Device Physics

1
Lecture 7.0

• Device Physics

2
Electronic Devices

• Passive Components
• Resistance (real )
• Conductor
• Resistor
• Battery

• Active Components
• Reactance (Imaginary )
• Capacitor
• Inductor
• Diode
• Transistor
• Surge Protector

3
Conductors
Resistance, R ? L/A Capacitance C??oA/d

• Materials
• Metal Interconnects
• Wire Lines
• W, Al, Cu
• Vias
• W
• Gates
• W

4
Metal Junctions

• Metal Interconnects
• Wire Lines
• W, Al, Cu
• Vias
• W
• Gates
• W

Equilibration of Ef Difference in Work Functions
5
Resistors

• On Chip
• Low resistance
• Silicon with dopants at a particular
  concentration
• High resistance
• Insulator with a specific size
• Gate oxide-tunneling junction
• Oxide Insulator between two conductors
• Circuit Board Resistors

6
Capacitance
C??oA/d ?C/Co ?1?e ?e electric
susceptibility
7
Capacitor

• Allows AC signal to pass
• Stops DC part of signal
• Slow build-up of charge
• Timing Circuits
• Signal Integration

• Reactance
• Imaginary for Resistance

8
Capacitors in Silicon Chips

• On chip
• SiO2
• Si3N4
• On Circuit Board
• BaTiO3
• (Pb,La)TiO3

• Materials
• SiO2
• Si3N4
• BaTiO3
• (Pb,La)TiO3

9
Dielectric Constant
???? ?opt (V/C)2 ?opt n2 nRefractive index
10
Circuit Board Capacitor
Ni Electrodes BaTiO3 Dielectric 2000-3000
11
On Chip Capacitor (Memory Chip)

• An electric circuit element used to temporarily
  STORE a charge, consisting of TWO CONDUCTIVE
  plates separated and insulated from each other by
  a DIELECTRIC.

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Void
13
Inductor

• What is it?
• Coil of wire
• Not used on Chip
• On Circuit Board
• Used often
• Reactance
• (imaginary for resistance)

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P-n junction

• One way flow of current
• Diode bridge
• Converts AC to DC
• Photo Diode Laser

15
P-N Junction - Diode

• N-type P-type

Ef
Ef
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Diodes

• P-n junction
• One way flow of current
• Diode bridge
• Converts AC to DC
• Photo Diode Laser

17
Poissons Equation

• ?2U -?/(? ?o )
• N side
• ?n - e Nd
• P side
• ?p e Na
• UF Potential (volt)

18
Poisson Eq. d2U/dx2 -?/(??o)
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P-N Junction (Diode) no bias V

• Thickness of depletion layers
• Nd ln Np lp
• Current to equilibrate electrons from p zone to n
  zone due to competition of diffusion vs drift due
  to contact ?.

20
Diode with Applied Voltage
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P-N Junction (Diode) with forward bias V

• Current to equilibrated electrons from p zone to
  n zone.

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P-N Junction (Diode) with reverse bias V

• Current to equilibrated electrons from p zone to
  n zone.

23
Diode Avalanche Breakdown
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Diode equivalent circuit