Semiconductor and devices

Semiconductor Devices

By

Md.Rabius Sani

Biplob Sarker

Fahmida Hossain

Bappy Das

15.04.2023 Semiconductor Devices 2

●Introduction●Types of Semiconductor Devices●Diode●Forward & Reverse Bias●Transistor●Types of transistors●Queries


Introduction●Semiconductor:●Unit which consists lagely or wholly,of semiconductor materials which can perform useful function in electronic apparatus & solid state research.●Ex:p-n jun diode,transistros,IC's and etc.


Types of Semiconductors

●There are two types of Semiconductors● 1)Intrisic Semiconductors● 2)Extrinsic Semiconductors●Intrinsic Semiconductors:Tetravalent● Ex:Si,Ge etc●Extrinsic Semiconductors:

Ex:p-type and n-type


DIODE

●Diode is device with two electrodes.●A p-n juncion diode is a two terminal device made up of semiconductor crystal.●P-N junction diode

+ -

P-n junction diode ckt symbol


Forward Bias

●Resistance is very small

+ - mADepletion Layer

B

p n

P-n junction-Forward Bias


Reverse Bias●Resistance is very high●Conduction is due to thermal agitation.

Depletion Layer

B

+-

p n

MA

P-n junction-Reverse Bias


Transistors●Invented in 1948●A transistor is a semiconductor device used to amplify and switch electronic signal.●Consist of two p-n junctions back to back●Has three regions:●1)Emitter●2)Base●3)Collector


●Base is made up of P-type●Current conduction is mainly due to holes

P-N-P Transistor

ppp pn

Ckt symbol of p-n-p transistor

E

B

C

p-n-p transistor


N-P-N Transistor

●Base is made up of p-type.●Current conduction is mainly due to electrons.

E C

B

n npCkt symbol of n-p-n transistor

n-p-n transistor


Advantages●Used in microcircuits.●They're quite strong&sturdy.●Usually,they've long life.●Swithches turn on&off with the use of transistor.


ANY QURIES?

●Can two diodes combined back to back as shown in●fig to form a transistor?

P N N P


THANK YOU

Semiconductor and devices

Engineering

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