29) Birth of Micro TV with Adoption of Epitaxial Technology
Photo: Five inch micro TV "TV5-303" produced by Sony Corporation
Two process technologies, "Epitaxial" and "Planer"
played important roles as driving force for rapid shift from Germanium to
Silicon. Both technologies were developed in the US, in the 1960’s, the dawn
of Silicon era.
The name of Epitaxial came from the combination of two Greek words, Epi (on
top of) and Taxis (an ordered manner). Epitaxial technology is literally the
technology of growing a thin film of high purity single crystal on top of
a silicon single crystal substrate, with the same crystal axis as the substrate.
By adopting this technology, the active area of device itself is formed in
the thin film layer, realizing dramatic improvement of device characteristics.
Tetsuo Tsukamoto of Sony Corporation, by knowing that this technology was
developed by Bell Telephone Laboratory (BTL) and that it was applied to telecommunication
transistors, quickly understood by intuition that this technology would be
useful for the performance improvement of transistor TV, which had been their
long time subject.
At that time, Sony developed high frequency, high power transistors using
silicon crystal made by Sony’s own pulling equipment which they developed.
And they produced the world first 8-inch transistor TV, by using these transistors.
But the TV products had several problems, like unclear and dark picture images,
weak sensitivity when only using rod antennas, high failure rate, etc., and
the market reputation was not so good.
Tsukamoto, knowing that these problems were caused by the silicon transistors,
headed the "Operation Micro TV." He decided to adopt epitaxial technology,
and carried out this development confidentially. Fortunately, in August, two
months later, he succeeded in establishing the fundamental process, and in
October, he completed the development of high frequency high power transistors
using epitaxial wafers. There is a famous story that the engineers of BTL,
inventors of epitaxial process themselves, were surprised at the high level
of completion of the devices.
Photo: Five-inch micro TV "TV5-303" using these transistors (By
courtesy of Sony)