Featured Research

from universities, journals, and other organizations

Semiconductor interfaces: Big opportunities for tiny insulators

Date:
February 13, 2013
Source:
The Agency for Science, Technology and Research (A*STAR)
Summary:
A model that predicts real-world behaviors of insulator interfaces makes designing ‘nano-electronic’ materials significantly simpler.

A new theoretical model enables accurate predictions of dipoles at oxide interfaces (left, electron microscopy image) using the classical property of electronegativity (right). The scale shows how two elements with different relative electronegativities align at an interface.
Credit: © 2013 A*STAR Institute of Materials Research and Engineering

A model that predicts real-world behaviors of insulator interfaces makes designing 'nano-electronic' materials significantly simpler.

Advances in miniaturization have made electronic devices cheaper and more powerful, but these procedures also create new challenges for materials scientists. For example, traditional silicon dioxide insulators used in field-effect transistors begin to leak small amounts of current at nanoscale dimensions. To combat this problem, researchers have developed insulators called 'high-k dielectrics' that link heavier elements, such as hafnium or zirconium, into insulating oxide films with exceptional charge-isolating capabilities.

Integrating high-k dielectrics into circuits, however, creates a different manufacturing problem. Localized electric fields known as charged dipoles can form at insulator-semiconductor interfaces and generate unwanted voltages that impact device performance. Sing Yang Chiam from the A*STAR Institute of Materials Research and Engineering in Singapore and co-workers have now developed a model that can identify interface dipole problems before they appear1 -- a finding that promises to help end the 'trial-and-error' design issues typical of high-k dielectrics.

Currently, materials scientists employ extensive quantum mechanical calculations to determine whether or not new high-k dielectrics will have interface dipoles. Chiam and co-workers investigated a more intuitive approach: they linked the appearance of interface dipoles to the classical property of electronegativity, a number that relates an element's electron-attracting power to its position in the periodic table.

Scientists have previously avoided estimating dipoles with electronegativity values because, in many cases, they predict incorrect electric field polarities. To resolve this discrepancy, Chiam and co-workers correlated theoretical electronegativity with experimental 'charge neutrality levels' -- electronic energies required to counterbalance dipoles on insulator interfaces. After measuring the charge neutrality on several different high-k dielectrics with X-ray and ultraviolet radiation (see image), the team plotted this data against electronegativity. They discovered that a simple linear equation connected the two parameters.

Further manipulation of this equation revealed it could also predict a so-called 'dipole neutrality point' (DNP) where interfacial dipoles flip polarity. Armed with this new theoretical tool, the researchers investigated both well-known and novel high-k dielectric/semiconductor interfaces. They found that the DNP concept provided accurate predictions of dipole polarity and strength: the offset voltages needed to turn on a high-k dielectric field-effect transistor closely matched values generated from the electronegativity values.

Chiam notes that the straightforwardness of this model should make it exceptionally practical for scientific discovery. "This is the simplest method to find dipoles at material interfaces before starting experiments," he says. "Our model can predict what kinds of bulk or interface modifications are needed to offset dipole values -- a significant time saving over traditional approaches."

The A*STAR-affiliated researchers contributing to this research are from the Institute of Materials Research and Engineering


Story Source:

The above story is based on materials provided by The Agency for Science, Technology and Research (A*STAR). Note: Materials may be edited for content and length.


Journal Reference:

  1. Z. Q. Liu, W. K. Chim, S. Y. Chiam, J. S. Pan, C. M. Ng. An interface dipole predictive model for high-k dielectric/semiconductor heterostructures using the concept of the dipole neutrality point. Journal of Materials Chemistry, 2012; 22 (34): 17887 DOI: 10.1039/C2JM32589F

Cite This Page:

The Agency for Science, Technology and Research (A*STAR). "Semiconductor interfaces: Big opportunities for tiny insulators." ScienceDaily. ScienceDaily, 13 February 2013. <www.sciencedaily.com/releases/2013/02/130213173039.htm>.
The Agency for Science, Technology and Research (A*STAR). (2013, February 13). Semiconductor interfaces: Big opportunities for tiny insulators. ScienceDaily. Retrieved September 16, 2014 from www.sciencedaily.com/releases/2013/02/130213173039.htm
The Agency for Science, Technology and Research (A*STAR). "Semiconductor interfaces: Big opportunities for tiny insulators." ScienceDaily. www.sciencedaily.com/releases/2013/02/130213173039.htm (accessed September 16, 2014).

Share This



More Matter & Energy News

Tuesday, September 16, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Manufacturer Prints 3-D Car In Record Time

Manufacturer Prints 3-D Car In Record Time

Newsy (Sep. 15, 2014) — Automobile manufacturer Local Motors created a drivable electric car using a 3-D printer. Printing the body only took 44 hours. Video provided by Newsy
Powered by NewsLook.com
Refurbished New York Subway Tunnel Unveiled After Sandy Damage

Refurbished New York Subway Tunnel Unveiled After Sandy Damage

Reuters - US Online Video (Sep. 15, 2014) — New York officials unveil subway tunnels that were refurbished after Superstorm Sandy. Nathan Frandino reports. Video provided by Reuters
Powered by NewsLook.com
Frustration As Drone Industry Outpaces Regulation In U.S.

Frustration As Drone Industry Outpaces Regulation In U.S.

Newsy (Sep. 14, 2014) — U.S. firms worry they’re falling behind in the marketplace as the FAA considers how to regulate commercial drones. Video provided by Newsy
Powered by NewsLook.com
Smart Gun Innovators Fear Backlash From Gun Rights Advocates

Smart Gun Innovators Fear Backlash From Gun Rights Advocates

Newsy (Sep. 14, 2014) — Winners of a contest for smart gun design are asking not to be named after others in the industry received threats for marketing similar products. Video provided by Newsy
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:
from the past week

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