Nanotechnology Now

Our NanoNews Digest Sponsors

Heifer International

Wikipedia Affiliate Button

Home > News > Nanomechanical memory cell could catapult efforts to improve data storage

September 30th, 2004

Nanomechanical memory cell could catapult efforts to improve data storage

Abstract:
Researchers at the University of Illinois at Urbana-Champaign have developed a technique that uses surface chemistry to make tinier and more effective p-n junctions in silicon-based semiconductors. The method could permit the semiconductor industry to significantly extend the life of current ion-implantation technology for making transistors, thereby avoiding the implementation of difficult and costly alternatives.

Story:

New surface chemistry may extend life of technology for making transistors

Nanomechanical memory cell could catapult efforts to improve data storage

Researchers at the University of Illinois at Urbana-Champaign have developed a technique that uses surface chemistry to make tinier and more effective p-n junctions in silicon-based semiconductors. The method could permit the semiconductor industry to significantly extend the life of current ion-implantation technology for making transistors, thereby avoiding the implementation of difficult and costly alternatives.

To make faster silicon-based transistors, scientists much shrink the active region in p-n junctions while increasing the concentration of electrically active dopant. Currently about 25 nanometers thick, these active regions must decrease to about 10 nanometers, or roughly 40 atoms deep, for next-generation devices.

The conventional process, ion implantation, shoots dopant atoms into a silicon wafer in much the same way that a shotgun sends pellets into a target. To be useful, dopant atoms must lie close to the surface and replace silicon atoms in the crystal structure. In the atomic-scale chaos that accompanies implantation, however, many dopant atoms and silicon atoms end up as interstitials – lodged awkwardly between atoms in the crystal.

Ion implantation also creates defects that damage the crystal in a way that degrades its electrical properties. Heating the wafer – a process called annealing – heals some of the defects and allows more dopant atoms to move into useful crystalline sites. But annealing also has the nasty effect of further diffusing the dopant and deepening the p-n junction.

“We developed a way of using surface chemistry to obtain shallower active regions and enhanced dopant activation simultaneously,” said Edmund Seebauer, a professor of chemical and biomolecular engineering at Illinois. “By modifying the ability of the silicon surface to absorb atoms from the substrate, our technique can control and correct the defects induced during implantation.”

Inside the active region, atoms sitting on lattice sites have bonds to four neighbors, which saturates the bonding capacity of the silicon atoms. Atoms sitting on the surface have fewer neighbors, leading to unused, or “dangling” bonds. Atoms of a gas such as hydrogen, oxygen or nitrogen can saturate the dangling bonds.

“These dangling bonds can also react with interstitial atoms, and remove them from the crystal,” Seebauer said. “The process selectively pulls silicon interstitials to the surface, while leaving active dopant atoms in place. The preferential removal of silicon interstitials is exactly what is needed to both suppress dopant diffusion and increase dopant activation.”

Seebauer and his colleagues – chemical and biomolecular engineering professor Richard Braatz and graduate research assistants Kapil Dev and Charlotte Kwok – use ammonia and other nitrogen-containing gases to saturate some of the dangling bonds and control the ability of the surface to remove interstitials.

“The amount of surface nitrogen compound formed, and therefore the number of dangling bonds that become saturated, can be varied by changing the type of gas and the degree of exposure,” Seebauer said. “As an added benefit, nitrogen compounds are also quite compatible with conventional chip manufacturing processes.”

Through computer simulations and experimental verification, the researchers have shown that “defect engineering” by means of surface chemistry can extend the life of current ion-implantation technology and create smaller, faster electronic devices. Seebauer will present the team’s latest findings at the 51st International Symposium of the AVS Science and Technology Society, to be held Nov. 14-19 in Anaheim, Calif.

Funding was provided by International SEMATECH and the National Science Foundation. The researchers have applied for a patent.


Contact:

James E. Kloeppel
Physical Sciences Editor
217-244-1073
kloeppel@uiuc.edu

Copyright © University of Illinois at Urbana-Champaign

If you have a comment, please us.

Bookmark:
Delicious Digg Newsvine Google Yahoo Reddit Magnoliacom Furl Facebook

Related News Press

Chip Technology

Carbon nanotube optics poised to provide pathway to optical-based quantum cryptography and quantum computing: Researchers are exploring enhanced potential of carbon nanotubes for unique applications June 18th, 2018

Making quantum puddles: Physicists discover how to create the thinnest liquid films ever June 13th, 2018

Leti Presenting Strategic Vision and Hosting a Workshop at SEMICON West: “From Electrons to Photons” Leti Workshop and CEO Media Briefing Set for Tuesday, July 10 in W Hotel, San Francisco June 12th, 2018

Nanometrics Updates Time of Webcast at Stifel 2018 Cross Sector Insight Conference June 12th, 2018

Memory Technology

Tunable diamond string may hold key to quantum memory: A process similar to guitar tuning improves storage time of quantum memory May 24th, 2018

A powerful laser breakthrough: Lehigh research team demonstrates terahertz semiconductor laser with record-high output power May 2nd, 2018

Researchers develop nanoparticle films for high-density data storage: April 3rd, 2018

Design approach developed for important new catalysts for energy conversion and storage: New method could aid in design of pharmaceuticals and optical and data storage materials March 21st, 2018

Nanoelectronics

Leti Presenting Strategic Vision and Hosting a Workshop at SEMICON West: “From Electrons to Photons” Leti Workshop and CEO Media Briefing Set for Tuesday, July 10 in W Hotel, San Francisco June 12th, 2018

Quantum Interference May Be Key to Smaller Insulators: Breakthrough could jumpstart further miniaturization of transistors June 6th, 2018

Building nanomaterials for next-generation computing: Scientists recently developed a blueprint to fabricate new nanoheterostructures using 2D materials June 1st, 2018

Rare element to provide better material for high-speed electronics May 30th, 2018

Discoveries

Collaboration yields discovery of 12-sided silica cages June 20th, 2018

Carbon nanotube optics poised to provide pathway to optical-based quantum cryptography and quantum computing: Researchers are exploring enhanced potential of carbon nanotubes for unique applications June 18th, 2018

Camouflaged nanoparticles used to deliver killer protein to cancer June 17th, 2018

Squeezing light at the nanoscale: Ultra-confined light could detect harmful molecules June 17th, 2018

NanoNews-Digest
The latest news from around the world, FREE



  Premium Products
NanoNews-Custom
Only the news you want to read!
 Learn More
NanoStrategies
Full-service, expert consulting
 Learn More











ASP
Nanotechnology Now Featured Books




NNN

The Hunger Project