Department of Electronics Semiconductor Devices 27 Atsufumi
Hirohata 11:00 Thursday, 4/December/2014 (P/T 005)
Slide 2
Exercise 6 Calculate the depletion layer capacity at a reverse
bias V R = 0.5 V in a Au/n-Si Schottky diode. Assume the following
parameters: Au work function: M = 4.80 eV n-region: doping density
of N D = 1 10 21 m -3 Si electron affinity: = 4.05 eV Si Fermi
level: E F = E C 0.15 eV permittivity: = 0 = 12.0 8.854 10 -12 F/m
and q = 1.6 10 -19 C. q(V bi + V R ) Depletion layer EFEF qV R ECEC
EVEV
Slide 3
Answer to Exercise 6 The built-in potential can be calculated
as For an n-type contact, : Ohmic contact : Schottky contact with
the barrier height of Hence, By substituting the given parameters,
Depletion layer capacity C is
Slide 4
27 Metal Oxide Semiconductor Junction Bias application Surface
space-charge MOS FET
Slide 5
Realistic Schottky Barrier Image force and Shottky barrier : *
S. M. Sze, Physics of Semiconductor Devices (Wiley, New York,
2006).
Slide 6
Metal Oxide Semiconductor Junction n-type semiconductor at V =
0 : * S. M. Sze, Physics of Semiconductor Devices (Wiley, New York,
2006). p-type semiconductor at V = 0 :
Slide 7
Metal Oxide Semiconductor (MOS) p-type Si / SiO 2 / poly-Si : *
http://www.wikipedia.org/ In 2007, Intel introduced p-type Si /
high-k oxides (HfO 2 etc.) / metal.
Slide 8
Bias Applications Reverse bias (accumulation) : * S. M. Sze,
Physics of Semiconductor Devices (Wiley, New York, 2006). Forward
bias (depletion) : Forward bias (inversion) :
Slide 9
Surface Space-Charge p-type semiconductor : * S. M. Sze,
Physics of Semiconductor Devices (Wiley, New York, 2006).
Slide 10
Space-Charge Variation With different surface potentials S : *
S. M. Sze, Physics of Semiconductor Devices (Wiley, New York,
2006).
Slide 11
Charge Distributions Band diagram of a metal oxide
semiconductor junction under an inversion condition : * S. M. Sze,
Physics of Semiconductor Devices (Wiley, New York, 2006). Charge
distributions : Electric field distributions : Potential
distributions :
Slide 12
MOS Field Effect Transistor (FET) One of the most popular
transistors for amplification and switching : *
http://www.wikipedia.org/
Slide 13
MOS FET Operation Current-Voltage characteristics : *
http://www.wikipedia.org/
Slide 14
MOS FET Operation Gate functionality : *
https://www.youtube.com/watch?v=DquJSQasWG0