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

1. MODULE 4.1
Semiconductors

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.

9. Atoms of semiconductors
 Silicon  Germanium

10. Covalent Bonding
 Single Atom
 Crystallize Structure/ lattice

11. Semi Conductor
 N Type
 P Type

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