The slide is used for classroom lecture for module 4 of EASA B1.1 license course. Part of the module to unable student to understand how semi conductor works
2. Syllabus Part 66
Module 4.1 (B1.1 Excluded) (B2 – Level
2)
Materials, electron configuration,
electrical properties;
P and N type materials: effects of
impurities on conduction, majority and
minority characters;
PN junction in a semiconductor,
development of a potential across a PN
junction in unbiased, forward biased &
reverse biased conditions;
3. Comments on Syllabus
Although it is not included, however,
without knowledge of the
semiconductor, a student will not be
able to understand how a diode or
transistor works.
Due to this requirement, the subject is
included in the program.
4. Introduction
Modern Electronics
◦ 19th Century – Thomas Edison discovered
heated metal emitted charged particles.
Led to discovery of thermionic valve.
◦ 1940 – transistor was invented by Bell
Laboratories
◦ 1950s’ – development of integrated circuit
◦ 1960s – prediction that the number of
transistors in IC would be doubled every 18
months.
◦ 2007 – an advanced IC contained 55 mil
transistors
5. Atomic Structure
◦ 1913 – Bohr – Beginning of the basic
theory of atomic structure.
6. Valence Shell
The tendency of atoms to gain
or loss electrons depends on
the number of electrons in
the outmost shell.
The outmost shell is known as
valence shell and the electrons is
known
as valence electrons.
7. Energy Bands
x-axis- the allowed energy levels numbered
from 1 to 5. The y-axis shows each level's
energy in electron volts (eV)
One electron volt is the energy that an electron
gains when it travels through a potential
difference of one volt (1 eV = 1.6 x 10-19 Joules).
8. Energy in Atoms
As in previous slide, the energy level is
discreet.
Electrons are in either conduction bands
or valence band.
Materials with large amount of electrons
in the conduction bands are good
conductor.
12. Electron Flow Hole Flow
Doped with Arsenic
Conduction
Intrinsic flow – there is no impurities added
13. Doping Process …
A pure silicon or germanium are
insulator. It has valence electrons of 4.
Adding impurities will change the
characteristic of the semiconductor.
If elements with 5 valent electrons is
added, it will have one electron
balance, thus become N-type,
negative type with electrons as the
current carrier.
14. … Doping Process
If an element with 3 electrons is added,
then it will be P-type with holes. P type or
positive type will conduct current via
holes, similar to the conventional flow of
current.
Example of impurities for N-types are
arsenic and phosphorous.
Example of impurities with 3 valent
electron and used to manufacture P type
semiconductor is boron, gallium and
indium.
15. N-type semiconductor
The doping is done by 5 valence
electrons – pentavalent impurity.
◦ Example arsenic, antimony, bismuth and
phosphorous.
16. P-Type Semiconductor
Doping with impurities with 3 valence
electrons or trivalent will produce a P-
type semi-conductor.
◦ Example of trivalent materials are –
alluminium, indium, gallium, boron
◦ Concept of minor and major carriers.
17. RESOURCES
My Blog Recommended Books
Title Autho ISBN
r
Aircraft Electricity Eisma 0-02-
and Electronics n 801859-1
Art of Horowi 0-521-
tz /Hill 37095-7
Electronics
Horowitz /Hill
Elements of Hickey/ 0070286957
Villines
Electronics
Modern Aviation Helfric 0-13-118803-
Electronics h 8
Micro E 0-273-
Electronics in Pallet 08612-X
Aircraft systems