84
i
A
F
n
N
ln
q
T.k
=Φ
(4.3)
where:
d
max
– depletion layer maximum width
ε
Si
– permittivity of silicon
φ
F
– Fermi potential of semiconductor
q – electron charge magnitude
k – Boltzmann’s constant
T – absolute temperature
Figure 11 – The MOS capacitor with P substrate energy band
diagram.
Therefore, this confirms that C-V curves behavior observed
for high temperature application does not depend on t
ox
thickness. However, accurate investigations will be done in
order to understand the mechanisms that appear in MOS
structure operating in such conditions.
5. CONCLUSIONS
These initial studies of the MOS capacitor operating at high
temperatures indicate that the doping substrate concentration
influences on high frequency C-V curves behavior.
It was observed that for the gate voltage higher than 0V, the
capacitance values change as the temperature increases. Besides
that, it was also noticed that for lower doping substrate
concentration the high frequency C-V curves behavior changes,
indicating that the capacitance due to the substrate significantly
influence in these conditions (bias and temperature).
The second peak that was observed in the high frequency
C-V curves operating at high temperatures needs an accurate
studies in order to elucidate the physical effects that create this
deviation observed in MOS capacitor operating at such
conditions.
6. REFERENCES
[1] McDonnald, J.A., “Proving they can take the heat”, HT
Report, III-Vs Review, Vol. 9, No 5, pp. 63-67, 1996.
[2] Bellodi, M., Estudo das Componentes e Modelagem da
Correntes de Fuga em Dispositivos SOI MOSFET Operando e
Altas Temperaturas, Doctor Thesis, USP, São Paulo, 2001.
[3] Grabinski, W., Stricker, A., Fichtner, W., “A Versatile Setu
for Semiconductor Testing up to 550ºC”, HITEC 1998, USA
pp. 143-147, 1998.
[4] Osman, A.A., Osman, M.A., “Investigation of Hig
Temperature Effects on MOSFET Transconductance (gm)”,
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[5] ATLAS Device Simulation Framework, version 5.10.0.R
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[6] Mizuno, K., Ohta, K., Kitagawa, F., Nagase, H., “Analo
CMOS Integrated Circuits for High-Temperature Operatio
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41-44, 1998.
[7] Neudeck, P.G., Okojie, R.S., Chen, L.Y., “High
Temperature Electronics – A Role for Wide Bandga
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[8] Johnson, R.W., Evans, J.L., Jacobsen, P., Thompson, J.R.
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[10] Zhou, F., Kotru, S., Pandey, R.K., “Pulsed laser-deposite
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[11] Streetman, B.G., Banerjee, S.K., Solid State Electroni
Devices 6
th
Edition, Prentice Hall, New Jersey, 2000.
[12] Martino, J.A., Pavanello, M.A., Verdonck, P.B.
Caracterização Elétrica de Tecnologia e Dispositivos MOS
Thomson, São Paulo, 2003.
[13] Kano, K., Semiconductor Devices, Prentice Hall, Ne
Jersey, 1998.
d
max
s
V
OX
F
Si
M
E
c
E
v
E
i
E
Fs
V
G
=V
T
E
Fm