|
May 1969 Radio-Electronics
 [Table of Contents]
Wax nostalgic about and learn from the history of early electronics.
See articles from Radio-Electronics,
published 1930-1988. All copyrights hereby acknowledged.
|
Breaking news from May 1969:
Researchers at Bell Labs and Japan's Kyodo Electronic Labs developed new IC fabrication
methods to cut costs and shrink transistor sizes by 75%. Bell's collector-diffusion
isolation eliminates masking steps by using a p-type layer for insulation, while
base-diffusion isolation reduces power needs and enables sub-1-nsec switching. Kyodo's
technique deposits insulating polycrystalline silicon oxide, allowing denser circuits.
These advances could double or triple IC yields per silicon wafer. Meanwhile, Hughes
Aircraft tested retractable solar arrays for spacecraft, delivering 1,500 watts
when unfurled. In consumer tech, Motorola introduced a 20-cent audio amplifier IC,
aiming to mass-produce cheap chips for Asian markets. Japan planned to challenge
U.S. dominance in color TVs, targeting 6.8 million sets by 1970. A new gadolinium-oxide
phosphor promised 32% brighter color tubes, paired with hexagonal shadow masks.
New & Timely
 New Fabrication Methods to Cut IC Cost and
Size
Although fabrication of monolithic integrated circuits has been somewhat standardized
for mass production, the process is still complex and costly. But now independent
research by scientists at Bell Labs and Japan's Kyodo Electronic Labs has simplified
fabrication, eliminating up to three masking steps, reducing transistor areas on
the chip 75% and making switching times less than 1 nsec possible.
A disadvantage to conventional IC fabrication methods is the separate masking
process required to electrically isolate chip components. In this diffusion isolation
method (top drawing), p-type material is spread through the n-type layer to form
a p-n junction with the p substrate. The diode property of this junction acts as
an insulator.
One of the new techniques, proposed a year ago by Bell and now tested, uses a
p-type layer grown on the p-substrate. Called collector-diffusion isolation, the
process achieves several things in one strongly doped n-type diffusion step: collector-contact
areas are established that also serve as isolating regions, and transistors bases
and resistances are formed. Two masking operations can be eliminated and transistor
area needs are quartered. IC's made with this method are suitable for moderate speed
and power applications.
A second method, called base-diffusion isolation, uses a narrow p-type ring diffused
around the transistor when its base is built up. Negative bias on the ring isolates
the n-type region. Very low power is necessary, but transistor area is 3/4% less
than with conventional IC's and an optional buried collector offers below 1 nsec
switching.
The Kyodo isolation technique involves depositing a polycrystalline layer such
as silicon oxide where needed on the substrate. When the n-type layer is grown on
the substrate slice, it forms an insulating polycrystalline layer above the oxide
deposits, but a normal-conducting single crystal where circuit elements are fabricated.
When incorporated into IC production lines, the new methods should reduce costs.
Two to three as many circuits fit on a silicon slice than with standard IC circuits.
 Huge retractable solar array panels that
can be carried into space rolled up like a window shade are being developed for
tests late next year. When unfurled in space, the 5 1/2 x 16-foot panels could deliver
1500 watts of power for orbiting satellites and interplanetary spacecraft.
When a spacecraft maneuvers in orbit or passes through radiation belts, the panels
can be rolled up for storage on their drums. The T-shaped mechanism on which the
array will be mounted keeps the silicon solar cells perpendicular to the sun line.
Units for the system being built by Hughes Aircraft Co. for the Air Force provide
for energy storage, power control and sun tracking. Power output of the panels is
28 volts at 54 amperes.
By David Lachenbruch, Contributing Editor
Bright Idea
Goodbye Yttrium - Hello Gadolinium!
This might be the hit song from the upcoming color TV saga, "The Battle of the
Rare Earths," as the color tube brightness war stands on the brink of a new escalation
for manufacturers.
At least one manufacturer is planning a new super-bright tube, keyed to the use
of the rare earth gadolinium and a new shadow-mask. The combination could result
in another brightness step-up of about 32%. Most color tubes now use a red phosphor
formulated from either europium-activated yttrium vanadate or europium-activated
yttrium oxide. The new phosphor, now being produced by two chemical firms, is based
on europium-activated gadolinium oxide, and is claimed to add a brightness factor
of about 20% to the red color.
The rest of the brightness increase will be gained by using a new shadow-mask
with hexagonal holes which are slightly larger than the round holes in current masks.
(R-E, August 1968).
Consumer IC Breakthrough?
The spread of integrated circuits in consumer products has been slower than expected,
with monolithic chips generally showing up only in higher-priced products because
of their high costs - an average of a dollar each in large quantities.
This could begin to change rapidly. Now in production is the forerunner of a
line of consumer ICs designed to sell in manufacturer quantities at-would you believe
20 cents?
The IC in question is a plastic quarter-watt audio amplifier designed for radio
and TV, being built by Motorola, which says it could turn out more than a million
weekly by year's end. Coming later will be versions for i.f. strips in AM and PM
sets. So certain is Motorola that it can break the IC price barrier that it plans
to ship the units in huge quantities to manufacturers in Japan, Hong Kong and Taiwan,
and eventually produce them in its own plant in South Korea.
Other semiconductor manufacturers are working on low-cost plastic ICs for everyday
consumer electronics use, too, and the true microcircuit age for low-cost products
could begin early next year.
Who's Ahead?
Japan, which took over from the United States as the largest producer of radios,
now says it's ready to challenge us in color TV. The Ministry of International Trade
and Industry there says that by 1970 Japan could be the world's largest supplier
of color sets. Current expansion plans will increase its total manufacturing capacity
to nearly 6.8 million sets next year, although it made only 2.7 million last year
and is preparing to turn out 4 million in 1969. American manufacturers made nearly
6 million color sets last year, expect to make about 10% more this year.
|
