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January 2017 – Silicon Diodes vs. Germanium Diodes – Which is the Preferred Semiconductor Device?

Published on: 12/01/2017

Learn why one semiconductor device is preferred over the other

Silicon Diodes vs. Germanium Diodes


A silicon diode is a semiconductor that has both positive and negative charge polarity and can allow an electrical current to flow in one direction whilst restricting another. A germanium diode works in the same way but has a low forward voltage which results in it being a low power loss and an efficient diode.

Silicon diodes have a forward voltage of approximately 0.7 volts whereas germanium diodes have a forward voltage of approximately 0.3 volts.

Today silicon diodes are preferred over germanium diodes for rectifier circuits in Switched Mode Power Supply (SMPS).


Silicon Diodes vs. Germanium Diodes

Why are Silicon Diodes Preferred over Germanium Diodes?

1. The variation of collector cut off current with temperature is less in silicon compared to germanium

2. Silicon crystal has fewer free electrons than germanium crystal at room temperature. Silicon is likely to have much smaller collector cut of current than germanium

3. The structure of germanium crystals gets destroyed at a higher temperature. Unlike germanium, Silicon crystals are not easily damaged by excess heat

4. Silicon is more cost effective due to the greater abundance of the element. The major raw material for silicon wafer fabrication is sand and there is lots of sand readily available

5. Peak inverse voltage ratings of silicon diodes are far greater than germanium diodes


GD Rectifiers distribute and stock a wide range of reliable high power semiconductors using conventional and future technologies. They design and manufacture Selenium and Silicon rectifiers, suppressors, converters, inverters, and regulator products for Industrial power control applications.

They hold extensive stock of diodes, thyristors, IGBTs and MOSFETs from the world’s leading semiconductor manufacturers, including IXYS, IXYS UK Westcode and Semikron.

Offering a full service from design to production, technical support and fast delivery, GD Rectifiers is the No.1 semiconductor provider in the UK.


For further information on all silicon rectifier diode products please call our friendly sales team for a quote today on: 01444 243 452 or email:

Find out more about the latest GD Rectifiers product range here.


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