A SURVEY OF SEMICONDUCTOR DEVICES
A SURVEY OF SEMICONDUCTOR DEVICES
A SURVEY OF SEMICONDUCTOR DEVICES
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IEEE EDS Distinguished Lecture<br />
A <strong>SURVEY</strong> <strong>OF</strong> <strong>SEMICONDUCTOR</strong> <strong>DEVICES</strong><br />
N.C. A&T State University<br />
Greensboro, NC<br />
Jan. 28, 2011<br />
Kwok Ng<br />
Sr. Director<br />
Semiconductor Research Corp (SRC)<br />
Research Triangle Park, N. Carolina<br />
1/39 K. Ng
K. K. Ng, Complete Guide to Semiconductor Devices, 2nd Ed.,<br />
Wiley/IEEE Press, 2002.
BASIC ELECTRONIC COMPONENTS<br />
L ---------------- DIFFERENTIATOR V L , STABILIZE I<br />
dI<br />
= ---dt<br />
1<br />
C ---------------- INTEGRATOR V = --- I dt,<br />
STABILIZE V<br />
C∫<br />
R ---------------- DEVELOP VOLTAGE DROP, RESISTS I<br />
DIODE --------- RECTIFIER, NON-LINEAR, LOGIC (LIMITED)<br />
TRANSISTOR----- LOGIC, AMPLIFICATION<br />
3/39 K. Ng
WHY IS TRANSISTOR THAT USEFUL?<br />
1. TRANSFER-RESISTOR => AMPLIFICATION<br />
(DIODE CAN’T)<br />
2. 3-TERMINAL => INPUT/OUTPUT ISOLATION<br />
(DIODE CAN’T)<br />
3. INVERTER (MUST FOR DIGITAL CIRCUITS, DIODE CAN’T)<br />
IN OUT<br />
IN OUT<br />
4/39 K. Ng
HOW VACUUM TUBES WORK<br />
HEATER<br />
I<br />
ELECTRONS<br />
CATHODE<br />
SCL CURRENT<br />
ANODE<br />
VACUUM<br />
GLASS TUBE<br />
T2 > T1<br />
T1<br />
TEMP.-LIMITED<br />
CURRENT<br />
V<br />
V<br />
5/39 K. Ng
IP<br />
PLATE<br />
CATHODE<br />
T2 > T1<br />
T 1<br />
V P<br />
TEMP-LIMITED<br />
CURRENT<br />
SCL CURRENT<br />
V P<br />
VG<br />
GRID<br />
IP VG = 0<br />
VACUUM TUBES<br />
DIODE TUBE TRIODE TUBE TETRODE TUBE PENTODE TUBE<br />
PLATE<br />
CATHODE<br />
V G < 0<br />
V P<br />
VP<br />
VG<br />
IP<br />
GRID<br />
CATHODE<br />
PLATE<br />
VG = 0<br />
V P<br />
V P<br />
SCREEN<br />
VG < 0<br />
SUPPRESSOR<br />
GRID<br />
VG<br />
IP<br />
PLATE<br />
CATHODE<br />
VG = 0<br />
VG < 0<br />
V P<br />
VP<br />
SCREEN<br />
6/39 K. Ng
HIGH POWER DISSIPATION<br />
LOW RELIABILITY<br />
LARGE SIZE<br />
After S. M. Sze<br />
PROBLEMS <strong>OF</strong> VACUUM TUBES<br />
LOW POWER DISSIPATION<br />
HIGH RELIABILITY<br />
SMALL SIZE<br />
TRANSISTOR<br />
SOLUTION<br />
7/39 K. Ng
10 18 10 16 10 14 10 12 10 10 10 8 10 6 10 4 10 2 1 10 –2 10 –4 10 –6 10 –8<br />
SULFUR<br />
DIAMOND (PURE)<br />
FUSED QUARTZ<br />
WHAT IS <strong>SEMICONDUCTOR</strong>?<br />
GLASS<br />
NICKEL OXIDE (PURE)<br />
RESISTIVITY ρ (Ω-cm)<br />
GERMANIUM (Ge)<br />
SILICON (Si)<br />
GALLIUM ARSENIDE (GaAs)<br />
GALLIUM PHOSPHIDE (GaP)<br />
CADMIUM SULFIDE (CdS)<br />
SILVER<br />
COPPER<br />
ALUMINUM<br />
PLATINUM<br />
BISMUTH<br />
10–18 10–16 10–14 10–12 10–10 10–8 10–6 10–4 10–2 1 102 104 106 108<br />
CONDUCTIVITY σ (S/cm)<br />
INSULATOR <strong>SEMICONDUCTOR</strong><br />
0.1 eV < Eg < 4 eV<br />
METAL<br />
8/39 K. Ng
WHY IS <strong>SEMICONDUCTOR</strong> USEFUL?<br />
SOLID STATE, SINGLE CRYSTAL (RELIABILITY, DENSITY)<br />
GOOD CONDUCTIVITY (VARIABLE)<br />
DOPING CAN BE DEPLETED => SPACE CHARGE => POTENTIAL BARRIER<br />
(NOT IN METAL)<br />
FIELD CAN PENETRATE (NOT IN METAL)<br />
ENERGY GAP => PHOTONIC <strong>DEVICES</strong> (NOT IN METAL)<br />
ELIMINATE<br />
VACUUM TUBE<br />
ELIMINATE<br />
INSULATOR<br />
ELIMINATE<br />
METAL<br />
9/39 K. Ng
p-n JUNCTION FIELD-EFFECT TRANSISTOR<br />
LED LASER SOLAR<br />
CELL TUNNEL p-n<br />
DIODE DIODE MOSFET MESFET MODFET<br />
ZENER<br />
DIODE<br />
<strong>SEMICONDUCTOR</strong> DEVICE HIERARCHY: device vs. variation<br />
VARACTOR TFT DMOS<br />
≈ 77<br />
MAJOR<br />
<strong>DEVICES</strong><br />
≈ 120<br />
RELATED<br />
<strong>DEVICES</strong><br />
10/39 K. Ng
Examples:<br />
Some are device variations<br />
III-V MOSFET, CNT FET, graphene FET<br />
These are variations of channel materials for MOSFET.<br />
Examples:<br />
Some are not “Semiconductor” devices<br />
Single-electron transistor<br />
Molecular devices<br />
Spintronics<br />
Polymer devices<br />
MEMS (micro-electro-mechanical system)<br />
etc<br />
11/39 K. Ng
Device vs. Circuit<br />
Device: parts cannot be reconnected by wire<br />
Bipolar transistor<br />
MOSFET<br />
Device Circuit<br />
n<br />
p<br />
n<br />
n<br />
p<br />
n p<br />
n + p n<br />
p<br />
+ n + n +<br />
CMOS inverter<br />
p-MOS<br />
n-MOS<br />
CMOS detector (no gain as<br />
phototransistor)<br />
Detector MOSFET<br />
12/39 K. Ng
“All it Takes is Concentration”
<strong>SEMICONDUCTOR</strong>-DEVICE CLASSIFICATION<br />
1.Diodes Rectifiers<br />
Neg Resist N-shape<br />
S-shape<br />
Transit-Time<br />
2.Resistive/Capacitive Devices<br />
3.Transistors FET<br />
PET<br />
4.Nonvolatile Memories<br />
5.Thyristors and Power<br />
6.Photonics Light Sources<br />
Photodetectors<br />
Bistable Opt Dev<br />
Others<br />
7.Sensors<br />
14/39 K. Ng
American Heritage<br />
WHAT IS DIODE?<br />
“An electronic device that restricts current flow chiefly to one direction”<br />
Webster’s<br />
“A rectifier that consists of a semiconducting crystal with two terminals and that is<br />
analogous in use to an electron tube diode.”<br />
Inconsistent devices:<br />
I<br />
New IEEE Standard Dictionary of Electrical and Electronics Terms<br />
V f<br />
TUNNEL DIODE<br />
“A semiconductor device having two terminals and exhibiting a nonlinear voltagecurrent<br />
characteristics”<br />
I<br />
GUNN DIODE<br />
V<br />
15/39 K. Ng
1.Diodes Rectifiers<br />
Neg Resist N-shape<br />
S-shape<br />
Transit-Time<br />
2.Resistive/Capacitive Devices<br />
3.Transistors FET<br />
PET<br />
4.Nonvolatile Memories<br />
5.Thyristors and Power<br />
6.Photonics Light Sources<br />
Photodetectors<br />
Bistable Opt Dev<br />
Others<br />
7.Sensors<br />
1. p-n Diode<br />
2. Schottky-Barrier<br />
Diode<br />
3. Planar-Doped-<br />
Barrier Diode<br />
δ-doped-,<br />
pulse-doped-,<br />
triangularbarrier<br />
4. Isotype<br />
Heterojunction<br />
5. p-i-n Diode<br />
p<br />
n<br />
n<br />
RF R<br />
VBD<br />
16/39 K. Ng<br />
I<br />
DC I<br />
Vf
1.Diodes Rectifiers<br />
Neg Resist N-shape<br />
S-shape<br />
Transit-Time<br />
2.Resistive/Capacitive Devices<br />
3.Transistors FET<br />
PET<br />
4.Nonvolatile Memories<br />
5.Thyristors and Power<br />
6.Photonics Light Sources<br />
Photodetectors<br />
Bistable Opt Dev<br />
Others<br />
7.Sensors<br />
1. Tunnel Diode<br />
2. Transferred-<br />
Electron Device,<br />
Gunn diode<br />
3. Resonant-<br />
Tunneling Diode<br />
4. Resonant-<br />
Interband<br />
Tunneling Diode<br />
5. Real-Space-<br />
Transfer Diode<br />
6. Single-Barrier<br />
Tunnel Diode<br />
7. Single-Barrier<br />
Interband-<br />
Tunneling Diode<br />
E<br />
GaAs<br />
E EC<br />
EV<br />
k<br />
AlGaAs<br />
I<br />
dI/dV =<br />
NEGATIVE<br />
V f<br />
17/39 K. Ng
1.Diodes Rectifiers<br />
Neg Resist N-shape<br />
S-shape<br />
Transit-Time<br />
2.Resistive/Capacitive Devices<br />
3.Transistors FET<br />
PET<br />
4.Nonvolatile Memories<br />
5.Thyristors and Power<br />
6.Photonics Light Sources<br />
Photodetectors<br />
Bistable Opt Dev<br />
Others<br />
7.Sensors<br />
1. MIS Switch (MISS)<br />
2. Planar-Doped-<br />
Barrier Switch<br />
3. Amorphous<br />
Threshold Switch<br />
Ovonic<br />
threshold switch<br />
4. Heterostructure<br />
Hot-Electron Diode<br />
n<br />
p<br />
I<br />
V<br />
18/39 K. Ng
1.Diodes Rectifiers<br />
Neg Resist N-shape<br />
S-shape<br />
Transit-Time<br />
2.Resistive/Capacitive Devices<br />
3.Transistors FET<br />
PET<br />
4.Nonvolatile Memories<br />
5.Thyristors and Power<br />
6.Photonics Light Sources<br />
Photodetectors<br />
Bistable Opt Dev<br />
Others<br />
7.Sensors<br />
1. IMPATT Diode<br />
Read diode<br />
2. BARITT Diode<br />
Punchthrough<br />
diode<br />
p+ n i n+<br />
AVA<br />
n<br />
DRIFT<br />
p<br />
i·v = NEGATIVE<br />
V<br />
I<br />
19/39 K. Ng<br />
t<br />
t
1.Diodes Rectifiers<br />
Neg Resist N-shape<br />
S-shape<br />
Transit-Time<br />
2.Resistive/Capacitive Devices<br />
3.Transistors FET<br />
PET<br />
4.Nonvolatile Memories<br />
5.Thyristors and Power<br />
6.Photonics Light Sources<br />
Photodetectors<br />
Bistable Opt Dev<br />
Others<br />
7.Sensors<br />
1. Resistor<br />
2. MOS Capacitor<br />
3. CCD<br />
Si<br />
C<br />
I<br />
V<br />
LOW F<br />
HI F<br />
VG<br />
OUT<br />
20/39 K. Ng
S<br />
UNIPOLAR VS. BIPOLAR <strong>DEVICES</strong><br />
3-TERMINAL MOSFET<br />
JFET<br />
S G D<br />
n + n n +<br />
p +<br />
ENHANCEMENT JFET<br />
–Jn<br />
n<br />
“UNIPOLAR” “BIPOLAR”<br />
Jp J p<br />
p<br />
BIPOLAR<br />
(Junction trans)<br />
2-TERMINAL SCHOTTKY p-n JUNCTION<br />
G<br />
D<br />
n + p n +<br />
MOSFET<br />
E B C<br />
n+ p n+<br />
BIPOLAR TRANS<br />
(hole current is junk current)<br />
(Enh. JFET has forward-bias current)<br />
J n/J p = 10 3–10 4 J n/J p ≈ N D/N A ≈ 10 20/10 16 ≈ 10 4<br />
–J n<br />
SCHOTTKY BARRIER p-n JUNCTION<br />
n +<br />
21/39 K. Ng
(TRANSFER-RESISTOR, EQUIVALENT TO TRIODE)<br />
FIELD-EFFECT TRANSISTOR POTENTIAL-EFFECT TRANSISTOR<br />
(FET) (PET)<br />
CONTROL (GATE) CONTROL (BASE)<br />
CAPACITOR<br />
SOURCE DRAIN<br />
TRANSISTOR<br />
EMITTER COLLECTOR<br />
CHANNEL CHANNEL<br />
22/39 K. Ng
1.Diodes Rectifiers<br />
Neg Resist N-shape<br />
S-shape<br />
Transit-Time<br />
2.Resistive/Capacitive Devices<br />
3.Transistors FET<br />
PET<br />
4.Nonvolatile Memories<br />
5.Thyristors and Power<br />
6.Photonics Light Sources<br />
Photodetectors<br />
Bistable Opt Dev<br />
Others<br />
7.Sensors<br />
23/39 K. Ng<br />
1. MOSFET<br />
IGFET<br />
2. Junction FET<br />
(JFET)<br />
3. MESFET<br />
4. MODFET<br />
HEMT,<br />
TEGFET, SDHT<br />
5. Permeable-Base<br />
Trans<br />
6. Static-Induction<br />
Trans (SIT)<br />
Analog Trans,<br />
multi-chan FET<br />
7. Real-Space-<br />
Transfer Trans,<br />
NERFET, CHINT<br />
8. Planar-Doped FET<br />
9. Surface-Tunnel<br />
Trans<br />
10. Lateral Resonant-<br />
Tunneling FET<br />
11. Stark-Effect Trans<br />
12. Velocity-<br />
Modulation Trans<br />
2<br />
4<br />
S<br />
n+<br />
p<br />
n +<br />
S G D n+<br />
n + p+<br />
n<br />
p+<br />
S G D<br />
n<br />
n + n +<br />
SEMI-IN GaAs<br />
G<br />
n-AlGaAs<br />
D<br />
n+ n+<br />
2-D GAS i-GaAs<br />
SEMI-IN GaAs<br />
5<br />
6<br />
1<br />
3<br />
n<br />
n<br />
p +-G<br />
n+<br />
n +<br />
n +<br />
n+<br />
S<br />
n<br />
D<br />
7<br />
9<br />
10<br />
11<br />
8<br />
S<br />
G<br />
i<br />
i<br />
D<br />
n+ n+<br />
GATES<br />
S D<br />
12<br />
S i-GaAs<br />
n+<br />
i-AlGaAs<br />
n+-GaAs<br />
n +<br />
E C<br />
n-Si<br />
D<br />
n+<br />
C<br />
p +<br />
G<br />
S G1 D<br />
n + n +<br />
Ch-1<br />
Ch-2<br />
SEMI-IN GaAs
1.Diodes Rectifiers<br />
Neg Resist N-shape<br />
S-shape<br />
Transit-Time<br />
2.Resistive/Capacitive Devices<br />
3.Transistors FET<br />
PET<br />
4.Nonvolatile Memories<br />
5.Thyristors and Power<br />
6.Photonics Light Sources<br />
Photodetectors<br />
Bistable Opt Dev<br />
Others<br />
7.Sensors<br />
24/39 K. Ng<br />
1. Bipolar Transistor<br />
Junction transistor<br />
2. Tunneling HE Transfer<br />
Amp (THETA),<br />
MOMOM<br />
3. Metal-Base Transistor<br />
4. Bipolar Inv-Ch FET<br />
(BICFET)<br />
5. Tunnel-Emitter Tran<br />
Inver-base bipolar tran<br />
6. Planar-Doped-Barrier<br />
Transistor<br />
7. Heterojunction Hot-<br />
Electron Tran<br />
8. Induced-Base<br />
Transistor<br />
9. Resonant-Tunneling<br />
Bipolar Transistor<br />
10. Resonant-Tunneling<br />
Hot-Electron Transistor<br />
11. Quantum-Well-Base<br />
Resonant-Tunnel. Tran<br />
12. Spin-Valve Transistor<br />
4<br />
n<br />
1<br />
n+<br />
E<br />
2<br />
5<br />
6<br />
3<br />
n+<br />
E<br />
n<br />
B<br />
p<br />
n+<br />
B<br />
B<br />
n +<br />
B<br />
C<br />
n+<br />
n<br />
n<br />
C<br />
n+<br />
7<br />
n<br />
E<br />
8<br />
n<br />
9<br />
n<br />
10<br />
12<br />
n<br />
11<br />
E<br />
n<br />
B<br />
p<br />
B<br />
n<br />
C<br />
C<br />
n<br />
n<br />
n<br />
n
1.Diodes Rectifiers<br />
Neg Resist N-shape<br />
S-shape<br />
Transit-Time<br />
2.Resistive/Capacitive Devices<br />
3.Transistors FET<br />
PET<br />
4.Nonvolatile Memories<br />
5.Thyristors and Power<br />
6.Photonics Light Sources<br />
Photodetectors<br />
Bistable Opt Dev<br />
Others<br />
7.Sensors<br />
1. FAMOS<br />
Transistor<br />
2. SONOS<br />
Transistor<br />
3. PCRAM<br />
4. FeRAM<br />
5. MRAM<br />
G<br />
n<br />
p-Si<br />
+ S D<br />
n+<br />
S<br />
p+<br />
G<br />
SiN<br />
n-Si<br />
D<br />
p +<br />
25/39 K. Ng
1.Diodes Rectifiers<br />
Neg Resist N-shape<br />
S-shape<br />
Transit-Time<br />
2.Resistive/Capacitive Devices<br />
3.Transistors FET<br />
PET<br />
4.Nonvolatile Memories<br />
5.Thyristors and Power<br />
6.Photonics Light Sources<br />
Photodetectors<br />
Bistable Opt Dev<br />
Others<br />
7.Sensors<br />
1. SCR,<br />
Thyristor<br />
2. Insulated-Gate Bipolar<br />
Transistor,<br />
Conductivity-<br />
Modulated FET<br />
(COMFET)<br />
3. Unijunction Transistor,<br />
Filamentary<br />
Transistor<br />
4. Static-Induction<br />
Thyristor<br />
C<br />
n<br />
p<br />
n<br />
p<br />
n<br />
p<br />
G<br />
VE<br />
A<br />
C<br />
G<br />
A<br />
n+<br />
p p+<br />
IE<br />
p +<br />
n+<br />
n –<br />
p +<br />
n–<br />
p<br />
B-2<br />
p +<br />
n<br />
B-1<br />
p+<br />
VBB<br />
I A<br />
IA<br />
I E VBB<br />
= 0<br />
V AK<br />
IA V G<br />
V AK<br />
VBB > 0<br />
VG<br />
V AK<br />
VE<br />
26/39 K. Ng
1.Diodes Rectifiers<br />
Neg Resist N-shape<br />
S-shape<br />
Transit-Time<br />
2.Resistive/Capacitive Devices<br />
3.Transistors FET<br />
PET<br />
4.Nonvolatile Memories<br />
5.Thyristors and Power<br />
6.Photonics Light Sources<br />
Photodetectors<br />
Bistable Opt Dev<br />
Others<br />
7.Sensors<br />
1. LED<br />
2. Injection Laser<br />
Junction laser<br />
p<br />
n<br />
n+<br />
n +<br />
p+<br />
N 2<br />
N1<br />
E C<br />
EV<br />
IN OUT<br />
27/39 K. Ng
1.Diodes Rectifiers<br />
Neg Resist N-shape<br />
S-shape<br />
Transit-Time<br />
2.Resistive/Capacitive Devices<br />
3.Transistors FET<br />
PET<br />
4.Nonvolatile Memories<br />
5.Thyristors and Power<br />
6.Photonics Light Sources<br />
Photodetectors<br />
Bistable Opt Dev<br />
Others<br />
7.Sensors<br />
28/39 K. Ng<br />
1. Photoconductor<br />
2. p-i-n Photodiode<br />
3. Schottky-Barrier<br />
Photodiode<br />
4. Charge-Coupled<br />
Image Sensor<br />
5. Avalanche Photodiode<br />
(APD)<br />
6. Phototransistor<br />
7. Metal-Semiconductor-<br />
Metal Photodetector<br />
8. Quantum-Well IR<br />
Photodetector (QWIP)<br />
9. Quantum-Dot IR<br />
Photodetector (QDIP)<br />
10. Block-Impurity-Band<br />
Photodetector<br />
11. Negative-Electron-<br />
Affinity (NEA)<br />
Photocathode<br />
12. Photon-Drag Detector<br />
3<br />
1<br />
p+<br />
2<br />
4<br />
5<br />
E<br />
6<br />
I<br />
i<br />
B<br />
LIGHT<br />
DARK<br />
V<br />
n +<br />
C<br />
10<br />
11<br />
12<br />
8<br />
7<br />
9<br />
n-InGaAs<br />
SEMI-IN InP<br />
+ + + + + +<br />
DONORS<br />
ACCEPTORS<br />
V<br />
Evac<br />
qχ<br />
SEMICOND
1.Diodes Rectifiers<br />
Neg Resist N-shape<br />
S-shape<br />
Transit-Time<br />
2.Resistive/Capacitive Devices<br />
3.Transistors FET<br />
PET<br />
4.Nonvolatile Memories<br />
5.Thyristors and Power<br />
6.Photonics Light Sources<br />
Photodetectors<br />
Bistable Opt Dev<br />
Others<br />
7.Sensors<br />
1. Self-Electrooptic-<br />
Effect Device (SEED)<br />
2. Bistable Etalon<br />
Fabry-Perot<br />
Resonator<br />
p +<br />
IN OUT<br />
MQW<br />
Iin<br />
n+<br />
nr = f(I)<br />
I = f(nrL)<br />
Iout<br />
LIGHT OUTPUT<br />
LIGHT OUT<br />
α ∝ 1/E<br />
29/39 K. Ng<br />
LIGHT INPUT<br />
LIGHT IN
1.Diodes Rectifiers<br />
Neg Resist N-shape<br />
S-shape<br />
Transit-Time<br />
2.Resistive/Capacitive Devices<br />
3.Transistors FET<br />
PET<br />
4.Nonvolatile Memories<br />
5.Thyristors and Power<br />
6.Photonics Light Sources<br />
Photodetectors<br />
Bistable Opt Dev<br />
Others<br />
7.Sensors<br />
1. Solar Cell<br />
2. Electroabsorption<br />
Modulator<br />
p-n JUNCTION<br />
SCHOTTKY BARRIER<br />
IN OUT<br />
MQW<br />
n+<br />
TRANS<br />
J<br />
30/39 K. Ng<br />
DARK<br />
LIGHT<br />
V<br />
V
1.Diodes Rectifiers<br />
Neg Resist N-shape<br />
S-shape<br />
Transit-Time<br />
2.Resistive/Capacitive Devices<br />
3.Transistors FET<br />
PET<br />
4.Nonvolatile Memories<br />
5.Thyristors and Power<br />
6.Photonics Light Sources<br />
Photodetectors<br />
Bistable Opt Dev<br />
Others<br />
7.Sensors<br />
1. Thermistor<br />
2. Hall Plate, Hall<br />
Generator<br />
3. Strain Gauge<br />
4. Interdigital<br />
Transducer, SAW<br />
Transducer<br />
5. Ion-Sensitive FET,<br />
CHEMFET<br />
Vin<br />
R<br />
B<br />
V<br />
T<br />
STRAIN GAUGE<br />
V G<br />
n+ n +<br />
p-Si<br />
Ix<br />
SAW<br />
Vout<br />
31/39 K. Ng
MARKET SHARE (%)<br />
100<br />
80<br />
60<br />
40<br />
20<br />
WORLD-WIDE IC MARKET (1980-2000)<br />
BIPOLAR<br />
MOSFET(Si)<br />
III-V<br />
0<br />
1980 1985 1990 1995 2000<br />
YEAR<br />
After S. M. Sze<br />
4%<br />
8%<br />
88%<br />
32/39 K. Ng
WHY Si (OVER OTHER <strong>SEMICONDUCTOR</strong>S)?<br />
NEAR-IDEAL <strong>SEMICONDUCTOR</strong>/OXIDE INTERFACE!<br />
BETTER CRYSTAL QUALITY THAN COMPOUND <strong>SEMICONDUCTOR</strong>S<br />
DISADVANTAGES<br />
INDIRECT ENERGY GAP => NO LIGHT SOURCE<br />
LESS FREEDOM IN HETEROEPITAXY<br />
SUBSTRATE NOT SEMI-INSULATING<br />
MOBILITY NOT AS HIGH<br />
33/39 K. Ng
10<br />
Sales ($Billion) 100<br />
DRAM<br />
Technology driver<br />
NVM (flash)<br />
SRAM<br />
1<br />
1990 1995 2000<br />
Year<br />
2005 2010<br />
Market size (arbitrary unit)<br />
Bipolar<br />
All semiconductor<br />
DRAM/CPU<br />
Nonvolatile memory<br />
1950 1970 1990 2010<br />
Year<br />
Floating-gate or SONOS type of MOSFETs will be dominant<br />
34/39 K. Ng
MAJOR DEVICE & CIRCUIT MILESTONES<br />
VACUUM TUBES (1904)<br />
BIPOLAR TRANSISTOR (1947)<br />
(1958) INTEG. CIRCUIT<br />
MOSFET (1960)<br />
(1963) CMOS<br />
(1968) DRAM<br />
(1971) MICROPRO<br />
JFET (1952)<br />
MESFET (1966)<br />
FAMOS (1967)<br />
MODFET (1980)<br />
(1826) RESISTOR<br />
(1938) SCHOTTKY BARRIER<br />
(1949) p-n JUNCTION<br />
(1951) LED<br />
(1956) SCR<br />
(1958) TUNNEL DIODE<br />
(1962) LASER<br />
(1963) GUNN DIODE<br />
(1965) IMPATT DIODE<br />
(1970) CCD<br />
(1974) RESONANT-TUNNELING DIODE<br />
35/39 K. Ng
METAL-<br />
<strong>SEMICONDUCTOR</strong><br />
n p n<br />
DEVICE BUILDING BLOCKS–5 INTERFACES<br />
METALLIZATION<br />
BIPOLAR<br />
n +<br />
IMPLANTATION/<br />
DIFFUSION<br />
E C<br />
EF<br />
E V<br />
DOPING HETEROJUNCTION<br />
POLY<br />
p-Si<br />
MOSFET<br />
n +<br />
EPITAXY<br />
OXIDATION<br />
<strong>SEMICONDUCTOR</strong>-<br />
INSULATOR<br />
METALLIZATION/CVD<br />
INSULATOR-<br />
METAL/POLY<br />
36/39 K. Ng
CURRENT-CONDUCTION MECHANISMS <strong>OF</strong><br />
<strong>SEMICONDUCTOR</strong> <strong>DEVICES</strong>.<br />
Mechanisms Examples<br />
Drift Resistor, most FETs<br />
Diffusion p-n junction, bipolar transistor<br />
Thermionic emission Schottky barrier, PDB diode<br />
Tunneling Tunnel diode, ohmic contact<br />
Recombination LED, p-i-n diode<br />
Generation Solar cell, photodetectors<br />
Avalanche IMPATT diode, Zener diode<br />
37/39 K. Ng
1. Fast intrinsic response?<br />
2. Fast circuit?<br />
V G<br />
“High-speed” device<br />
Parameters Considerations Speed fig-of-merit of FET<br />
Transit time Intrinsic, no capacitance gm/CG<br />
S-para. meas. (f T) No output capacitance, no runner g m/(C G+C ip)<br />
(fmax) Optimized load, no runner<br />
Ring oscillator Fan-out = 1, short runner gm/(CG+Cip+Cout)<br />
Real circuit Mult fan-outs, long runner, load capacitance g m/(C G+C ip+C out+C run+C lo)<br />
High intrinsic speed not sufficient (although necessary)!<br />
Critical parameters: gm, CG, Cdrain, etc.<br />
I<br />
Q<br />
C<br />
VL<br />
I I I<br />
Speed ≈ --- ≈ ---------- ≈ ----------- ≈<br />
Q CV<br />
L<br />
CV<br />
G<br />
g<br />
m<br />
------<br />
C<br />
38/39 K. Ng
CONCLUDING REMARKS<br />
• Identified ~ 77 major devices, ~ 120 variations.<br />
• All semiconductor devices are based on 5 building blocks.<br />
• Few devices dominate > 95% of market.<br />
• Si continues to dominate (~ 97%).<br />
• MOSET continues to be the workhorse of industry (~ 80%).<br />
• Most-common MOSFETs are in the form of floating-gate and charge-trapping<br />
(SONOS) nonvolatile memories (flash), not as logic devices.<br />
• Some confusion in device names, e.g. diode, switch, bipolar/unipolar, etc. Duplication<br />
of names: e.g. MODFET/HEMT/TEGFET/SDHT.<br />
• What has happened in the last 10 years:<br />
1. Many newer structures are old devices (e.g. carbon nanotube, nanowire, graphene<br />
FETs are MOSFETs with new channel materials).<br />
2. Many new devices are not necessary semiconductor devices (e.g. single-electron transsitor,<br />
spin devices, MIM switch...).<br />
3. Some are still in proposal stage (e.g. spin-based devices using spin rather than V or I<br />
as signal).<br />
39/39 K. Ng