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Display and OLED Market OLED on glass only ~US$ 0.5B in 04, vs. FPD (TFT/LCD) ~US$40 B. However, OLED Market will be boosted by Flexible Display with the OTFT enabling technology to fit niche and open new market other than the rigid TFT/LCD based FPD.

Solar Energy Market Present: 740MW in 03, 1/2 nuclear plant; Solar-Cell Cell s s still <0.1% of global electrical energy 30-50% annual growth Revenue for installation (e.g., hardware) US$4.7B in 2003 Prediction: By 2030, expected 140GW, 100 nuclear plant (IEEE) Major market : ngapore (Southeast Asia), US, China, Japan,, and remote rural areas. Polymer Solar-Cell is emerging to be the cost-effective solution Now 10-20 cents/ KWH off grid, 5 cent for fossil fuel @ ~ $40/barrel

Power is the ISSUE

Table 1.1 How many element in earth (118) A portion of the periodic table showing elements used in semiconductor materials Group Period II III IV V VI 2 B Boron C Carbon N Nitrogen O Oxygen 3 Al Aluminum licon P Phosphorus S Sulfur 4 Zn Zinc Ga Gallium Ge Germanium As Arsenic Se Selenium 5 Cd Cadmium In Indium Sn Tin Sb Antimony Te Tellurium 6 Hg Mercury

Table 1.2 A partial list of semiconductor materials Elemental Semiconductors IV Compound Semiconductors licon C licon carbide Ge Germanium Ge licon germanium Binary III-V Compounds Binary II-VI Compounds AlAs Aluminum arsenide CdS Cadmium sulfide AlP Aluminum phosphide CdTe Cadmium telluride AlSb Aluminum antimonide HgS Mercury sulfide GaAs Gallium arsenide ZnS Zinc sulfide GaP Gallium phosphide ZnTe Zinc telluride GaSb InAs Gallium antimonide Indium arsenide InP Indium phosphide Ternary Compounds Quaternary Compounds Al x Ga 1-x As Aluminum gallium arsenide Al x Ga 1-x As y Sb 1-y Aluminum gallium arsenic atimonide GaAs 1-x P x Gallium arsenic phosphide Ga x In 1-x As 1-y P y Gallium indium arsenic phosphide

What is the mobility 2.2 2.0 GaP 0.15K 0.14K AlAs Direct gap indirect gap - 0.6 Bandgap energy Eg (ev) 1.8 1.6 1.4 1.2 1.0 0.8 0.6 0.4 0.2 1.5K 0.45K GaAs 8.5K 0.4K strained Ge 3.9K 1.9K InP 5.4K 0.2K InAs 26.7K 0.2K AlSb GaSb 3K 1.2K InSb e77k h0.85k - 0.7-0.8-0.9-1.0-1.2-1.5-2.0-3.0-4.0-6.0-10 Wavelength (um) 5.4 5.6 5.8 6.0 6.2 6.4 Lattice constant a 0 (Angstroms)

Bandgap energy Eg (ev) 2.4 2.2 2.0 1.8 1.6 1.4 1.2 1.0 0.8 0.6 0.4 0.2. βc. GaP -7.5mev/%Ge. GaAs... strained AlAs Ge. InP. AlSb.. InSb InAs Direct gap indirect gap - 0.6 GaSb - 0.7-0.8-0.9-1.0-1.2-1.5-2.0-3.0-4.0-6.0-10 Wavelength (um) 4.2 4.4 4.6 4.8 5.0 5.2 5.4 5.6 5.8 6.0 6.2 6.4 Lattice constant a 0 (Angstroms) λ > 10 μm, quantum cascade emitter

Why licon? Abundant, cheap licon dioxide is very stable, strong dielectric, and it is easy to grow in thermal process. Large band gap, wide operation temperature range. Ge will be exhausted in 2 decades if used in VLSI.

Introduction The advantages and disadvantages of Ge Mobility Issue Electron Hole Low Field Mobility as Compared with 2.7 X 4 X Natural Abundance Ge will be run out in 16 years. Abundance (ppm) Ge 272000 1.5 Poor Interface Properties Germanium oxide will be dissolved in water.

Amorphous Structure

Polycrystalline Structure Grain Boundary Grain

ngle Crystal Structure

FEI Titan with Cs-probe corrector Raw STEM image <110> Reflections down to 0.8 Å {400} ~ 1.36 Å {422} ~ 1.11 Å {511} ~ 1.05 Å {333} ~ 1.05 Å {440} ~ 0.96 Å {533} ~ 0.83 Å No drift, no distortions, minimal noise, no forbidden reflections {200}, {600}

Name licon Symbal Atomic number 14 Atomic weight 28.0855 Discoverer Jöns Jacob Berzelius Discovered at Sweden Discovery date 1824 Origin of name From the Latin word "silicis" meaning "flint" Bond length in single crystal 2.352 Å Density of solid 2.33 g/cm 3 Molar volume 12.06 cm 3 Velocity of sound 2200 m/sec Electrical resistivity 100,000 μω cm Reflectivity 28% Melting point 1414 C Boiling point 2900 C Source: http://www.shef.ac.uk/chemistry/web-elements/nofr-key/.html

(100) (001) a (111) (110) (010) Unit Cell of ngle Crystal licon

Crystal Orientations: <100> <100> plane z y x

Crystal Orientations: <111> z <100> plane <111> plane y x

Crystal Orientations: <110> z <110> plane y x

<100> Orientation Plane Basic lattice cell Atom

<111> Orientation Plane Basic lattice cell licon atom

<100> Wafer Etch Pits

<111> Wafer Etch Pits

Illustration of the Defects Impurity on substitutional site licon Atom licon Interstitial Impurity in Interstitial te Vacancy or Schottky Defect Frenkel Defect

Dislocation Defects

Ingot Polishing, Flat, or Notch Flat, 150 mm and smaller Notch, 200 mm and larger

Parameters of licon Wafer Wafer ze (mm) Thickness (μm) Area (cm 2 ) Weight (grams) 50.8 (2 in) 279 20.26 1.32 76.2 (3in) 381 45.61 4.05 100 525 78.65 9.67 125 625 112.72 17.87 150 675 176.72 27.82 200 725 314.16 52,98 300 775 706.21 127.62

Semiconductor Substrate and Dopants Substrate P-type Dopant N-type Dopants

Band Gap and Resistivity E g = 1.1 ev E g = 9 ev Aluminum Sodium licon licon dioxide 2.7 μω cm 4.7 μω cm ~ 10 10 μω cm > 10 20 μω cm Conductors Semiconductor Insulator

Crystal Structure of ngle Crystal licon Shared electrons -

E Intrinsic licon Conduction band E c E g E v Valence band Free electron (-) Free hole (+) N(E) : Density of States (Appendix C) p= n= E v E c ( ) f ( ) N E ( )[ 1 f ( E) ] N E E de de

N-type (Arsenic) Doped licon and Its Donor Energy Band As Conducting band, E c Extra Electron E g = 1.1 ev E d ~ 0.05 ev - Valence band, E v

P-type (Boron) Doped licon and Its Donor Energy Band B Hole Conducting band, E c E g = 1.1 ev - E a ~ 0.05 ev Electron Valence band, E v

Illustration of Hole Movement Conducting band, E c Conducting band, E c Conducting band, E c Electron E g = 1.1 ev E a ~ 0.05 ev Electron E g = 1.1 ev Electron E g = 1.1 ev Hole Valence band, E v Hole Valence band, E v Valence band, E v Hole

NMOS Device Positive charges V G = 0 V D Electron flow V G > V T > 0 V D > 0 Metal Gate O 2 n + Source p- n + Drain O 2 n + Source + + + + + + + p- Drain n + Body contact No current Negative charges

From 1960s to 1970s 1960s PMOS Diffusion Metal gate 1970s NMOS Ion implantation Polysilicon gate

1980 s Technology LCD replacing LED as indicators for electronic watches and calculators CMOS IC replacing NMOS IC for lower power consumption Minimum feature size: from 3 μm to 0.8 μm Wafer size: 100 mm (4 in) to 150 mm (6 in)

IC Design: CMOS Inverter V ss NMOS V in V out PMOS V dd (a) Poly gate/li N-channel active region N-channel Vt N-channel LDD N-channel S/D Shallow trench isolation (STI) P-channel active region P-channel Vt P-channel LDD P-channel S/D (b) P-well Metal 1 Polycide gate and local interconnection N-well Contact Metal 1, AlCu W PMD n + P-Well n + P-Epi STI P-Wafer p + p + N-Well (c)

Wafer Process Flow Materials IC Fab Metallization CMP Dielectric deposition Test Wafers Masks Thermal Processes (RTA, RTO) Implant PR strip Etch PR strip Packaging Photolithography Final Test Design