THIS IS BASED ON PURELY ELECTRONICS ENGINEERING This course introduces basic concepts of quantum theory of solids and presents the theory describing the carrier behaviors in semiconductors. The course balances fundamental physics with application to semiconductors and other electronic devices. At the end of this course learners will be able to: 1. Understand the energy band structures and their significance in electric properties of solids 2. Analyse the carrier statistics in semiconductors 3. Analyse the carrier dynamics and the resulting conduction properties of semiconductors .

1. SEMICONDUCTOR DEVICES-
SPECIALIZATION
By- ABHISHEK SUR

2. Thereare3
Coursesinthis
Specialization
 SEMICONDUCTOR-PHYSICS
 DIODE- PN JUNCTION AND METAL
SEMICONDUCTOR CONTACT
 TRANSISTOR- FIELD EFFECT TRANSISTOR (FET)
AND BIPOLAR JUNCTION TRANSISTOR (BJT)

3. SEMICONDUCT
ORPHYSICS
 This course introduces basic concepts of quantum theory of solids
and presents the theory describing the carrier behaviours in
semiconductors. The course balances fundamental physics with
application to semiconductors and other electronic devices.
 At the end of this course learners will be able to:
1. Understand the energy band structures and their significance in
electric properties of solids
2. Analyse the carrier statistics in semiconductors
3. Analyse the carrier dynamics and the resulting conduction
properties of semiconductors

4. SEMICONDUCTORS
 There are some materials, which have neither good
conductivity nor bad conductivity of electricity.
 They have a moderate range of electrical conductivity.
 As the conductivity of those materials lies between
good conductors and insulators, and these materials
are called semiconductors.

5. SEMICONDUCTOR
….CONTD
 The atoms of semiconductor elements have exactly four
valence electrons.
 Because of these four valence electrons, the
semiconductor elements do have some special electrical
characteristics and properties, which make them
useful in using extensively in electronic circuit
elements like diodes, transistors, SCRs, etc.
 The resistivity of a semiconductor ranges from 10– 4 Ω –
m to 0. 5 Ω – m.
 Where the resistivity of copper is about 1.7 × 10– 8 Ω –
m in room temperature and resistivity of glass is about
9 × 1011 Ω – m.

6. Bonds in Semiconductor
 The valence electrons in semiconductor atoms take a vital role in bonding between atoms in the semiconductor crystal.
 Bonding between atoms occurs because each atom has a tendency to feel its outer most cell with eight electrons.
 Each semiconductor atom has four valence electrons, hence the atom can share four other valence electrons of
neighboring atoms to complete eight electrons in its outer most cell.
 The bonding between atoms by sharing valence electrons is called the covalent bond.

7. Commonly
used
Semiconductors
 There are many semiconductors but few of them are
used for electronic circuits.
 Two most commonly used semiconductors are silicon
and germanium.
 The silicon and germanium require lower energy to
break their covalent bonds in the crystal.
 This is the main reason for using these two
semiconductors most commonly.
 Silicon requires 1.1 eV for breaking any covalent bond
in its crystal and germanium requires 0.7 eV for the
same purpose.

8. N-TypeSemiconductors
 These are materials which have Pentavalent impurity
atoms (Donors) added and conduct by “electron” movement
and are therefore called, N-type Semiconductors.
 In N-type semiconductors there are:
 1. The Donors are positively charged.
 2. There are a large number of free electrons.
 3. A small number of holes in relation to the number of free
electrons.
 4. Doping gives:
 positively charged donors.
 negatively charged free electrons.
 5. Supply of energy gives:
 negatively charged free electrons.
 positively charged holes.

9. P-TypeSemiconductors
 These are materials which have Trivalent impurity
atoms (Acceptors) added and conduct by “hole”
movement and are therefore called, P-type
Semiconductors.
 In these types of materials are:
 1. The Acceptors are negatively charged.
 2. There are a large number of holes.
 3. A small number of free electrons in relation to the
number of holes.
 4. Doping gives:
 negatively charged acceptors.
 positively charged holes.
 5. Supply of energy gives:
 positively charged holes.
 negatively charged free electrons.

10. Othertypesof
Semiconductor
 Semiconductors are mainly two types
1. Intrinsic (Pure) Semiconductors
2. Extrinsic (Impure) Semiconductors

11. Intrinsic
Semiconductor
•A Semiconductor which does not have any kind of
impurities, behaves as an Insulator at 0k and behaves as
a Conductor at higher temperature is known as Intrinsic
Semiconductor or Pure Semiconductors.

12. Extrinsic
Semiconductor
 The Extrinsic Semiconductors are those in which
impurities of large quantity are present. Usually, the
impurities can be either 3rd group elements or 5th
group elements.
• Based on the impurities present in the Extrinsic
Semiconductors, they are classified into two categories.
1. N-type semiconductors
2. P-type semiconductors

13. HallEffect
 When a Magnetic field is applied perpendicular to a
current Carrying Conductor or Semiconductor, Voltage
is developed across the specimen in a direction
perpendicular to both the current and the Magnetic
field. This phenomenon is called the Hall effect and
voltage so developed is called the Hall voltage.
 Let us consider, a thin rectangular slab carrying
Current in the X-direction.
 If we place it in a Magnetic field B which is in the y-
direction.
 Potential difference Vpq will develop between the faces
p and q which are perpendicular to the z-direction.

14. THANK
YOU!!