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)

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“Mr. Shimura’s Essays with Historic Photos”    Semiconductor History Museum of Japan
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