Zener Diode Invention & History

The Zener diode is a particularly valuable electronic component as it is able to provide a voltage reference for use in many electronic circuit designs including those of power supplies.

History of Semiconductor Diodes Includes:
PN junction diode invention LED history Zener diode invention

More semiconductor history
History of semiconductor technology development Transistor history Invention of the integrated circuit

The Zener diode is a particularly useful electronic component as it is able to give a stable voltage reference for use ina wide variety of circuits.

The Zener diode gains its name from the man who was researching breakdown mechanisms in semiconductor diodes and discovered the Zener effect. As a result of its importance Zener was honoured by referring to these diodes as Zener diodes.

Are all voltage reference diodes Zener diodes

Although most voltage reference diodes are called Zener diodes, there are two effects that exist within these diodes.

The first is the Zener effect which tends to be more predominant in diodes with voltages below about 5.5V. In involves a tunnelling effect to cause the breakdown.

Above voltages of about 5.5V the Zener effect becomes less pronounced and another breakdown effect known as avalanche breakdown or impact ionisation occurs.

Although the result is almost the same which ever effect is used, they do tend t have opposite temperature coefficients which makes diodes with voltagees around 5.5.V the most temperature stable as the coefficients tend to cancel, reducing any movements resulting from temperature changes.

Who was Zener?

The Zener diode is named after Dr. Clarence Melvin Zener (pronounced Zee-ner), a physicist who undertook research into the breakdown mechanisms of semiconductor materials.

Zener was born in 1903 in Indianapolis. In many ways he was an unlikely child to progress on to a researcher as he had a problem with stuttering or stammering and he did not read properly before the age of 10.

Nevertheless he developed a confidence in self learning and managed to enter Stanford University at the age of 16 from which he graduated in 1926 before moving on to Harvard where he earned a Ph.D. in physics in 1929.

Having graduated he spent time at Princeton University and also in the UK at Bristol University where he explored where his talents might be most usefully deployed.

One area where he saw he might be able to contribute was in the area of the reverse bias breakdown of semiconductor diodes. This was a field at the time where little was known because semiconductor diodes as we know them today had not been fabricated at this time.

In 1934 Zener wrote a paper on the electrical breakdown of materials.