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History of Semiconductor Engineering
General
Written by Gizmo   
Monday, 22 January 2007 20:09

Read the full book review at Electronic Design:

"Once upon a time, if you wanted to make a junction transistor, you could start with a small seed crystal of pure germanium. Using Czochralski’s 1917 methods, the crystal was gradually rotated and pulled out of a lightly doped N-type material and grown into a small boule. After suitable growth, a small amount of acceptor impurity such as gallium was added to the melt, causing the germanium to form a PN junction. This was all consistent with the theory of William Shockley, published in June 1949.

The making of simple PN junctions was not that new. Then, Morgan Sparks of Bell Labs added a stronger impurity (antimony) to make a second closely spaced junction and keep the crystal growing. On April 12, 1950, the first junction (NPN) transistor was born, and all hell broke loose. Hundreds of inventions were added to make better transistors.

But this grown-junction transistor was hard to make, as the base area was barely 25 µm thick and hard to connect to. Many efforts, both theoretical and practical, went into making practical transistors. Yet for a long time, the performance was still lousy, and the yields were still poor—a β of 40, f(α) of 15 MHz, and breakdown of 25 V was considered"

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