26) Measuring Instrument Converted from a Photo Enlarger

 
Photo: A measuring instrument made by Hitachi Ltd., to measure lifetime of Ge single crystals

There were neither materials nor measuring instruments available for semiconductor development in Japan, when it was started literally from scratch. Even after signing a contract with Western Electric Company to obtain the technological know-hows, Japanese companies could receive only three volume text of "Transistor Technology." They, therefore, had to develop all the necessary equipment by referring to the simple figures and photos in those books.
In those days I had heard Tetsuo Tsukamoto, who was a key person of the transistor development group at Sony, mutter "I wish I could see the backside of this instrument shown on the photo by turning it over." I could not laugh at it.
Likewise, they had to develop testing equipment and measuring instruments by themselves, too. The photo shows a measuring instrument made by Hitachi to measure lifetime of Ge single crystals which employed so called light injection method. They first set up a fixed needle electrode on a bulk crystal and applied a reversed bias to it. Then, they measured the amount of minority carrier current into the needle electrode, while changing the relative position of focused light in slit-shape against the needle.
Takashi Tokuyama, a chief researcher of Central Research Laboratory of Hitachi at the time said, "Since no commercial equipment was available, we utilized an upper light source by remodeling that of a photo enlarger. The lifetime of the first crystal we grew was 7 micro second." (By courtesy of Tokuyama)

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