What is an ic(integrated circuit)

Ic means integrated circuit .It is the assembly of the elctronic components.diffused on a silicon wafer.

Ic is made in a monolythic form,film type form and hybrid type.

ADVANTAGES OF IC OVER DISCRETE CIRCUIT:-

• Ic is very small in size
• Cheaply available
• Less space required
• Large circuit in a small chip
• Easy to fabricate
• Very fast actions
• Less noise
• Less power consumption
• No distortions
• Easy to design
• No power loss
• High gain
• No lekages of power, etc.

MONOLYTHIC IC FABRICATION:-

In MONOLYTHIC ic fabrication we aminly use 6 steps for ic fabrication:

1. Preparing substrate or silicon wafer
2. Forming n-epitaxial layer
3. Insulation process 
4. Photo etching process
5. Metalization and oxidation or preparing components
6. Packaging of IC

1}PREPARING OF SILICON WAFER:-

                       

     A silicon wafer is prepared by the above process.it is cut by a diamond.

Next to this process we go to forming n epitaxial layer.

2}N-EPITAXIAL LAYER FORMING:-

This n-epitaxial layer is formed by passing pentavalent impurities in to the furnance at 1200°c temperature.

3}FORMING INSULATION LAYER:-

    Insulation layer is used to protect the ic . It is done by oxidation process at 110°c .

It is done in two ways:

  1)dry oxidation:-   oxygen is passed from the furnance for forming insulating layer this oxygen reacts with the silicon wafer and forms insulating layer

  2)wet oxidation:-   water is passed from the furnance for forming the insulating layer.water will be evaporated after reaction at 110°C temperature.

4)PHOTO ETCHING PROCESS:-

              

Photoetching means a window opening of the IC to form the electronic components. UV rays are entered in to the silicon wafer by window openings. A photo resistive material is used at the another place where window opening os not done.

5)preparing components:-

              

Diffusing the n or p type layers as per our requirements is called diffusion or forming of components on ic.

We produce various components on ic by this process.

    Preparing of different types of components on ic:-

   Resistor:-

  Capacitor:-

  Transistor:-

  Diode:-

6)Ic packaging:-

Ic is packed in different types 

Dual in line packaging,

Transistor type,

Flat type.

DISADVANTAGES OF IC :-

1)cannot be repaired 

2)large components like inductor and relays and transformers cannot be build on ic