1. SOLID STATE DEVICESSOLID STATE DEVICES
POWERPOINT PRESENTATION ONPOWERPOINT PRESENTATION ON
PROJECT REPORTPROJECT REPORT
Submitted in partial fulfillment of theSubmitted in partial fulfillment of the
Requirement for the award of the degreeRequirement for the award of the degree
OfOf
BACHELOR OF SCIENCESBACHELOR OF SCIENCES
InIn
PHYSICSPHYSICS
SUBMITTED BY:
RAJNI TRIPATHI
2. TALKFLOW
• Solid state devices – Introduction.
• P and N type Materials.
• PN Junction.
• Diode and its types.
• Transistor and its types.
• Integrated circuits.
• Advantages of Solid State
Devices.
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3. What Are SOLID STATE DEVICES
Made Out Of?
• Silicon (Si) and Germanium (Ge) are the two most common single elements that
are used to make Diodes.
• Silicon and Germanium are both group 4 elements, meaning they have 4 valence
electrons.
• Their structure allows them to grow in a shape called the diamond lattice.
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4. N-Type Material
•When extra valence electrons are introduced into a material such as silicon an
n-type material is produced.
•The extra valence electrons are introduced by putting impurities or dopants
into the silicon.
•The dopants used to create an n-type material are Group V elements.
•The most commonly used dopants from Group V are arsenic, antimony and
phosphorus.
•The extra electron is very mobile.
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5. P-Type Material
•P-type material is produced when the dopant that is introduced is from Group III.
•Group III elements have only 3 valence electrons and therefore there is an electron
missing.
•This creates a hole (h+), or a positive charge that can move around in the material.
•Commonly used Group III dopants are aluminum, boron, and gallium.
•This hole is quite mobile in the same way the extra electron is mobile in a n-type
material.
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6. The PN Junction
Steady State
When no external source is
connected to the pn
junction, diffusion and drift
balance each other out for
both the holes and electrons
Space Charge Region: Also called the depletion region. This region includes the net
positively and negatively charged regions. The space charge region does not have any
free carriers. The width of the space charge region is denoted by W in pn junction
formula’s.
Metallurgical Junction: The interface where the p- and n-type materials meet.
Na & Nd: Represent the amount of negative and positive doping in number of carriers
per centimeter cubed. Usually in the range of 1015
to 1020
.
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7. The Biased PN Junction
PP nn
++__
Applied ElectricApplied Electric
FieldField
MetalMetal
ContactContact
““OhmicOhmic
Contact”Contact”
(Rs~0)(Rs~0)
++ __
VVappliedapplied
II
The pn junction is considered biased when an external voltage is applied. There
are two types of biasing: Forward bias and Reverse bias.
These are described on then next slide.
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8. The Biased PN Junction
Forward Bias:Forward Bias:
In forward bias the depletion region shrinks slightly in width.
With this shrinking the energy required for charge carriers to
cross the depletion region decreases exponentially. Therefore,
as the applied voltage increases, current starts to flow across
the junction. The barrier potential of the diode is the voltage
at which appreciable current starts to flow through the diode.
The barrier potential varies for different materials.
Reverse Bias:Reverse Bias: Under reverse bias the depletion region widens. This causes
the electric field produced by the ions to cancel out the
applied reverse bias voltage. A small leakage current, Is
(saturation current) flows under reverse bias conditions. This
saturation current is made up of electron-hole pairs being
produced in the depletion region. Saturation current is
sometimes referred to as scale current because of it’s
relationship to junction temperature.
VVappliedapplied > 0> 0
VVappliedapplied < 0< 0
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9. Types of Diodes and Their Uses
PN JunctionPN Junction
Diodes:Diodes: Are used to allow current to flow in one direction while
blocking current flow in the opposite direction.
Schematic Symbol for a PNSchematic Symbol for a PN
Junction DiodeJunction Diode
Representative Structure for a PNRepresentative Structure for a PN
Junction DiodeJunction Diode
Zener Diodes:Zener Diodes: Are specifically designed to operate under reverse
breakdown conditions. These diodes have a very
accurate and specific reverse breakdown voltage..
Schematic Symbol for a ZenerSchematic Symbol for a Zener
DiodeDiode
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10. Types of Diodes and Their Uses
Schottky Diodes:Schottky Diodes: These diodes are designed to have a very fast switching
time which makes them a great diode for digital circuit
applications. They are very common in computers
because of their ability to be switched on and off so
quickly.
Shockley Diodes:Shockley Diodes: The Shockley diode is a four-layer diode while other
diodes are normally made with only two layers. These
types of diodes are generally used to control the average
power delivered to a load.
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11. Types of Diodes and Their Uses
Light-EmittingLight-Emitting
Diodes:Diodes:
Light-emitting diodes are designed with a very large
bandgap so movement of carriers across their depletion
region emits photons of light energy. Lower bandgap
LEDs (Light-Emitting Diodes) emit infrared radiation,
while LEDs with higher bandgap energy emit visible
light. Many stop lights are now starting to use LEDs
because they are extremely bright and last longer than
regular bulbs for a relatively low cost.
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12. Types of Diodes and Their Uses
Photodiodes:Photodiodes: While LEDs emit light, Photodiodes are sensitive to
received light. They are constructed so their pn junction
can be exposed to the outside through a clear window or
lens.
In Photoconductive mode the saturation current
increases in proportion to the intensity of the received
light. This type of diode is used in CD players.
In Photovoltaic mode, when the pn junction is exposed to
a certain wavelength of light, the diode generates voltage
and can be used as an energy source. This type of diode
is used in the production of solar power.
λλ
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13. Transistors
• A Transistor is an semiconductor which is a fundamental component in
almost all electronic devices.
• Transistors are often said to be the most significant invention of the 20th
Century.
• Transistors have many uses including switching, voltage/current regulation,
and amplification - all of which are useful in renewable energy applications.
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14. Function of Transistors
• Transistors amplify current, for example they can be used to
amplify the small output current from a logic chip so that it can
operate a lamp, relay or other high current device. In many
circuits a resistor is used to convert the changing current to a
changing voltage, so the transistor is being used to amplify
voltage.
• A transistor may be used as a switch (either fully on with
maximum current, or fully off with no current) and as an
amplifier (always partly on).
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15. Types of Transistors
•There are two types of standard transistors, NPN and PNP,
with different circuit symbols.
•The letters refer to the layers of semiconductor material used
to make the transistor.
•The leads are labeled base (B), collector (C) and emitter (E).
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16. •Integrated Circuits are usually called ICs and popularly known as
a silicon chip, computer chip or microchip.
•It is usually combined with other components to form a more complex
system.
Integrated Circuits
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17. • Several hundred identical integrated circuits (ICs) are
made at a time on a thin wafer several centimeters wide,
and the wafer is subsequently sliced into individual ICs
called chips.
IC Fabrication
17
18. • SSI (small-scale integration): Up to 100 electronic components per chip
• MSI (medium-scale integration): From 100 to 3,000 electronic
components per chip
• LSI (large-scale integration): From 3,000 to 100,000 electronic
components per chip
• VLSI (very large-scale integration): From 100,000 to 1,000,000 electronic
components per chip
• ULSI (ultra large-scale integration): More than 1 million electronic
components per chip
IC Types
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19. • Digital integrated circuits can contain anything from one to millions of logic
gates, flip-flops, multiplexers, and other circuits in a few square millimeters.
• The small size of these circuits allows high speed, low power dissipation, and
reduced manufacturing cost compared with board-level integration.
• These digital ICs, typically microprocessors, DSPs, and micro controllers, work
using binary mathematics to process "one" and "zero" signals.
Digital Integrated Circuits
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20. • Analog ICs, such as sensors, power management circuits,
and operational amplifiers, work by processing continuous signals.
• They perform functions like amplification, active
filtering, demodulation, and mixing.
Analog Integrated Circuits
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22. 1. Extremely small size—thousands times smaller than discrete
circuit. It is because of fabrication of various circuit elements in a
single chip of semi-conductor material.
2. Very small weight owing to miniaturized circuit.
3. Very low cost because of simultaneous production of hundreds of
similar circuits on a small semiconductor wafer. Owing to mass
production an IC costs as much as an individual transistor.
4. More reliable because of elimination of soldered joints and need for
fewer inter-connections.
5. Low power consumption because of their smaller size.
Advantages of Solid State Devices
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23. 6. Easy replacement as it is more economical to replace them than to
repair them.
7. Increased operating speeds because of absence of parasitic
capacitance effect.
8. Close matching of components and temperature coefficients because
of bulk production in batches.
9. Improved functional performance as more complex circuits can be
fabricated for achieving better characteristics.
10. Greater ability of operating at extreme temperatures.
Advantages of Solid State Devices
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