Lecture 7.0 Device Physics

Electronic Devices Passive Components Resistance (real #) –Conductor –Resistor –Battery Active Components Reactance (Imaginary #) –Capacitor –Inductor –Diode –Transistor –Surge Protector

Conductors Materials –Metal Interconnects Wire Lines –W, Al, Cu Vias –W –Gates W Resistance, R=  L/A Capacitance C=  o A/d

Metal Junctions Metal Interconnects Wire Lines –W, Al, Cu Vias –W –Gates W Equilibration of E f Difference in Work Functions

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

Capacitance C=  o A/d  =C/C o  =1+  e  e = electric susceptibility

Capacitor 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 Chips On chip –SiO 2 –Si 3 N 4 On Circuit Board –BaTiO 3 –(Pb,La)TiO 3 Materials –SiO 2 –Si 3 N 4 –BaTiO 3 –(Pb,La)TiO 3

Dielectric Constant   opt = (V/C) 2  opt = n 2 n=Refractive index

Circuit Board Capacitor Ni Electrodes BaTiO 3 Dielectric =

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.

Void

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

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

P-N Junction - Diode N-type P-type EfEf EfEf

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

Poisson’s Equation  2 U = -  /(   o ) N side –  n = - e N d P side –  p =+ e N a U=Φ = Potential (volt)

Poisson Eq. d 2 U/dx 2 = -  /(  o )

P-N Junction (Diode) – no bias V Thickness of depletion layers –N d l n = N p l p Current to equilibrate electrons from p zone to n zone due to competition of diffusion vs drift due to contact Ф.

Diode with Applied Voltage

P-N Junction (Diode) – with forward bias V Current to equilibrated electrons from p zone to n zone.

P-N Junction (Diode) – with reverse bias V Current to equilibrated electrons from p zone to n zone.

Diode Avalanche Breakdown

Diode – equivalent circuit