What is semi conductor ??

 

Writer Name: MD. Fardin Jaman Aranyak 

Date: 4 November, 2020

What is semiconductor??

a solid substance that has a conductivity between that of an insulator and that of most metals, either due to the addition of an impurity or because of temperature effects. Devices made of semiconductors, notably silicon, are essential components of most electronic circuits.

If an atom valence band is almost fill with electrons and its conduction band is empty where energy difference between valance band and conduction band is close to 1.1 electron volt is called semi-conductor.

When an electron comes to conduction band from valence band it creates hole in valence band. The hole bear positive charge.

What is valance band and conduction band?

 the valence band is the highest range of electron energies in which electrons are normally present at absolute zero temperature, while the conduction band is the lowest range of vacant electronic states

Type of semi-conductor:

·      Extrinsic

This type of semiconductor intentionally impurities is added for making it conductive

·      Intrinsic

This type of semiconductor is pure.

 

p-type and n-type semiconductor:

p type semi-conductor:

          if we add some trivalent element as an impure element to the intrinsic semiconductor is called p type semi-conductor.  Ex if we add only one atom of aluminum to the silicon semiconductor it will create p type semi-conductor. Because every silicone connects with 4 silicone in its structure and it has 4 valance bonds. On the other hand, aluminum have 3 electrons in its valence cell, so it will create a hole if we add aluminum into silicone as an impure element.

 

N type semi-conductor:

if we add some pentavalent element as an impure element to the intrinsic semiconductor is called N type semi-conductor. Ex if we add only one atom of phosphorus to the silicon semiconductor it will create N type semi-conductor. Because every silicone connects with 4 silicone in its structure and it has 4 valance bonds. On the other hand, phosphorus has 5 electrons in its valence cell, so it will create a free electron if we add phosphorus into silicone as an impure element

What is Diode?

Diode, an electrical component that allows the flow of current in only one direction. In circuit diagrams, a diode is represented by a triangle with a line across one vertex. Diode is made of p-n junction. A p–n junction is a boundary or interface between two types of semiconductor materials, p-type and n-type, inside a single crystal of semiconductor

Transistor

The transistor is a semi-conductor device which transfers a weak signal from low resistance circuit to high resistance circuit. You can see two type of transistor in real life word N-p-N transistor and P-n-P transistor.

N-P-N transistor:

P-N-P Transistor:

*** If you want to add two transistors In a same circuit than you need to add one emitter to another as a Base.

Equation:

Total electricity passes through emitter is summation of base current and collector current

I_E=I_B+I_C

Current amplification Factor:

α=(Ic/I_E)

Current Gain:

β=(Ic/I_B)

Voltage Gain:

V_b= β(R_f/R_i)   R_f = Weight resistance R_{i =} Internal resistance

 

Transistor is used to make CPU and the latest architecture is Finfet technology. Finfet technology first used by intel co.

Inter Core i7 8 gen have 3 billion transistors