IEEE Spectrum October, 2016 - 52

1958
Jack Kilby starts
at Texas Instruments (TI) and
develops a
prototype integrated circuit.

oct 2016

North AmericAN

1967
Kilby and TI
colleagues file
a patent for the
world's first
handheld
calculator.

1970
Kilby takes a
leave of absence
from TI to work as
an independent
inventor.

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ufacturer, and defense supplier, had
roots in all three of those industries.
Kilby's system differed from most
other solar technologies in that it
answered the eternal question, What
do you do when the sun's not shining?
Because the system stored the chemical constituents separately and combined them on demand, the moment
when photons struck could be temporally separated from the moment
when the system created electricity.
Kilby and his colleagues also believed
that their system would be considerably easier to manufacture than other
silicon-based solar energy schemes.
At the time, fabricating large sheets
of single-crystal silicon for photovoltaic cells was difficult and expensive.
But Kilby's liquid-fuel system used
silicon pellets with less-exacting qualities. the tiny spheres could be produced using a method invented in
the late 18th century to make shotgun pellets. In this fiendishly simple
technique, molten lead (or silicon) is
poured from the top of a "shot tower,"
forming spherical droplets that cool
and solidify as they fall.

y The spring of 1975, Kilby was ready
to present the idea to tI. for
once, he got a positive response.
tI agreed to shepherd Kilby, Lathrop,
and Porter's invention through the
u.s. patent office and to seek patents
in dozens of other countries, too. the
firm also provided Kilby and his colleagues with generous research funding, and it formed its own development
team, code-named Project Illinois after
Kilby's alma mater. As the use of a code
name implies, tI wasn't yet ready to go
public with the project. this way, the
firm could take advantage of Kilby's
leave of absence. he could attend solar
power conferences and approach fed-

1973
Kilby proposes that he and Jay
Lathrop, a former TI colleague,
begin thinking about ways to
lessen the dependence on oil.
They soon acquire a third
collaborator, W. Arthur "Skip" Porter.

Previous Page and above: Texas insTrumenTs records/
degolyer library/souThern meThodisT universiTy

rator, A&m's W. Arthur "skip" Porter,
bears strong similarities in aesthetics,
and the three came up with a basic idea
operation, and objectives to tI's later,
for a residential solar energy system.
wildly successful speak & spell line of
At its core, it consisted of a set of very
computers for children. But while the
shallow tubes partially filled with fluid-
speak & spell broke new ground in dighydrogen bromide in most of the conital signal processing and electronic
figurations they discussed. Lining the
voice synthesis, Kilby's machine did not.
bottom of each tube were thousands of
Kilby was also interested in higher
silicon spheres the size of BB-gun peleducation. throughout the 1970s,
lets, embedded in a translucent matrix.
he worked with electrical engineers
solar photons would strike those silicon
at texas A&m university and with
pellets and knock off electrons, creating
Jay Lathrop, a former tI colleague at
an electric potential that would break
Clemson university, in south Carolina,
down the fluid around them into hydroto develop new ways to teach undergen and bromine. these constituents
graduates the practice of integrated cirwould be siphoned off
cuit design and fabrication
and stored until elecso as to better ready them
tricity was needed,
for industry.
at which point they
In late 1973, however,
would be recombined
Kilby and Lathrop's corin a fuel cell and then
respondence suddenly
circulated back into
turned away from discusthe tubes.
sions of syllabi, textbooks,
Kilby, Lathrop, and
and course requirements.
Porter weren't alone
the organization of Arab
in entering the solar
Petroleum exporting Counfield
in the wake of
tries embargo on oil exports
Cells of siliCon: The
the oil embargo. the
and soaring oil prices dom- heart of the solar generation system that Kilby and
1970s saw a boom in
inated the headlines, and
his colleagues developed
solar energy. from
Kilby proposed that he and
consisted of small pieces
1974 to 1979, federal
Lathrop think about how
of silicon embedded in
translucent material.
funding for renewto apply their expertise in
able energy develsilicon to lessen the world
opment rose from us $32 million per
economy's dependence on oil. (At the
year to $1.36 billion. Private-sector
time, the united states used oil not
interest mirrored this growth. By 1976,
only to heat homes and to refine into
Solar Engineering Magazine listed 88
gasoline but also to generate a sizable
companies with some involvement
fraction of its electricity.) Lathrop readin solar energy that were traded on
ily agreed. In taking this detour, the
the new York stock exchange. those
two men displayed a remarkable spirit
large companies were joined by small
for reinvention: they both jumped
firms, academic laboratories, and amainto new careers and would reinvent
teur enthusiasts. oil, electronics, and
themselves as students-and eventumilitary-industrial firms were all heavally experts-in the physics, chemistry,
ily involved in solar in the 1970s. texas
and economics of solar energy.
Instruments, as an oil-field instrumenWithin a few months Kilby and
tation company, semiconductor manLathrop had acquired a third collabo-

1973
President Richard Nixon
announces Project Independence, an ambitious
plan to make the United
States energy independent by 1980.

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Table of Contents for the Digital Edition of IEEE Spectrum October, 2016