ME 381R Lecture 13-14 Semiconductor Devices and Thermal Issues
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Transcript of ME 381R Lecture 13-14 Semiconductor Devices and Thermal Issues
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ME 381R Lecture 13-14
Semiconductor Devices and Thermal Issues
Dr. Li Shi
Department of Mechanical Engineering The University of Texas at Austin
Austin, TX 78712www.me.utexas.edu/~lishi
Reading: 1-7-1 & Ch. 7 in Tien et al.
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p-n Junction w/o Bias Depletion Region
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Biased p-n Junction
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Metal-Oxide-Semiconductor (MOS) Capacitor
: Electron AffinityWork Function
Energy Band Diagram before making contact
n-type
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MOS Capacitor W/O Bias (Special Case: M = S)
Energy Band Diagram after making contact
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Accumulation and Depletion of Majority Carriers
VG
Vi
eVGVS
Block Charge Diagram
Very thin
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Inversion Layer: C majority carrier >C minority carrier
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Metal-Oxide-Semiconductor Field-Effect Transistor (MOSFET)
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Ideal MOSFET
VG>0
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Pinch-Off & IV
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Thermal Circuit
Particle transport theory
Fourier’s law of heat conduction
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Joule Heating inHigh-Field Devices
Localized heat generationnear the pinch-off point
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X-Y-Z Actuator
Thermometry of Nanoelectronics
Sample
Temperature Sensor
Laser
Atomic Force Microscope (AFM) + Thermal Probe
CantileverDeflectionSensing
Thermal
X
TTopographic
X
Z
Scanning Thermal Microscope:
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Microfabricated Probes
Pt-Cr Junction
Shi, Kwon, Miner, Majumdar, J. MicroElectroMechanical Sys., 10, p. 370 (2001)
10 m
Pt Line
Cr Line
TipLaser Reflector
SiNx Cantilever
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Self Heating Effect on I-V
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Optical Phonon Emission at High Field
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Heat Transfer Path
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Governing Equations for Electro-Thermal Simulation of Devices
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Example
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Computation Scheme
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Results
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Electric Field
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Electron Temperature
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Phonon Temperature