Featured Research

from universities, journals, and other organizations

UNC-CH Scientists Observe For First Time How Bonds Behave At High Temperatures

Date:
January 28, 1998
Source:
University Of North Carolina At Chapel Hill
Summary:
Using a sophisticated device known as a scanning tunneling microscope, chemists at the University of North Carolina at Chapel Hill for the first time have observed directly how hydrogen atoms behave and bond to surfaces at high temperatures.

CHAPEL HILL -- Using a sophisticated device known as a scanning tunneling microscope, chemists at the University of North Carolina at Chapel Hill for the first time have observed directly how hydrogen atoms behave and bond to surfaces at high temperatures.

What the scientists have seen is a form of atomic Ping-Pong in which hydrogen atoms unpair, hop back and forth on the surface of silicon and sometimes even exchange partners. Their work is important, they say, because it helps explain what happens during silicon growth and related processes central to microelectronics manufacturing and other industries.

One of the chemists, Dr. John J. Boland, an associate professor, likened the reactions to a high school romance. "These pairs are constantly splitting up and getting back together," Boland said. "Occasionally, a third party comes along, and a new pair is formed."

A report on the findings appears in the Jan. 23 issue of the journal Science. Besides Boland, authors of the paper, also in chemistry at UNC-CH, are postdoctoral fellow Dr. Marc McEllistrem and graduate student Matthew Allgeier.

The research involved bombarding with deuterium, or "heavy" hydrogen atoms, tiny samples of silicon in a vacuum chamber so that hydrogen atoms covered the silicon surface and filled in almost all reactive sites known as dangling bonds. Chemists then photographed every 15 seconds what happened on the silicon surface after they heated it to about 650 degrees Fahrenheit.

The surprise was that the remaining dangling bonds on the surface, which were initially paired, unpaired and efficiently re-paired multiple times, depending on the temperature.

"This unpairing and re-pairing behavior, which was unknown before, is good news because it shows favorable conditions for growing more silicon," McEllistrem said. "This could mean future computer chips that would work faster."

"What we have done doesn't fully explain what is going on at the atomic level, but it is an important part of the picture," Boland said. "There is no reason why it would not apply to many other materials besides silicon."

Reactions of the kind the UNC-CH scientists studied are important in a common growth process known as chemical vapor deposition, he said. Growing industrial diamonds and coating engine parts, for example, are achieved using this process, except with different atoms.

"The new work also helps explain why growth of solids may not occur even under conditions where dangling bones are available," Boland said.

"One of the especially fun things about this technique is that you can actually see the atoms and watch the chemistry in progress by seeing how the pictures evolve over time," McEllistrem said.

The UNC-CH research was supported by the National Science Foundation.


Story Source:

The above story is based on materials provided by University Of North Carolina At Chapel Hill. Note: Materials may be edited for content and length.


Cite This Page:

University Of North Carolina At Chapel Hill. "UNC-CH Scientists Observe For First Time How Bonds Behave At High Temperatures." ScienceDaily. ScienceDaily, 28 January 1998. <www.sciencedaily.com/releases/1998/01/980128073851.htm>.
University Of North Carolina At Chapel Hill. (1998, January 28). UNC-CH Scientists Observe For First Time How Bonds Behave At High Temperatures. ScienceDaily. Retrieved September 23, 2014 from www.sciencedaily.com/releases/1998/01/980128073851.htm
University Of North Carolina At Chapel Hill. "UNC-CH Scientists Observe For First Time How Bonds Behave At High Temperatures." ScienceDaily. www.sciencedaily.com/releases/1998/01/980128073851.htm (accessed September 23, 2014).

Share This



More Matter & Energy News

Tuesday, September 23, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Company Copies Keys From Photos

Company Copies Keys From Photos

Newsy (Sep. 22, 2014) A new company allows customers to make copies of keys by simply uploading a couple of photos. But could it also be great for thieves? Video provided by Newsy
Powered by NewsLook.com
Rockefeller Oil Heirs Switching To Clean Energy

Rockefeller Oil Heirs Switching To Clean Energy

Newsy (Sep. 22, 2014) The Rockefellers — heirs to an oil fortune that made the family name a symbol of American wealth — are switching from fossil fuels to clean energy. Video provided by Newsy
Powered by NewsLook.com
Raw: SpaceX Rocket Carries 3-D Printer to Space

Raw: SpaceX Rocket Carries 3-D Printer to Space

AP (Sep. 22, 2014) A SpaceX Rocket launched from Cape Canaveral, carrying a custom-built 3-D printer into space. NASA envisions astronauts one day using the printer to make their own spare parts. (Sept. 22) Video provided by AP
Powered by NewsLook.com
Inside London's Massive Sewer Tunnel Project

Inside London's Massive Sewer Tunnel Project

AP (Sep. 22, 2014) Billions of dollars are being spent on a massive super sewer to take away London's vast output of waste, which is endangering the River Thames. (Sept. 22) Video provided by AP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:

Strange & Offbeat Stories


Space & Time

Matter & Energy

Computers & Math

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins