Why Silicon (Si) Diodes are Preferred over Germanium (Ge) Diodes?

As we know, both Silicon and Germanium are semiconductor devices. But the present trend is to use Silicon instead of Germanium in many devices like SMPS etc.

The reasons for using Silicon Diodes over Germanium Diodes this are:

  • At room temperature, Silicon crystal has fewer free electrons than Germanium crystal. This implies that silicon will have much smaller Collector cut off current than Germanium.

  • The variation of Collector cut off current with temperature is less in Silicon compared to Germanium.
  • The structure of Germanium crystals will be destroyed at higher temperature. However, Silicon crystals are not easily damaged by excess heat.
  • Peak Inverse Voltage ratings of Silicon diodes are greater than Germanium diodes.
  • Silicon is less expensive due to the greater abundance. The major raw material for Silicon wafer fabrication is sand and there is lots of sand available in nature.

But there is a disadvantage for Silicon over Germanium.

The potential Barrier of Silicon is more compared to Germanium. The potential barrier for Silicon is 0.6 to 0.7 V while for Germanium is 0.2 V.

But if we consider the advantages of Silicon, we can conclude that Silicon is the best element for the Semiconductor Devices and Applications.

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