By 1948, Morton had
achieved a reputation as an imaginative
engineer who knew how to get sophisticated devices into
production. One day in June, Kelly tersely summoned him
to his office. Such a one-on-one encounter was not to be
taken lightly, for Kelly—who had risen to executive
vice president—had a legendary temper. A friend of
Morton’s later described the meeting as follows:
“Morton,” Kelly began, “You do know about the work
we’ve been doing on the transistor?”
“Yes, sir,” Morton replied a bit hesitantly. He’d
heard through the grapevine about the transistor, the
secret new solid-state amplifier invented the previous
December by Bardeen and experimental physicist Walter
Brattain, but he was unsure whether to admit it. “At
least I know it’s pretty important.”
“Morton, I’m going to be away for the next four
weeks,” Kelly proceeded imperiously. “When I get back, I
would like to see a report from you on the transistor. I
want you to tell me how to develop it commercially.”
Kelly didn’t know it, but Morton had been running
scared of him ever since being hired, and he was now
terrified at the prospect of failing on such an enormous
assignment. For the next three weeks Morton talked to
the scientists and engineers working on transistors but
made little progress. Then, in the last week, he somehow
pulled it all together and had a 46-page report waiting
on the boss’s desk when he returned. Kelly read it,
approved it, and immediately put Morton in charge of
transistor development.
Bardeen and Brattain’s point-contact transistor was a
crude, fragile device consisting of two closely spaced
metal points jabbed into a germanium sliver. That it
worked at all was a minor miracle. Already a pilot
production line at the Labs was turning out hundreds of
prototypes every week for further experimentation,
measurement, and testing. But the transistors were
extremely noisy, variable, and unreliable. “In the very
early days, the performance of a transistor was apt to
change if someone slammed a door,” Morton was quoted as
saying in a 1953 article in Fortune.
In the fall of 1948, he gathered about a dozen
engineers and a similar number of technicians for a
meeting to launch his transistor development team [see
photos, “Team
Leader”]. According to two of his
lieutenants, Eugene Anderson and Robert Ryder, Morton
already seemed to anticipate that their work would make
history: “We shall change the world,” he prophesied. “In
what manner I do not know, but change it we will.”
The team attacked the noise and reliability problems
on several fronts, and by mid-1949 they had two improved
versions ready for production, one to amplify signals
and the other for switching applications. Western
Electric began manufacturing the transistors in 1950,
and Bell System engineers soon found uses for them. The
first commercial application was in a tone generator
used in toll-call signaling.
Morton also had the foresight to pursue what became
known as “fundamental development” of basic
manufacturing processes and technologies that could have
across-the-board implications for the new semiconductor
industry. A prime example: when the chemist Gordon Teal
could not convince his own department head to let him
grow large single crystals of germanium for use in
making transistors, he appealed to Morton for support.
Coming from electron tube manufacturing, Morton
understood that transistor action demanded a
near-perfect medium—like the vacuum in a tube—and so
he readily came up with the pittance required to buy or
build the necessary crystal-growing equipment. Dollar
for dollar, it was probably the best investment in Bell
Labs’ history.
Morton knew how to get research ideas and designs out
of the Labs and into manufacturing at Western Electric,
too. Here the groundwork had been laid by his mentor,
Kelly, who during the war had recognized the obstacles
to transferring technology from an isolated central lab.
He felt it was crucial to have people familiar with the
latest scientific and technological advances working
right on the shop floor, especially when fabricating
high-tech components. And so, after 1945 he established
a system of branch labs at several Western Electric
plants, consisting of teams of Bell Labs employees
focused on production engineering and acting as liaison
with their colleagues back in Murray Hill.
Morton fine-tuned this approach at the new Western
Electric plant in Allentown, Pa., which produced
electronic devices and components for the Bell System.
He set up a semiconductor development group there and
put Anderson in charge. A tube engineer who had been
with Morton’s Murray Hill transistor team from the
outset, Anderson had a good grasp of the necessary
solid-state physics and semiconductor technology.
So Morton’s development team was poised to move
quickly in mid-1951 when Bell Labs announced the
successful fabrication of the junction transistor, much
more rugged and practical than the delicate
point-contact device invented by Bardeen and Brattain.
Conceived by Shockley and fashioned by chemist Morgan
Sparks using Teal’s crystal-growing apparatus, this
three-layer germanium sandwich had a much simpler
structure than the point-contact transistor and far
outperformed it. That the junction transistor would be
the preferred path to commercialization was immediately
obvious. And Morton’s group led the way, getting the
device into production within a year.
In the
beginning, transistors were made of
germanium, not silicon. Although germanium’s lower
melting point makes it far easier to purify, transistors
crafted from it are sensitive to temperature changes.
And they make lousy switches: tiny leakage currents
continue to flow even when the devices are nominally
off. Silicon doesn’t have these problems, but it’s a lot
more difficult to work with. In the early 1950s, only a
few farsighted researchers like Shockley recognized that
silicon was the semiconductor material of the future.
In 1954 Morris Tanenbaum fabricated the first silicon
transistor at Bell Labs [see “The Lost History of the
Transistor,” IEEE Spectrum, May 2004]. Later that year
AT&T executives decided to pursue the first
electronic switching system—known as ESS‑1—based on
semiconductor devices rather than electromechanical
crossbar switches. A trial run was set to begin in 1958.
Morton faced a crucial decision: whether to employ the
(by then) well-established germanium technology or bet
the house on silicon, which still had a long way to go
in development and was thus far riskier. Both Sparks and
Tanenbaum, who worked on the research side of the fence
and didn’t have to worry about manufacturing devices of
extreme reliability, now say in hindsight that the
choice to go with silicon was obvious. At the time,
however, it was anything but.
In March 1955 Tanenbaum improved on his earlier
invention by diffusing impurities into the silicon. This
process allowed him to fashion a narrow base layer—the
“meat” in the semiconductor sandwich—only about a
micrometer thick. The device, which came to be known as
a diffused-base transistor, could amplify and switch
signals above 100 megahertz, into the range of FM radio
and television. Best of all, such a high switching
speed, about 10 times that of previous silicon
transistors, meant that it could be used for electronic
switching.
When he heard the news, Morton was in Europe. He
immediately canceled his travel plans and rushed back to
Allentown. “On a snowy, miserable day,” recalled
Anderson, Morton decreed that “it was to be in silicon
as a material and diffusion as a technology that future
transistor and diode development would move in the Bell System.”
His bold decision proved correct. Bell Labs
researchers soon resolved the difficulties with
purifying silicon and growing crystals of it. They then
discovered how to make a glassy, protective oxide layer
on the silicon surface that could be used to pattern the
impurity diffusions. Fairchild Semiconductor Corp., in
Mountain View, Calif., led by Robert Noyce, would adapt
these silicon technologies to produce the first
commercial microchips in 1961. Western Electric, in
turn, used Fairchild’s patented planar process to make
diffused-base silicon transistors for the Bell System’s
ESS-1, which began to show up in phone exchanges in the
early 1960s [see photo, “From
Lab to Factory”]. Kelly’s dream of
electronic switching finally became reality, thanks in
part to Morton’s courage and vision.