Elmer Wolff Jr


Oral History – Elmer Wolff Jr (Continued)


My orientation covered the entire transistor process, from refining germanium, to growing single crystals, cutting the crystal into small pieces for point contact transistors, or cutting the grown junction from the crystal and cutting the grown junction bars from the germanium slab, mounting the bars into headers, etching, wire bonding to the junction, encapsulation and electrical testing.  One thing that really stood out in my orientation was the observation that all the equipment had to be designed and built by TI.  There was no industry infrastructure to support early semiconductor activity. 


The semiconductor “project” moved within the first month or so after I joined TI.  This move was driven by the need for more space and the difficulty in growing single crystal germanium with the floor vibrations coming from the machine shop punch presses.  During the single crystal growing procedure, if the puller was jarred, you had a better chance than not of causing a “twinning” in the crystal structure – this meant that the crystal was of no use and you had to start over. 


The “project” moved across the side street to what had been a bowling alley.  This provided open space that we needed, but the air-conditioning system was not designed for the heat load that was brought into the building, and we had a virtual sauna in the summer months.  Texas summers are well known for many days above 100 degrees F.    



Oral History – Elmer Wolff Jr (Continued)


The first step in the building of a transistor, other than refining the material, was to turn the germanium into a single crystal structure.  Crystal growing of semiconductor materials at that time was part science, part magic and a big dose of technique, with some prayers thrown in for added insurance.  The crystal puller that we had at that time sported some dents in the quarter inch aluminum frame, with additional shoe and boot marks imprinted on it, evidence of earlier frustrating “caresses” when it (we) didn’t achieve the results we were hoping for.  You could not purchase a crystal puller, a wire bonding machine or any other similar equipment that was required to build the original transistors – you could buy the basic stuff such as volt/current meters and oscilloscopes.  The test equipment was crude by today’s standards. As a matter of fact, the ongoing evolution of complex semiconductor devices, including integrated circuits, is the vehicle that made possible the sophisticated assembly and test equipment that we now take for granted.


My first assignment was to learn the process for assembly of the point contact transistor and to perform electrical characterization. This assignment did not last very long since TI discovered that no one was buying any point contact devices and this transistor soon disappeared. 


Wolff Oral History, Page 3


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