-n-Si<Ni> structures. It was found that 20 min
exposure to a pressure of 8 kbars results in reduction of the integral density of surface
states, while exerting no influence on the generation centers in the bulk.
|
| issn |
1560-8034 |
| url |
https://nasplib.isofts.kiev.ua/handle/123456789/118305 |
| citation_txt |
Effect of pressure on the properties of Al-SiO₂-n-Si<Ni> structures / S.I. Vlasov, A.V. Ovsyannikov, B.K. Ismailov, B.H. Kuchkarov // Semiconductor Physics Quantum Electronics & Optoelectronics. — 2012. — Т. 15, № 2. — С. 166-169. — Бібліогр.: 15Х назв. — англ. |
| work_keys_str_mv |
AT vlasovsi effectofpressureonthepropertiesofalsio2nsinistructures AT ovsyannikovav effectofpressureonthepropertiesofalsio2nsinistructures AT ismailovbk effectofpressureonthepropertiesofalsio2nsinistructures AT kuchkarovbh effectofpressureonthepropertiesofalsio2nsinistructures |
| first_indexed |
2025-11-25T04:24:24Z |
| last_indexed |
2025-11-25T04:24:24Z |
| _version_ |
1850503626774020096 |
| fulltext |
Semiconductor Physics, Quantum Electronics & Optoelectronics, 2012. V. 15, N 2. P. 166-169.
© 2012, V. Lashkaryov Institute of Semiconductor Physics, National Academy of Sciences of Ukraine
166
PACS 73.40.Rw
Effect of pressure on the properties of AlSiO2n-SiNi structures
S.I. Vlasov, A.V. Ovsyannikov, B.K. Ismailov, B.H. Kuchkarov
M. Ulugbek National University of Uzbekistan, Tashkent, Uzbekistan
E-mail: vlasov@uzsci.net
Abstract. We investigated the effect of hydrostatic pressure on relaxation characteristics
of the three-layer AlSiONiSi-nAl 2 structures. It was found that 20 min
exposure to a pressure of 8 kbars results in reduction of the integral density of surface
states, while exerting no influence on the generation centers in the bulk.
Keywords: MOS structure, hydrostatic pressure, Schottky diode.
Manuscript received 08.02.12.; revised version received 01.03.12; accepted for
publication 27.03.12; published online 15.05.12.
1. Introduction
At present many semiconductor devices and structural
elements of integrated circuits (ICs) involve the Si-based
metal-oxide-semiconductor (MOS) structures. The
characteristics of the semiconductor-oxide interface can
considerably influence the parameters of produced
devices and structural elements [1, 2].
There exists a number of papers (see, e.g., [3-7])
devoted to investigations of the effect of such external
actions as thermal treatment and -irradiation on the
parameters of interfaces. As to the effect of pressure, the
available works deal predominantly with an analysis of
the bulk properties variation in the layers of MOS
structures [8-11]. The authors of [8-10] related the
parameters variation in MOS structures subjected to a
uniaxial elastic strain to changes in the concentration and
mobility of the majority charge carriers in semi-
conductors. In [11] the observed variations of relaxation
characteristics under pressure were related to production
of defect centers in insulator layers, while in [12] these
characteristics were explained from the viewpoint of
crystallographic orientation of the semiconductor crystal.
The objective of this work was to investigate the
effect of hydrostatic pressure on the density of electron
states localized at the 2SiOSi interface.
2. Test samples
The structures to be investigated were prepared on the
basis of crystalline silicon КЭФ-5 with crystallographic
orientation (100) that is most often used in
microelectronics. Diffusion doping of silicon with Ni
was made (at a temperature T = 1200 C for 2 hours)
from metal nickel deposited onto the Si plate surface.
The Ni dopant was chosen because its introduction
influences the density of surface states distribution over
the silicon bandgap [13].
A SiO2 layer (thickness of 20003000 Å) was
grown using thermal oxidation of the silicon plates (T =
900 C for 40 min) in a chlorine-containing
environment. The MOS structures were prepared using
vacuum deposition of aluminum onto the silicon dioxide
surface. The control electrode diameter was 3 mm. The
structures made were subjected to hydrostatic pressure
up to 28 kbars (with a step of 2 kbars and retention
interval of 20 min) using a setup similar to that described
in [14]. The energy levels of nickel in silicon were
identified using the procedure described in [15]. To this
end, we made NiSi-nAu Schottky diodes using
chemical removal of the SiO2 layer and vacuum
deposition of Au.
Semiconductor Physics, Quantum Electronics & Optoelectronics, 2012. V. 15, N 2. P. 166-169.
© 2012, V. Lashkaryov Institute of Semiconductor Physics, National Academy of Sciences of Ukraine
167
3. Method of investigation
Let us write down the electrical neutrality condition for a
MOS structure:
kqNx + QP + QSS = QCS. (1)
Here k is the ohmic contact area, q is the electron charge,
N = Nm is the concentration of low-level impurity, x is
the width of the space-charge region (SCR), QP is the
charge in the inversion layer, QSS is the charge at the
surface states and QCS is the charge at the gate of the
MOS structure.
After differentiating the left and right parts of
Eq. (1) with respect to time t, we obtain the expression
that describes charge change with time:
dt
dQ
dt
dQ
dt
dQ
dt
dx
qNk CSSSP . (2)
Since the charge at the metal electrode does not
change during relaxation
0
dt
dQCS , Eq. (2) becomes
0
dt
dQ
dt
dQ
dt
dx
qNk SSP . (3)
The changes of the charge in the inversion layer
and at the surface states may be written, respectively, as
Aqkx
dt
dQP (where A is the charge carrier generation
rate in the semiconductor bulk) and Sqk
dt
dQSS (where
S is the surface charge carrier generation rate). Then
Eq. (3) takes the form
0 SqkAqkx
dt
dx
kqN (4)
or, after some simplification,
N
S
x
N
A
dt
dx
. (5)
This is a first-order differential equation. After
solving it for x, we obtain:
A
S
t
N
A
Cx
exp , (6)
where C is a constant of integration. To determine it, let
us make use of the initial condition x(t = 0) = x0 (the
SCR width value at the start of relaxation process). Then
the solution of Eq. (8) that gives the time dependence of
SCR width is
A
S
t
N
A
A
S
xx
exp0 . (7)
This result can be used for determination of the
surface and bulk generation rates by comparing it with
the experimental time dependence of the SCR width.
Using the conventional model of MOS structure, one can
show that the time dependence of measured capacitance
(without allowing for the effect of charge accumulation
in the inversion layer) is of the following form:
i
i
CtxK
KC
tC
0 . (8)
Here, K is the control electrode area, Ci is the
insulator layer capacitance, is the semiconductor
permittivity, and 0 is the electric constant. Ci is
determined from the high-frequency capacitance-voltage
characteristic. C(t) value can be determined, for any
moment t, from the experimental relaxation
characteristic of MOS structure.
4. Results and discussion
Fig. 1 shows the experimental (11) (measured at a
frequency of 250 kHz and temperature of 15 C) and
theoretical (12) capacitance vs relaxation time curves
C(t) for one of the reference AlSiONiSi-nAl 2
structures. The curves were obtained after voltage
switching V1V2 (V1 = 7 V, V2 = 14 V). The values of
the bulk (A) and surface (S) generation rates were
determined using the Eqs. (7) and (8) by applying the
optimal fitting technique: A = 3113 cms109 , S =
219 cms104 . With the above A and S values, the
calculated C(t) curve is in a good agreement with the
experimental one. Some distinction between the two
curves at the end of relaxation process is caused by the
effect of charge accumulation in the inversion layer and
increase of the probability of generated charge carrier
recapturing.
Fig. 1. Experimental (11, 21) and theoretical (12, 22)
capacitance C vs relaxation time t curves for the
AlSiONiSi-nAl 2 structures (11 and 12 – reference
structures, 21 and 22 – structures subjected to pressure).
Semiconductor Physics, Quantum Electronics & Optoelectronics, 2012. V. 15, N 2. P. 166-169.
© 2012, V. Lashkaryov Institute of Semiconductor Physics, National Academy of Sciences of Ukraine
168
Fig. 2. Distribution of the integrated density of surface states
(NSS) over the silicon bandgap for the
AlSiONiSi-nAl 2 structures (1 – reference structure,
2 – structure subjected to a pressure of 8 kbars).
The curves (21) and (22) obtained under the similar
conditions correspond to a sample subjected to
hydrostatic pressure up to 8 kbars. One can see from
Fig. 1 that the calculated curve 22 is in a good agreement
with the experimental one 21 at A =
3113 cms1098 , S = 219 cms1021 . We
consider this as an indication that, at the mentioned
pressure values, the concentration and energy
distribution of the Ni impurity centers practically do not
change, while reduction of the surface generation rate is
due to variation of the density of surface states.
To verify the above assumption, we removed (by
treating in hydrofluoric acid vapor) the SiO2 layer from
the structures subjected to pressure and then used them
to fabricate NiSi-nAu Schottky diodes. After this,
using the isothermal capacitance relaxation method [14],
we identified the Ni impurity and determined its
concentration. An analysis of the results obtained
showed the following. In all the Schottky diodes (both
reference and made on the plates subjected to pressure)
the Ni impurity level position (EC 0.4 0.03 eV and
EV + 0.2 0.03 eV) and concentration n =
312 cm1053 practically did not change. The
spread of their values for different diodes was 5-7%, i.e.,
lied within the limits of experimental errors.
We made the direct measurement of density of
surface states using the high-frequency capacitance-
voltage technique [2, 12]. For the structures subjected to
pressure, it was shown that, at energies over
EC 0.35 eV, the integrated density of surface states
lying in the silicon bandgap was smaller than that for the
reference structures (see Fig. 2).
5. Conclusion
The results obtained in this work make it possible to
conclude that subjection of the
AlSiONiSi-nAl 2 structures to a pressure up to
8 kbars for 20 min leads to restructuring of the
2SiOSi transition layer. As a result, the integrated
density of electrically active surface states decreases. At
the same time, the above pressure has no pronounced
effect on the properties of bulk generation centers.
References
1. V.E. Primachenko, S.I. Kirillova, V.A. Chernobai,
E.F. Venger, Electron states at the SiSiO2
boundary (Review) // Semiconductor Physics,
Quantum Electronics & Optoelectronics, 8(4),
p. 38-54 (2005).
2. A.P. Baraban, V.V. Bulavinov, P.P. Konorov,
Electronics of SiO2 Layers on Silicon. Publ.
Leningrad State University, 1988 (in Russian).
3. T.G. Menshikova, A.E. Bormontov, V.V. Ganja,
Effect of built-in charge fluctuations on the
electrophysical characteristics of MIS structures //
Vestnik VGU, Ser. Fizika, Matematika. No 1, p. 75-
79 (2005), in Russian.
4. C. Claeys, E. Simoen, Radiation Effects in
Advanced Semiconductor Materials and Devices.
Springer-Verlag, Berlin-Heidelberg, 2002.
5. M.N. Levin, A.V. Tatarintsev, Yu.V. Ivankov,
Modeling the effect of ionizing radiations on a
metal-insulator-semiconductor structure //
Kondensirovannye Sredy i Mezhfaznye Granitsy
4(3), p. 195-202 (2002), in Russian.
6. S.I. Vlasov, A.V. Ovsyannikov, B.N. Zaveryukhin,
Effect of ultrasonic treatment on the generation
characteristics of a semiconductor-glass interface //
Techn. Phys. Lett. 35(4), p. 312-314 (2009).
7. S.G. Dmitriev, Yu.V. Markin, Manifestations of the
deneutralization of mobile charges in SiO2 in the
spectroscopy of the silicon-oxide interface //
Semiconductors, 32(12), p. 1289-1292 (1998).
8. A.V. Ozarenko, Yu.A. Brusentsov, A.P. Korolev,
Peculiarities of tensoresistive effect in metal-
dielectric-semiconductor structure under static and
non-uniform deformation // Vestnik TGTU, 14(1),
p. 158-163 (2008), in Russian.
9. G.L. Klimchitskaya, A.B. Fedortsov,
Yu.V. Churkin, V.A. Yurova, Casimir force
pressure on the insulating layer in metal-insulator-
semiconductor structures // Physics of the Solid
State, 53(9), p. 1921-1926 (2011).
Semiconductor Physics, Quantum Electronics & Optoelectronics, 2012. V. 15, N 2. P. 166-169.
© 2012, V. Lashkaryov Institute of Semiconductor Physics, National Academy of Sciences of Ukraine
169
10. I.G. Neizvestnyi, A.A. Gridchin, The use of
stressed silicon in MOS transistors and CMOS
structures // Russian Microelectronics, 38(2), p. 71-
86 (2009).
11. S.I. Vlasov, A.A. Mamatkarimov, A.V. Ovsyan-
nikov, F.A. Saparov, Influence of pressure on
creation of microdimension inclusions at surfaces
of metal-semiconductor structures, in 9th Joint
Uzbek-Korea Symposium. Nanoscience: Problems
and Prospects. Quantum Functional Materials and
Devices, Abstracts, p. 29 (2010).
12. Cheng-Yi Peng, Ying-Jhe Yang, Yen-Chun Fu,
Ching-Fang Huang, Shu-Tong Chang, Chee Wee
Liu, Effects of applied mechanical uniaxial and
biaxial tensile strain on the flat band voltage of
(001), (110), and (111) metal-oxide-silicon
capacitors // IEEE Trans. Electron Dev. 56(8),
p. 1736-1745 (2009).
13. S.Z. Zainabidinov, S.I. Vlasov, I.N. Karimov,
Effect of nickel and -irradiation on the density of
surface states // Fiz. Tekhn. Poluprov. 20(7),
p. 1348 (1986), in Russian.
14. A.T. Gaivoronskii, Yu.I. Yakovlev, B.I. Beresnev,
D.K. Bulychev, Hydrostat LG // Pribory i Tekhnika
Eksperimenta, No 5, p. 232 (1981), in Russian.
15. L.S. Berman, S.I. Vlasov, V.F. Morozov,
Identification of residual deep impurities in
semiconductor devices using the transient
spectroscopy // Izvestiya AN SSSR. Ser. Fizika,
42(6), p. 1175-1178 (1978), in Russian.
Semiconductor Physics, Quantum Electronics & Optoelectronics, 2012. V. 15, N 2. P. 166-169.
PACS 73.40.Rw
Effect of pressure on the properties of Al(SiO2(n-Si(Ni( structures
S.I. Vlasov, A.V. Ovsyannikov, B.K. Ismailov, B.H. Kuchkarov
M. Ulugbek National University of Uzbekistan, Tashkent, Uzbekistan
E-mail: vlasov@uzsci.net
Abstract. We investigated the effect of hydrostatic pressure on relaxation characteristics of the three-layer
Al
SiO
Ni
Si
-
n
Al
2
-
-
-
structures. It was found that 20 min exposure to a pressure of 8 kbars results in reduction of the integral density of surface states, while exerting no influence on the generation centers in the bulk.
Keywords: MOS structure, hydrostatic pressure, Schottky diode.
Manuscript received 08.02.12.; revised version received 01.03.12; accepted for publication 27.03.12; published online 15.05.12.
1. Introduction
At present many semiconductor devices and structural elements of integrated circuits (ICs) involve the Si-based metal-oxide-semiconductor (MOS) structures. The characteristics of the semiconductor-oxide interface can considerably influence the parameters of produced devices and structural elements [1, 2].
There exists a number of papers (see, e.g., [3-7]) devoted to investigations of the effect of such external actions as thermal treatment and (-irradiation on the parameters of interfaces. As to the effect of pressure, the available works deal predominantly with an analysis of the bulk properties variation in the layers of MOS structures [8-11]. The authors of [8-10] related the parameters variation in MOS structures subjected to a uniaxial elastic strain to changes in the concentration and mobility of the majority charge carriers in semiconductors. In [11] the observed variations of relaxation characteristics under pressure were related to production of defect centers in insulator layers, while in [12] these characteristics were explained from the viewpoint of crystallographic orientation of the semiconductor crystal.
The objective of this work was to investigate the effect of hydrostatic pressure on the density of electron states localized at the
2
SiO
Si
-
interface.
2. Test samples
The structures to be investigated were prepared on the basis of crystalline silicon КЭФ-5 with crystallographic orientation (100) that is most often used in microelectronics. Diffusion doping of silicon with Ni was made (at a temperature T = 1200 (C for 2 hours) from metal nickel deposited onto the Si plate surface. The Ni dopant was chosen because its introduction influences the density of surface states distribution over the silicon bandgap [13].
A SiO2 layer (thickness of 2000(3000 Å) was grown using thermal oxidation of the silicon plates (T = 900 (C for 40 min) in a chlorine-containing environment. The MOS structures were prepared using vacuum deposition of aluminum onto the silicon dioxide surface. The control electrode diameter was 3 mm. The structures made were subjected to hydrostatic pressure up to 2(8 kbars (with a step of 2 kbars and retention interval of 20 min) using a setup similar to that described in [14]. The energy levels of nickel in silicon were identified using the procedure described in [15]. To this end, we made
Ni
Si
-
n
Au
-
Schottky diodes using chemical removal of the SiO2 layer and vacuum deposition of Au.
3. Method of investigation
Let us write down the electrical neutrality condition for a MOS structure:
kqNx + QP + QSS = QCS.
(1)
Here k is the ohmic contact area, q is the electron charge, N = Nm is the concentration of low-level impurity, x is the width of the space-charge region (SCR), QP is the charge in the inversion layer, QSS is the charge at the surface states and QCS is the charge at the gate of the MOS structure.
After differentiating the left and right parts of Eq. (1) with respect to time t, we obtain the expression that describes charge change with time:
dt
dQ
dt
dQ
dt
dQ
dt
dx
qN
k
CS
SS
P
=
+
+
.
(2)
Since the charge at the metal electrode does not change during relaxation
÷
ø
ö
ç
è
æ
=
0
dt
dQ
CS
, Eq. (2) becomes
0
=
+
+
dt
dQ
dt
dQ
dt
dx
qN
k
SS
P
.
(3)
The changes of the charge in the inversion layer and at the surface states may be written, respectively, as
Aqkx
dt
dQ
P
=
(where A is the charge carrier generation rate in the semiconductor bulk) and
Sqk
dt
dQ
SS
=
(where S is the surface charge carrier generation rate). Then Eq. (3) takes the form
0
=
+
+
Sqk
Aqkx
dt
dx
kqN
(4)
or, after some simplification,
N
S
x
N
A
dt
dx
+
=
-
.
(5)
This is a first-order differential equation. After solving it for x, we obtain:
A
S
t
N
A
C
x
-
÷
ø
ö
ç
è
æ
-
=
exp
,
(6)
where C is a constant of integration. To determine it, let us make use of the initial condition x(t = 0) = x0 (the SCR width value at the start of relaxation process). Then the solution of Eq. (8) that gives the time dependence of SCR width is
A
S
t
N
A
A
S
x
x
-
÷
ø
ö
ç
è
æ
-
÷
ø
ö
ç
è
æ
+
=
exp
0
.
(7)
This result can be used for determination of the surface and bulk generation rates by comparing it with the experimental time dependence of the SCR width. Using the conventional model of MOS structure, one can show that the time dependence of measured capacitance (without allowing for the effect of charge accumulation in the inversion layer) is of the following form:
(
)
(
)
i
i
C
t
x
K
KC
t
C
+
ee
=
0
.
(8)
Here, K is the control electrode area, Ci is the insulator layer capacitance, ( is the semiconductor permittivity, and (0 is the electric constant. Ci is determined from the high-frequency capacitance-voltage characteristic. C(t) value can be determined, for any moment t, from the experimental relaxation characteristic of MOS structure.
4. Results and discussion
Fig. 1 shows the experimental (11) (measured at a frequency of 250 kHz and temperature of (15 (C) and theoretical (12) capacitance vs relaxation time curves C(t) for one of the reference
Al
SiO
Ni
Si
-
n
Al
2
-
-
-
structures. The curves were obtained after voltage switching V1(V2 (V1 = 7 V, V2 = 14 V). The values of the bulk (A) and surface (S) generation rates were determined using the Eqs. (7) and (8) by applying the optimal fitting technique: A =
3
1
13
cm
s
10
9
-
-
´
, S =
2
1
9
cm
s
10
4
-
-
´
. With the above A and S values, the calculated C(t) curve is in a good agreement with the experimental one. Some distinction between the two curves at the end of relaxation process is caused by the effect of charge accumulation in the inversion layer and increase of the probability of generated charge carrier recapturing.
Fig. 1. Experimental (11, 21) and theoretical (12, 22) capacitance C vs relaxation time t curves for the
Al
SiO
Ni
Si
-
n
Al
2
-
-
-
structures (11 and 12 – reference structures, 21 and 22 – structures subjected to pressure).
Fig. 2. Distribution of the integrated density of surface states (NSS) over the silicon bandgap for the
Al
SiO
Ni
Si
-
n
Al
2
-
-
-
structures (1 – reference structure, 2 – structure subjected to a pressure of 8 kbars).
The curves (21) and (22) obtained under the similar conditions correspond to a sample subjected to hydrostatic pressure up to 8 kbars. One can see from Fig. 1 that the calculated curve 22 is in a good agreement with the experimental one 21 at A =
(
)
3
1
13
cm
s
10
9
8
-
-
´
-
, S =
(
)
2
1
9
cm
s
10
2
1
-
-
´
-
. We consider this as an indication that, at the mentioned pressure values, the concentration and energy distribution of the Ni impurity centers practically do not change, while reduction of the surface generation rate is due to variation of the density of surface states.
To verify the above assumption, we removed (by treating in hydrofluoric acid vapor) the SiO2 layer from the structures subjected to pressure and then used them to fabricate
Ni
Si
-
n
Au
-
Schottky diodes. After this, using the isothermal capacitance relaxation method [14], we identified the Ni impurity and determined its concentration. An analysis of the results obtained showed the following. In all the Schottky diodes (both reference and made on the plates subjected to pressure) the Ni impurity level position (EC ( 0.4 ( 0.03 eV and EV + 0.2 ( 0.03 eV) and concentration n =
(
)
3
12
cm
10
5
3
-
´
-
practically did not change. The spread of their values for different diodes was 5-7%, i.e., lied within the limits of experimental errors.
We made the direct measurement of density of surface states using the high-frequency capacitance-voltage technique [2, 12]. For the structures subjected to pressure, it was shown that, at energies over EC ( 0.35 eV, the integrated density of surface states lying in the silicon bandgap was smaller than that for the reference structures (see Fig. 2).
5. Conclusion
The results obtained in this work make it possible to conclude that subjection of the
Al
SiO
Ni
Si
-
n
Al
2
-
-
-
structures to a pressure up to 8 kbars for 20 min leads to restructuring of the
2
SiO
Si
-
transition layer. As a result, the integrated density of electrically active surface states decreases. At the same time, the above pressure has no pronounced effect on the properties of bulk generation centers.
References
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© 2012, V. Lashkaryov Institute of Semiconductor Physics, National Academy of Sciences of Ukraine
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