10) Pursuing All-Made-in-Japan Single Crystals
Photo A: The trial equipment of single crystal drawing
Photo B: Germanium single crystal produced by the equipment shown in photo
A
Although the group of Research Institute for Electrical Communication
succeeded in making the first functional samples of transistors in Japan,
they were not entirely satisfied by this accomplishment. It was because the
utilized germanium crystals were not made in Japan. The Research Institute
started to make single crystals of high purity germanium under the slogan
of "Our next step is to realize all-made-in-Japan."
In order to make single crystals, crystal drawing equipment was indispensable.
Iwase and other members worked energetically, including visits to the laboratories
at Yamanashi University and studying the method of growing synthetic quartz
from seed crystals, and Bernoulli’s method to grow artificial ruby and artificial
sapphire.
The problem they faced at when they started to make crystal drawing equipment
was that inert gases such as argon and nitrogen which were used in the chamber
in US were not available in Japan. So, they adopted an alternative method
of drawing crystals in a vacuum chamber. But impurity gases were inevitably
generated from the furnace in high vacuum environment at the temperatures
as high as 1,000 °C. They contrived several new measures including winding
cantle wires inside the pure alumina furnace body, and the single crystal
was finally completed. Photo A is the outside appearance of the equipment,
and Photo B is the germanium single crystal made by using this equipment.
The equipment was an epoch making product in those days, and they also tried
to obtain patents. The entrusted equipment maker, however, had already started
the outside sales of the equipment without their permission.
Later, Iwase told, "I was very surprised to see a photograph in the brochure
distributed to the invited guests showing equipment which was almost exactly
the same as the one we made, when I visited Sony in Shinagawa on the opening
ceremony of their transistor factory."
(Photo: by courtesy of Shingo Iwase)