The double Gaussian distribution of barrier heights in Al / TiO 2 / p -Si (metal-insulator-semiconductor) structures at low temperatures
The current-voltage ( I - V ) characteristics of Al / TiO 2 / p -Si metal-insulator-semiconductor (MIS) structures have been investigated in the temperature range of 80-300 K. An abnormal decrease in the zero bias barrier height (BH) ( ϕ b 0 ) and an increase in the ideality factor ( n ) with decrea...
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Published in | Journal of applied physics Vol. 104; no. 1; pp. 014501 - 014501-6 |
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Main Authors | , , , |
Format | Journal Article |
Published |
American Institute of Physics
02.07.2008
|
Online Access | Get full text |
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Summary: | The current-voltage
(
I
-
V
)
characteristics of
Al
/
TiO
2
/
p
-Si
metal-insulator-semiconductor (MIS) structures have been investigated in the temperature range of 80-300 K. An abnormal decrease in the zero bias barrier height (BH)
(
ϕ
b
0
)
and an increase in the ideality factor
(
n
)
with decreasing temperature have been explained on the basis of the thermionic emission (TE) theory with Gaussian distribution (GD) of the BHs due to the BH inhomogeneities. The temperature dependence of the experimental
I
-
V
data of the
Al
/
TiO
2
/
p
-Si
(MIS) structures has revealed the existence of a double GD with mean BH values
(
ϕ
¯
b
0
)
of 1.089 and 0.622 eV and standard deviations
σ
s
of 0.137 and 0.075 V, respectively. Thus, the modified
ln
(
I
0
/
T
2
)
−
q
2
σ
0
2
/
2
(
k
T
)
2
versus
q
/
k
T
plot gives
ϕ
¯
b
0
values and Richardson constants
(
A
∗
)
as 1.108 and 0.634 eV and 31.42 and
23.83
A
/
cm
2
K
2
, respectively, without using the temperature coefficient of the BH. The value of the effective Richardson constant of
31.42
A
/
cm
2
K
2
is very close to the theoretical value of
32
A
/
cm
2
K
2
for
p
-Si. As a result, the temperature dependence of the forward bias
I
-
V
characteristics of the
Al
/
TiO
2
/
p
-Si
(MIS) structure can be successfully explained on the basis of the TE mechanism with a double GD of the BHs. |
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ISSN: | 0021-8979 1089-7550 |
DOI: | 10.1063/1.2952028 |