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Oral History – Elmer Wolff Jr (Continued)
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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.
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Oral History – Elmer Wolff Jr (Continued)
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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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