January 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.
The term "ovonic" - a fairly unfamiliar word these days - appeared in the
May edition of Radio-Electronics, in an article entitled, "All About Ovonics," just a few
months after this news item ran in the January issue (which I posted last month). Ovonics
of "Ovshinsky" (from
Stanford R. Ovshinsky,
the inventor) and "electronics." Read the "All About Ovonics" article for a
deeper dive into the subject. The big deal, which turned out to be not a big
enough deal, was the use of amorphous "glassy" compounds as semiconductors
rather than the standard crystalline silicon structures. Maybe someday an
enterprising genius inventor type will give a rebirth to the concept.
Glass Semiconductors Developed
A solid-state physics development involving
the switching characteristics of glassy amphorous semiconductors may eventually
bring about a size and price cut in some semiconductors.
Compounds such as oxide- and boron-based glasses and materials that contain tellurium
and chemically similar elements can be made to act electrically like diodes and
magnetic memory cores. Unlike the orderly crystalline structure of semiconductors
that require complex and expensive doping, the glassy materials have a disordered
(amphorous) atomic structure.
Two new switching devices using the materials have been developed and are being
manufactured by Energy Conversion Devices, a Michigan firm. Called the Ovonic Threshold
Switch (OTS) and Ovonic Memory Switch (OMS) by the developer and company president,
Stanford R. Ovshinsky, the devices can switch both alternating current and direct
current equally well. Ordinary semiconductor pn-type junctions have a preferred
Developer of the new devices, Stanford R. Ovshinsky, demonstrates the conducting
state (right) and non-conducting (disordered) state of polymer structures.
When voltage is applied to an CTS, it remains an insulator until a threshold
voltage is reached. It then switches rapidly (150 trillionths of a second) into
conduction and conducts as long as current exceeds a critical value. Depending on
its thickness and composition, threshold voltage may range from about two to several
hundred volts. The OMS is similar, except it remains in its conduction state when
current is removed, and blocks current when a pulse is again applied.
The firm foresees a number of "spectaculars" for the devices, such as flat TV
displays and pocket-size computers. The devices can be produced cheaply in sizes
as small as 0.005 of an inch across.
Posted May 16, 2019