Digital Electronics

 

Semiconductor

semiconductors are materials which have a conductivity between conductors  and insulators.

semiconductors can be pure elements,such as silicon or germanium 

 

 

p-type

n-type

 

n-type semiconductors, the majority of charge carriers are free electors where as the holes are minority.

 

p-type semiconductors, the majority of charge carriers are  holes where as the free electors are minority.

 

A junction between p-type and n-type semiconductor forms a diode.
 

Current flows only in one direction 

                  

  

 

 

 

Resistor

Resistor is a passive two terminals electrical component used for regulating the flow of electricity in a circuit .

 

                                     R=V/I

 

 

resistors in parallel

 

 

                                   1/Rt = 1/R1 + 1/R2 + 1/R3 + ...

 

 

resistors in series 

                                          R total = R1 + R2 +R3

 

 capacitor

 A capacitor is a two-terminal electrical device that can store energy in the form of an electric charge.

              C=Q/V

 

Capacitors in Parallel

 

                                              C Total = C1 + C2 + C3

 

capacitor in series

   

 

                            

Inductor

 an inductor is a passive electronic component that stores energy in the form of a magnetic field.

 V=L di/dt

 inductor in series :   

                                   L total =L1+L2+L3......

 

inductor in parallel :  

     

                                1/L=1/L1 + 1/L2 + 1/L3 ...

 Sand to Silicon process

raw material sand primarily mad up of silicon dioxide

sand combined with carbon and heated to an extremely high  temperate and remove the oxygen

metallurgical grad silicon

98% pure silicon

we need to 100% pure silicon

Siemens process 

98% silicon and hydrochloride acid add with reactor and heated

99.9999% pure silicon

go for CZ ( Czochralski ) process 

take furnace and add 99.9999% silicon combined with p type or n type importunity's add to furnace

in furnace mixing with silicon negates and type of impurities(trivalent or pentavalent ), sheet rode dip in furnace or crusable if crusable is rotating clockwise means, sheet rode will rotate anticlockwise direction, then we get ingot.

that ingot slices by using diamond then we get wafer by the chemical mechanical process smoothing the surface of wafer

 

                    

CMOS FABRICATION

 

Step1: Substrate
Primarily, start the process with a P-substrate.

 

Step2: Oxidation
The oxidation process is done by using high-purity oxygen and hydrogen, which are
exposed in an oxidation furnace approximately at 1000 degree centigrade.

                       si02

 

Step3: Photoresist

Photoresist is a light-sensitive organic polymer Softens when exposed to light