03/12/2017

Compare Silicon and Germanium

Why Silicon is Preferred over Germanium ?
However silicon is mostly preferred as semiconductor as compared to germanium due to following reasons.
  • The atomic number of germanium is 32 therefore the number of electrons in the first orbit is 2, second orbit is 8, third orbit is 18 and fourth or last is orbit 4. 
  • The atomic number of silicon is 14 therefore the number of electrons in the first orbit is 2, second orbit is 8 and third or last orbit is 4.
  • Therefore the germanium material has valanceelectrons are at higher energy level ( fourth orbit ) as compared to silicon material ( third orbit ). 
  • It means that germanium material requires some additional energy to free electrons from last orbit. This property makes germanium unstable at higher temperature.
  • The working temperature of the germanium is approx 700C whereas it is 1500C for the silicon.
  • The variation of the collector leakage current with temperature in the germanium is more than that of silicon.
  • At room temperature, the collector leakage current in the silicon is much smaller than that of germanium. 
  • The collector leakage current in the germanium material is approx. 10 to 100 times greater than that of silicon type material.


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