Lecture 7.0Lecture 7.0

Device Physics

Electronic DevicesElectronic Devices

Passive Components

Resistance (real #)– Conductor– Resistor– Battery

Active Components

Reactance (Imaginary #)– Capacitor– Inductor– Diode– Transistor– Surge Protector

ConductorsConductors

Materials– Metal Interconnects

• Wire Lines– W, Al, Cu

• Vias– W

– Gates• W

Resistance,

R= L/A

CapacitanceC=oA/d

Metal JunctionsMetal Junctions

Metal Interconnects• Wire Lines

– W, Al, Cu

• Vias– W

– Gates• W

Equilibration of Ef

Difference in Work Functions

ResistorsResistors

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

CapacitanceCapacitance

C=oA/d

=C/Co

=1+e

e =electric susceptibility

CapacitorCapacitor

Allows AC signal to pass

Stops DC part of signal

Slow build-up of charge

Timing Circuits Signal Integration

Reactance Imaginary # for

Resistance

Capacitors in Silicon ChipsCapacitors in Silicon Chips

On chip

– SiO2

– Si3N4

On Circuit Board

– BaTiO3

– (Pb,La)TiO3

Materials– SiO2

– Si3N4

– BaTiO3

– (Pb,La)TiO3

Dielectric ConstantDielectric Constant

opt= (V/C)2

opt= n2

n=Refractive index

Circuit Board CapacitorCircuit Board Capacitor

Ni ElectrodesBaTiO3 Dielectric = 2000-3000

On Chip Capacitor (Memory Chip)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.

W et G ate O x

D ie lectric C ell N itride

N ative O xide

C onta iner C e ll - C om bo P o ly17 M asking Leve l

Top C e ll P la te - Ins itu P o ly3(52 M asking Leve l)

Void

InductorInductor

What is it?– Coil of wire

Not used on ChipOn Circuit Board

– Used oftenReactance

– (imaginary # for resistance)

P-n junctionP-n junction

One way flow of current – Diode bridge

• Converts AC to DC

Photo Diode Laser

P-N Junction - DiodeP-N Junction - DiodeN-type P-type

Ef

Ef

DiodesDiodes

P-n junction

One way flow of current – Diode bridge

• Converts AC to DC

Photo Diode Laser

Poisson’s EquationPoisson’s Equation

2U = -/( o )• N side

n= - e Nd

• P side p=+ e Na

• U=Φ = Potential (volt)

Poisson Eq. dPoisson Eq. d22UU/dx/dx2 2 = -= -/(/(oo) )

]ln[][

])exp[(

])exp[(

])exp[(

])exp[(

2i

daB

Bfvp

Bfvn

Bgfcn

Bgfcp

n

NN

e

Tk

TkEeNp

TkENp

TkEENn

TkeEENn

2/1)]([)(

]/)exp[()(

)()(

eEECEg

TkEEEf

dEEfEgn

ge

Bf

p

P-N Junction (Diode) – no bias VP-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 Ф.

]/)exp[( TkeEECII

nII

Bgfodrift

pdriftdiffusion

Diode with Applied VoltageDiode with Applied Voltage

I

V Reverse Bias Forward Bias

- Io

P-N Junction (Diode) – with forward bias VP-N Junction (Diode) – with forward bias V

Current to equilibrated electrons from p zone to n zone.

1)/exp(

]/)exp[(

TkeVIIII

TkeVeEECI

Bodriftdiffusion

Bgfdiffusion

P-N Junction (Diode) – with P-N Junction (Diode) – with reversereverse bias V bias V

Current to equilibrated electrons from p zone to n zone.

1)/exp(

]/)exp[(

TkeVIIII

TkeVeEECI

Bodriftdiffusion

Bgfdiffusion

Diode Avalanche BreakdownDiode Avalanche Breakdown

Diode – Diode – equivalent equivalent circuitcircuit