Công nghệ chế tạo vật liệu nano

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Synthesis and Fabrication

of Electronic Materials

Prof. Dr. Nguyen Van Hieu

International Training Institute for Materials Science (ITIMS)

Lab. Of Nanosensors

Lecture Content

5.1. Introduction to semiconductors

5.1.1.Essentials on semiconductors (“refreshing”)

5.1.2.History of semiconductor technology

5.2. Growth and process of semiconductor materials

5.2.1. Types of semiconductors.

5.2.2. Crystal growth and wafer fabrication

5.2.3. Physical and chemical vapor deposition (PVD&CVD).

5.3. Synthesis of one-dimensional nanostructures

5.3.1. Synthesis of carbon nanotubes.

5.3.2. Synthesis of metal oxide nanowires (NWs).

5.4. Nanostructures fabricated by physical methods

5.1. Introduction to semiconductors

5.1.1.Essentials on semiconductors

Metallic conductor:

 typically 1 or 2 freely moving electrons per atom

Semiconductor:

 typically 1 freely moving electron per 109-1017

atoms

What is the result on the properties of such a

material?

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5.1. Introduction to semiconductors

5.1.1.Essentials on semiconductors

5.1. Introduction to semiconductors

5.1.1.Essentials on semiconductors

II III IV V VI

Be B C N O

Mg Al Si P S

Zn Ga Ge As Se

Elemental semiconductors:

C, Si, Ge (all group IV)

Compound semiconductors:

III-V: GaAs, GaN…

II-VI: ZnO, ZnS,…

Group-III and group-V

atoms are “dopants”

Semiconductors in the periodic table

5.1. Introduction to semiconductors

5.1.1.Essentials on semiconductors

 Small impurities can dramatically change

conductivity:

 slight phosphorous contamination in silicon gives

many extra free electrons in the material (one per P

atom!)

 slight aluminum contamination gives many extra

holes (one per Al atom)

P Al

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5.1. Introduction to semiconductors

5.1.1.Essentials on semiconductors

- Atomic radius:

0.117nm, or

0.234nm.

-Lattice constant:

0.5nm.

-Atomic radius ~ As,

In (0.121, 0.166)

5.1. Introduction to semiconductors

5.1.1.Essentials on semiconductors

II III IV V VI

Be B C N O

Mg Al Si P S

Zn Ga Ge As Se

In

Boron most widely used

as p-type dopant;

Aluminum in old processes

(Indium (In) seldom used)

Phosphorous and arsenic

both used widely as n-type

dopant

(Antimony (Sb) seldom used)

P: higher diffusion,

better activation than As

Silicon dopants

5.1. Introduction to semiconductors

5.1.1.Essentials on semiconductors

n-type doped semiconductor

e.g. silicon with phosphorus impurity

electrons determine conductivity

p-type doped semiconductor

e.g. silicon with Al impurity

holes determine conductivity

p-n junction:

current can only flow one way!

Semiconductor diode

p-n junction (diode)

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5.1. Introduction to semiconductors

5.1.1.Essentials on semiconductors

+ + + + + + + + accumulation

- - - - depletion

- - - - - - - - - - inversion

The field effect

5.1. Introduction to semiconductors

5.1.2.History of semiconductor technology

Over 35 years

The chip

contains

over a

million

MOS

transistors

The chip

contains

04 bipolar

transistors

IC Minimum

Feature Size

5.1. Introduction to semiconductors

5.1.2.History of semiconductor technology

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IC Minimum Feature Size

5.1. Introduction to semiconductors

5.1.2.History of semiconductor technology

Ultimate Small Scale Structure

5.1. Introduction to semiconductors

5.1.2.History of semiconductor technology

5.1. Introduction to semiconductors

5.1.2.History of semiconductor technology

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5.1. Introduction to semiconductors

5.1.2.History of semiconductor technology

1950 Junction Transistor

1950 - Alloy Junction Transistor

5.1. Introduction to semiconductors

5.1.2.History of semiconductor technology

1958 – First Planar Transistor

5.1. Introduction to semiconductors

5.1.2.History of semiconductor technology

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Basic Bipolar Paired Transistors

Bias “Resistor” NPN Bipolar Device Bias “Resistor”

5.1. Introduction to semiconductors

5.1.2.History of semiconductor technology

Modern Integrated Circuit Section

5.1. Introduction to semiconductors

5.1.2.History of semiconductor technology

SEM Cross-Section of Integrated Circuit

Wiring Layers

Wiring Layers

Wiring Layers

Vias through

Passivating Layers

CMOS Devices

5.1. Introduction to semiconductors

5.1.2.History of semiconductor technology

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5.2. Growth and process of semiconductor materials

5.2.1. Types of semiconductors.

1) Elemental semiconductors

2) Binary compounds

3) Oxide semiconductors

4) Layered semiconductors

5) Magnetic semiconductors

6) Amorphous semiconductors

7) Organic semiconductors

Lecture Content

5.1. Introduction to semiconductors

5.1.1.Essentials on semiconductors (“refreshing”)

5.1.2.History of semiconductor technology

5.2. Growth and process of semiconductor materials

5.2.1. Types of semiconductors.

5.2.2. Crystal growth and wafer fabrication

5.2.3. Physical and chemical vapor deposition (PVD&CVD).

5.3. Synthesis of one-dimensional nanostructures

5.3.1. Synthesis of carbon nanotubes.

5.3.2. Synthesis of metal oxide nanowires (NWs).

5.4. Nanostructures fabricated by physical methods

5.5. Practice on the synthesis of ZnO and SnO2 NWs

5.2.1. Types of semiconductors.

1) Elemental semiconductors

 The elements Si and Ge are well-kwon

semiconductors.

 Their crystal structures are the same as

diamonds.

 Some elements from the

group V and VI of the periodical

table such as P, S, Se, Te are

also semiconductors

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5.2.1. Types of semiconductors.

2) Binary compounds

Compounds formed from elements of the groups: III-V (such

as GaAs); II-VI (such as HgTe); I-VII (such as CuCl)

5.2.1 Types of semiconductors.

3) Oxide semiconductors

 CuO and Cu2O are well-known semiconductors.

SnO2 Eg=3.6 eV ZnO=3.37 eV

5.2.1 Types of semiconductors.

4) Layer semiconductors •Typical layer semiconductors are PbI2, MoS2,

GaSe.

•The bonding within layers is typically covalent.

•The behavior of electrons in the layer is quasi￾two dimensional.

•The interaction between layers can be modified

by incorporating foreign atoms.

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