Download Electronics

Electronics
- lectures for Mechanical Engineering
Dr. Bogusław Boratyński
Faculty of Microsystems Electronics and Photonics,
Wroclaw University of Technology,
2011
The course syllabus
Office:
Room 104, M-4 - campus at ul. Długa 61,
Room 306a, C-2 - consulting hours only
[email protected]
Lecture
Laboratory
R. 303, C-2
R. 218/413, C-2
The course syllabus
Course topics:
1. Electric and electronic circuits. Electronic components.
2. Properties of semiconductor materials. Energy band model.
3. Electronic sensors: thermistors, photoresistors, hallotrons.
4. The p-n junction: operation principles, the I-V characteristic.
5. Temperature effects in the p-n junction. A p-n diode thermometer.
6. Light effects in the p-n junction. Photodiodes, solar cells.
7. Types of semiconductor diodes, the parameters and applications.
8. Midterm test. Visit to the device processing laboratory.
9. Bipolar transistors; operation principles, basic configurations.
10. Bipolar transistors; static I-V characteristics, CE amplifier circuit.
11. Switching devices: thyristors, triacs, diacs.
12. FET devices: JFET, MOSFET.
13. Optoelectronic devices: LED, laser diode, photocouplers.
14. Integrated circuits: op-amp, logic gates, memories.
15. Final test.
The course syllabus
Laboratory experiments (Rooms: 218/413, C-2):
1.
2.
3.
4.
5.
Introduction to the laboratory equipment. Labwork regulations.
The p-n junction I-V characteristics. Rectifying diodes, LEDs.
Bipolar transistor (BJT) dc characteristics and an amplifier circuit.
Optoelectronic devices. BJT as a current switch.
Digital integrated circuits (TTL, CMOS).
Grading policy - lecture:
Midterm test
40%
Final test
60%
Minimum score to pass: 50%
- laboratory:
Accomplishment of all experiments;
that includes attendance, quizzes,
experimental work and report submission.
The course syllabus
Basic literature and figure sources:
Lecture notes , Laboratory instructions,
G. Rizzoni, Fundamentals of Electrical Engineering, McGraw-Hill
R. F. Pierret, Semiconductor Device Fundamentals, Addison-Wesley Publ.,
B.G.Streetman, Solid State Electronic Devices, Prentice-Hall,
D.Bell, Fundamentals of Electric Circuits, Oxford Univ. Press,
Additional literature:
Giorgio Rizzoni, Principles and Applications of Electrical Eng., McGraw-Hill
W. Marciniak, Przyrządy półprzewodnikowe i układy scalone, WNT,
A. Świt, J. Pułtorak, Przyrządy półprzewodnikowe, WNT,
B. Streetman, Przyrządy półprzewodnikowe, WNT
Outline
General outline of the course:
1. Circuits - electric and electronic circuits
Electronic components (passive): R, L, C
2. Parameters of semiconductors
3. Electronic devices (active components): diodes, transistors,
thyristors and many others …
- Integrated circuits: digital & analogue
4. Optoelectronic devices and circuits
Semiconductor crystal structure
Chapter 1. Electronic circuits, electronic components
Topics:
Electric and electronic circuits
Resistors, capacitors, inductors
Circiut diagrams, symbols
Electric circuit
How to build an electronic circuit? – a recipe:
2-DEG
Source: D.Bell, Fundamentals of Electric Circuits, Oxford Univ. Press
Electronic circuit
How to build an electronic circuit? – a recipe:
hn
2-DEG
LED
device
Source: D.Bell, Fundamentals of Electric Circuits, Oxford Univ. Press
Electronic circuits
Power
supply
• Signal -usually AC (ac)
Load
SIGNAL
Input
Output
• Power supply – usually DC (dc)
DC and AC signals,
DC signal
AC signal
Source: D.Bell, Fundamentals of Electric Circuits, Oxford Univ. Press
Electronic circuits
How to build an electronic circuit? – the measurements:
Source: D.Bell, Fundamentals of Electric Circuits, Oxford Univ. Press
Electronic components, cables, connectors
Cables, interconnections - conductors (copper, gold plated)
printed circuit boards – PCB
multilayer – laminated boards
Source: D.Bell, Fundamentals of Electric Circuits, Oxford Univ. Press
Electronic components, Resistors
R [ , k, M]
Source: Wiki
Electronic components, Resistors
Ohm’s Law
• R= V/I - resistance
• G=1/R - conductance
• I= GV - current
V=U=E - voltage
R [ , k, M]
e.g. 22, 3.3k, 10M
Source: D.Bell, Fundamentals of Electric Circuits, Oxford Univ. Press
1k
Electronic components, Capacitors
C – capacitance
Y=G+j wC –
complex
admittance
Z= 1/Y - complex impedance
 1/(wC) = Zc [] - equivalent
impedance of C

•
w= 2pf, f - signal frequency
f=1kHz, C=1mF,
Z = 160 
f=100kHz, C=1mF, Z = 1.6 
1u
222 =
22x102pF,
0.039 = 0.039mF =39nF
Source: D.Bell, Fundamentals of Electric Circuits, Oxford Univ. Press
(1 mF )
Electronic components, Capacitors
Source: Wiki
Electronic components, Capacitors
Types of caps
Source: D.Bell, Fundamentals of Electric Circuits, Oxford Univ. Press
Electrolytic capacitors
Polarization required,
for reverse bias,
may explode!
Umax is specified
Electronic components, Inductances
Types of inductances - coils
L – inductance
Z=R+j wL – complex
impedance
wL = ZL [] – equivalent
impedance of L
w= 2pf, f - signal frequency
f=100Hz, L=1mH,
Z = 0.63 
f=100kHz, L=1mF, Z = 630 
1m
(1 mH)
L [nH, mH, mH]
Source: D.Bell, Fundamentals of Electric Circuits, Oxford Univ. Press
Electronic components, Inductances
Inductances - coils
Source: Wiki
Electronic components, Inductances
Types of inductances - coils
Source: D.Bell, Fundamentals of Electric Circuits, Oxford Univ. Press
Electronic components, Transformers
Types of mutual inductances :
- transformer
Source: D.Bell, Fundamentals of Electric Circuits, Oxford Univ. Press
- autotransformer
Electronic components, Transformers
- transformer winding connections
-
- suitable for full-wave
two-diode rectifier
Source: D.Bell, Fundamentals of Electric Circuits, Oxford Univ. Press
DC and AC signals, rms value
root mean square (rms) value
Urms, Irms – for a sinewave signal
true rms value for
an arbitrary waveform ac signal
dc and ac signals
Source: D.Bell, Fundamentals of Electric Circuits, Oxford Univ. Press
Source: D.Bell, Fundamentals of Electric Circuits, Oxford Univ. Press
Active electronic components (semiconductor devices).
Diodes, Transistors, Integrated circuits.
Discrete
transistors
300mln transistors
f =3 GHz
Design rule
90 nm – 32nm
Processor
IBM PowerPC
Usupply = 3 V
I1Tr = 0,1µA =100nA
P1Tr = 0,3 10-6 W = 0,3µW
P Total = 100W
MOSFET pair - CMOS
single power
transistor
GSM base station
Usupply = 60 V, I = 3 A
P=100 W
f =3 GHz
Semiconductor crystal structure
Chapter 2. Semiconductors
Si, Ge - elemental
GaAs, InP, GaN, SiC – compounds (binary III-V)
AlGaAs, InGaAs, AlGaN - compounds (ternary III-V)
ZnS, CdTe, CdS – compounds (binary II-VI)
Semiconductor crystal structure
semiconductor wafer - substrate
Si, Ge
GaAs, InP, GaN
SiC
Semiconductor unique properties
1. Current conduction due to electrons and holes
(in metals – only electrons)
2. Conductivity depends on temperature,
stong dependence for intrinsic (undoped) semiconductors
3. Semiconductors can be doped to change the carrier
concentration and thus conductivity in a wide range
and also to make n-type and p-type material
This opens possibility to create p-n junction and related devices
Si, Ge
GaAs, InP,
GaN, SiC
Atom - electronic structure
metal
1 valence electron
ionic bond
Copper, Cu
conductors
Source: D.Bell, Fundamentals of Electric Circuits, Oxford Univ. Press
Atom - electronic structure
semiconductor
Silicon , Si
Germanium, Ge
Carbon, C
4 valence electrons
covalent bond
4 empty states
Source: D.Bell, Fundamentals of Electric Circuits, Oxford Univ. Press
Atoms - bonds - crystal lattice
Crystal lattice
covalent bond
2 electrons
shared by 2 atoms
broken bond
1 electron only
4 valence electrons
Source: B.G.Streetman, Solid State Electronic Devices, Prentice-Hall,
Atoms - crystal lattice – electronic structure
Energy Bands:
Conduction
Forbidden - Energy gap
Valence
4 valence
electorons
Source: R.F. Pierret, Semiconductor Device Fundamentals, Addison-Wesley Publishing Comp.
Atoms - crystal lattice – electronic structure
Energy Band Model of the crystal lattice
at absolute temperature T=0K:
Partially filled
at T>0K
Ec - Conduction band
Ec
Eg - Energy gap,
Ev
Ev - Valence band
Partially empty
at T>0K
Eg ≥ 4 eV
Eg ≤ 4 eV
Eg ≤ 0.2 (0) eV
Source: R.F. Pierret, Semiconductor Device Fundamentals, Addison-Wesley Publishing Comp.
Atoms - crystal lattice – electronic structure
Energy Band Model of the semiconductor heterostructure:
Different values of the energy gap, Eg
Energy gap values:
Ge
0.7 eV
Si
1.1 eV
GaAs 1.4 eV
GaN
3.4 eV
SiC
3.3 eV
1 eV = 1.6 10-19 J
1 eV = 1q x 1V
(energy = charge x voltage)
Source: B.G.Streetman, Solid State Electronic Devices, Prentice-Hall.
Atoms - crystal lattice – charge carriers
Creation of the electron–hole pairs (charge carriers)
if excess energy is supplied to the lattice.
- increase of temperature, T – thermal generation
- illumination, photon energy hv≥ν Eg – photogeneration
Generation:
free electron
n = p = ni
Recombination
of the electron – hole pair
photon
free hole
Source: B.G.Streetman, Solid State Electronic Devices, Prentice-Hall,.
Charge carriers in intrinsic semiconductors
Increase of temperature – thermal generation
0.7eV
1.1eV
p – hole (positive charge, +q) concentration
n - electron (negative charge, -q) concentration,
ni – intrinsic carrier concentration [1/cm3]
q=1.6 10-19 C - elementary charge
k – Boltzman constant
intrinsic - undoped semiconductor
Generation of the electron – hole pairs
n = p = ni - constant at given T
1.4eV
kT = 26meV at T=300K
C - constant
Source: B.G.Streetman, Solid State Electronic Devices, Prentice-Hall,
Doping of semiconductors
Ionization of acceptors
Na – concentration of acceptors [1/cm-3]
thermal generation
Electrons jump to acceptor level leaving free holes
in the valence band
Acceptor atom (III) - 3 valence electrons
if ionized has -q charge
Donor atom (V) - 5 valence electrons
if ionized has +q charge
n p= ni 2
x
Resulted carrier concentration:
Holes: p = Na
p-type semiconductor
Electrons:
Mass action law
n= ni2/p = ni2 / Na
n< p
ni – intrinsic carrier concentration [1/cm3]
Source: B.G.Streetman, Solid State Electronic Devices, Prentice-Hall,.
Doping of semiconductors
Ionization of donors
Nd – concentration of donors [1/cm-3]
Conduction band
free electrons n = Nd
free electron
Electrons bonded with donor atoms
ni
thermal generation of carriers
free hole
Valence band
Resulted carrier concentration:
Electrons: n = Nd,
n-type semiconductor
Holes:
p= ni 2 /n = ni 2 / Nd
p<n
ni – intrinsic carrier concentration [1/cm3]
Source: R.F. B.G.Streetman, Solid State Electronic Devices, Prentice-Hall,
Energy band models
Fermi level position denotes type of conductivity of semiconductor
and is closely related to the carrier concentrations (n, p)
ni
Ei = EFi - denotes intrinsic semiconductor Fermi level - in the middle of the energy gap
Source: R.F. Pierret, Semiconductor Device Fundamentals, Addison-Wesley Publishing Comp.
Energy band models
Fermi level position denotes the probability of that energy level
occupancy by an electron equals 1/2 at any temperature T.
holes
Ev
Ec
electrons
Eg
EF– Fermi level in the middle of the energy gap – the case for intrinsic semiconductor
Source: B.G.Streetman, Solid State Electronic Devices, Prentice-Hall
Carriers in doped (extrinsic) semiconductors
Temperature dependence of carrier concentration for n-type semiconductor
Nd – constant concentration of donors
Conductivity of doped
semiconductor :
Operational temperature range
σ=q n un = q Nd un
n= Nd
donor atoms
thermal generation
un – electron mobility
Conductivity of intrinsic
semiconductor :
σ=q ni( un + up )
un – electron mobility
up – hole mobility
ni – intrinsic carrier concentration
Source: B.G.Streetman, Solid State Electronic Devices, Prentice-Hall,
Intrinsic semiconductor resistivity and application
in temperature sensors - thermistors
Temperature dependence of conductivity
for intrinsic semiconductor
σ=q ni( un + up )
NTC
T  : Δni generated
Δσ=q Δni ( un + up )
ΔG~ Δσ
G  R
NTC thermistor : T  R
NTC - negative temperature
coefficient (TC < 0)
typical value:
Operational temperature range
RTD – Resistance Temperature Detectors
Metallic resistors – temperature sensors
Linear temperature dependence
of specific resistance of metal (especially Pt)
i.e. linear sensor
positive and constant temperature coefficient
of resistance (TC > 0 ; TC=const.)
Different types
of Pt100 sensors
all metals: if T  R↑
Pt100 temp. sensor:
R=100  at T=0˚C
and
TC = 0.00385/ ˚C or TC = 0.385 % / ˚C
R =0.385  / ˚C
R= 138.5  at 100 ˚C
Operational temperature range -200 ÷ +800 ˚C
Carrier properties in semiconductors
Drift current (flow of carriers in the electric field)
E= V/l
S
Scattering on the lattice atoms
Drift velocity
l
V
I= f (V) – current voltage dependence
R=V/I - resistance
G=I/V – conductance
G= σ (S /l)
σ – conductivity - material property
ρ =1/σ - resistivity
R = ρ (l/S)
Conductivity of intrinsic
semiconductor :
σ=q ni( un + up )
un – electron mobility
up – hole mobility
Source: R.F. Pierret, Semiconductor Device Fundamentals, Addison-Wesley Publishing Comp.
Carrier properties in semiconductors
Conductivity of the intrinsic
semiconductor :
Carrier mobility
σ=q ni(mn + mp )
mn – electron mobility
mp – hole mobility
electrons
mn  mp
holes
un = vd/E
carrier mobility
is constant
Conductivity
strongly depends on temperature
therefore
Resistivity: ρ =1/σ
strongly depends on temperature
Source: B.G.Streetman, Solid State Electronic Devices, Prentice-Hall,
Carrier properties in semiconductors
Diffusion current - flow of carriers due to their non-uniform
distribution (concentration gradient)
- no applied voltage (electric field) needed
holes
electrons
Source: R.F. Pierret, Semiconductor Device Fundamentals, Addison-Wesley Publishing Comp.
Photon absorption in semiconductors
Photoexcitation – generation of carriers (el.-hole pairs)
under the condition: hv=Eg (hv – photon energy)
This is material absorption edge definition: λ[um]=1.24/Eg [eV]
PbSe
MID-IR PHOTORESISTOR
PbSe
ROITHNER LASERTECHNIK GmbH
Source: B.G.Streetman, Solid State Electronic Devices, Prentice-Hall,
Photoexcitation of semiconductors - photoresistors
Photoexcitation – generation of carriers
Drft current (if bias voltage applied) and recombination
of carriers follows the light pulses
semiconductor
Source: R.F. Pierret, Semiconductor Device Fundamentals, Addison-Wesley Publishing Comp.
Light sensor - photoresistor in a circuit
Photoresistor
Light sensitive resistor
σ=q ni( un + up )
light ON: Δni generated
Δσ=q Δni( un + up )
ΔG~ Δσ
G  R
APPLICATION NOTE 3444
Emergency light switch
Light gets on when the power is out
Copyright © by Maxim Integrated Products
Additional legal notices: www.maxim-ic.com/legal
.
Carrier properties in semiconductors
- influence of magnetic field
The Hall effect - magnetic field deflects (the Lorentz force)
movement of charged particles (electrons and holes in semiconductors)
Hall effect sensors
Output signal:
VAB = the Hall voltage
VAB
VAB
VAB
www.bcdsemi.com.
Source: R.F. Pierret, Semiconductor Device Fundamentals, Addison-Wesley Publishing Comp.
Magnetic field sensor - hallotron
Hallotrons
Integrated Hall effect sensors
Parameter, Symbol, Conditions, [Min, Typ, Max]
Supply Current, ICC = 3.5 - 4.5 mA
Tachometer
Quiescent Output Voltage, VNULL, @ B=0 Gs:
2.25, 2.5, 2.75 V
Output Voltage Sensitivity, B=0 Gs to ±1000 Gs:
1.1, 1.6, 2.1 mV/Gs
The Earth magnetic field ~50Gs
Source: www.bcdsemi.com
.
Resistive strain gauge
Strain gauge – a thin semiconductor (or metal) resistor – attached to the tested
mechanical element : beam, rod, shaft, cantilever, propeller, wing, etc.
Resistance, R depends on the resistor dimensions: length – l , cross section area – S
and semiconductor resistivity, ρ.
R = ρ (l/S)
Semiconductor resistor resistance changes due to the stress (strain) by:
- change of the geometrical dimensions, l+Δl
- change of the carrier mobility value, μ
This induces change of conductivity Δσ=q(nΔμn + pΔμp )
ρ=1/ σ
Resistor bridge
sensor
Δρ=1/ Δσ
Micron Instruments, CA,. USA