25) "Mesa-Type" Opened the Way to the Full-scale Transistor Era
Photo A: Dot-Mesa Transistor made by Hitachi Ltd.,
Photo B: Mainichi Shimbun reported Hitachi was awarded the Mainichi Industry
Technology Award
for the Dot-Mesa transistor (Enlargeable)
The first transistor manufactured by diffusion technology was
mesa-type. The cross section of the device is similar to a landscape of trapezoidal
hills (mesa) often seen in Western movies. That's why it was named as mesa-type.
This transistor was excellent in the high-frequency characteristics, operating
at as fast as 500MHz, and then made a large contribution to the superior performance
of Japanese radios and televisions.
This technology was developed by Bell Telephone Laboratories first and introduced
to Japan in or about 1957. Combining this technology with the conventional
alloy-type and grown-type one, "Alloy-diffusion type" and "Grown-diffusion
type" respectively were developed and put into practical use by Matsushita
Electronics Industry Corporation and by NEC respectively. Hitachi developed
their original product called "Dot-mesa type" transistor and put
it in the merchant market. In 1961 the production of transistors already surpassed
that of electron tubes in terms of volume as well as amount, and that entirely
owed to the mesa-type.
Photo A shows "Dot-mesa type" transistor developed in 1959 and mass-produced
in 1961 by Hitachi, for which Hitachi was awarded the Mainichi Industrial
Technology Award in 1963. Photo B shows the article in the Mainichi saying
Hitachi established mass-production process of a high frequency transistor
first in the world, thanks to easiness of controlling the position of electrode
junction, which was highly appraised.
(Source: "20 Years History of Musashi Works" by Hitachi Ltd.,)