Stanford R. Ovshinsky

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Stanford R. Ovshinsky (1923- ) is a self-taught Jewish American-Lithuanian engineer, inventor, and physicist. He has invented amorphous semiconductor materials, which gave rise to a whole new segment of material engineering, aiding in the construction of semiconductors, solar energy, and electric cars. These materials are used in photocopy machines, fax machines and LCD displays.

Ovshinsky was granted numerous patents in the 1970s and '80s for amorphous semiconductor materials.

Contents

[edit] Life

Ovshinsky grew up in Akron, Ohio. A true autodidact, Ovshinsky was forced to drop out of school during the great Depression of the 1930s in order to help support his family. Despite this, he developed into a successful mechanical and electrical engineer. He became a skilled machinist during World War II after which he got his first patent for a two-headed lathe designed to produce two (twin) artillery projectiles at a time on the same machine.

Ovshinsky then shifted his interests towards electrical engineering and the then new field of electronic engineering in the 1950s. He co-founded Energy Conversion Laboratories, Inc. in 1960, with his wife Iris, to continue research into chalcogenides in general as switching materials. After some advances in switching technology circa 1963, Ovshinsky changed the name of the company to Energy Conversion Devices,Inc. (ECD).

In the early days of ECD, Nobel Prize winners were among those who dropped in to talk to Stan and tour his laboratory. William Shockley, co-inventor of the transistor, was a frequent visitor. I.I. Rabi, the inventor of NMR, came by as well as Sir Neville Mott, the world's greatest theorist of electrical conductivity. As consultants, Ovshinsky hired well known academics such as David Turnbull (Harvard University) and Arnold Bienenstock whose international reputations in physics lent luster to ECD's research whenever a news announcement was made about new developments. These announcements appeared on the front pages of The New York Times, The Wall Street Journal, and the covers of magazines,[1] greatly encouraging new investment. Over a period of about 40 years, it is estimated that ECD spent half a billion dollars[2] before any profit was made. However, license fees to ECD are beginning to grow, now that amorphous chalcogenides are used for inexpensive solar cells, and in modified form for CD-RW computer memory disks, and possibly even for RAM chips.[3] ECD also has claims on the profits from the nickel metal hydride batteries that were important in laptop computers and are important inhybrid gas-electric automobiles.[4][5]

Since 1990, Ovshinsky has been a member of Sigma Xi, The Scientific Research Society, along with his wife Iris until her death in August 2006.

Ovshinsky has won prizes[6] for outstanding innovation in the U.S. and Europe. The American Ceramic Society now offers the Ovshinsky Award for scientists in the field of amorphous materials research. Stanford R. Ovshinsky is one of the most prolific inventors in American history. He holds hundreds of patents, which puts him in a league the head of which is Thomas Edison.

[edit] Work

[edit] The Ovitron[tm]

Ovshinsky invented and patented the Ovitron(tm), a hybrid solid state/liquid state device that allowed a small variation in voltage to switch a large current (i.e., a relay). This was a feat that germanium and silicon transistors did not do well as their properties degraded rapidly at the high temperatures produced by high current densities. The Ovitron(tm) was based on thin films of tantalum oxides supported on tantalum wires and immersed in a hermetically sealed polyethylene can filled with an oxidizing electrolyte (sulphuric acid). The US Air Force tried the device in airborne electronics, but although it worked it was judged too prone to catastrophic failure (rupture of the sulphuric acid container) for combat use.

[edit] Chalcogenides

In the early 1960s he had samples of various metallic and semi-metallic chalcogenides produced in bulk to determine if they exhibited electronic switching properties as did the tantalum chalcogenide, tantalum oxide. Noting that on certain chalcogenide glasses an electronic switching "mechanism" could be observed by placing two contact electrodes close together on a smooth surface and establishing a voltage between the electrodes Ovshinsky instructed his materials researcher to determine how to manufacture reproducible thin films of the materials for further testing.

In 1963 ECL obtained a vacuum deposition chamber and began experimentally depositing thin films of glassy (amorphous) chalcogenides on non conducting substrates. Ovshinsky soon proposed that concave surfaces be polished on amorphous graphite pins and then after depositing thin films of selected chalcogenides on the polished surfaces of the pins they, the coated surfaces, could be mated in a quartz tube in which they slip fit. These devices exhibited a reproducible threshold voltage switching of relatively high currents.

[edit] Patents

Stanford R. Ovshinsky ultimately obtained U.S. 3,271,591 (with 33 broad claims), covering switching diodes made from amorphous chalcogen compounds such as tellurium alloys. These have bistable resistivity states and can also be used as electronic memory units. Similar phenomena had been observed earlier[7] by scientists like Alan T. Waterman but not pursued. Bell Telephone Laboratories had also observed similar phenomena, but had not gone forward to the device stage.

The problem that held back large scale usage of the Ovshinsky diode was poor reliability, caused by cracks in the low resistance micro-channel. ECD sold patent cross-licenses to larger electronics companies. One of those, ITT Corporation, obtained U.S. 3,448,302, which covered the solution to the cracking problem. The mutual cross-licensing allowing ECD to get a great deal of funding for further research, because little circuit boards could then be given out free to prospective licensees, to reliably demonstrate the memory device.

[edit] See also

[edit] References

  1. ^ "Making It," Anon., Electronics, Sept. 28, 1970, page 4, and photo of ECD memory on cover.
  2. ^ "Electronics Pioneer Hunts for Profits," by Barnaby Feder, New York Times, July 28, 1987, page 6.
  3. ^ "Next Phase For RAM," by David Lammers, Electronic Engineering Times, June 23, 2003, page 1.
  4. ^ "G.M. Signs Electric Car Battery Deal," by Matthew Wald, New York Times, March 10, 1994, page D4.
  5. ^ Ovonics Collects Big Bucks From Japanese Battery Makers," Anon., Automotive Industry, Dec. 1997, page 9.
  6. ^ "ACS Honors Heroes of Chemistry," Anon., Chemical and Engineering News (Amer. Chem. Soc.), Sept. 4, 2000, page 50.
  7. ^ "Bistable Conductor," Alan T. Waterman, Physical Review, Vol. 21, 1923, page 540.

[edit] Further reading

  • Howard, George S., "Stan Ovshinsky and the Hydrogen Economy", c. 2006 (This biography of Stan Ovshinsky includes a history of all of his companies and an overview of the science behind ECD's most important inventions. The author is a counseling psychologist faculty member at University of Notre Dame.)

[edit] External links

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