Featured Research

from universities, journals, and other organizations

Microscope probe-sharpening technique improves resolution, durability

Date:
July 6, 2012
Source:
University of Illinois at Urbana-Champaign
Summary:
A simple new improvement to an essential microscope component could greatly improve imaging for researchers who study the very small, from cells to computer chips. Researchers developed a technique to sharpen microscope probes, giving images much higher resolution, and a coating to make the probes durable.

A traditionally etched tungsten STM probe (left), sharpened to a 1-nanometer point after bombarding it with ions (right).
Credit: Image courtesy Joseph Lyding

A simple new improvement to an essential microscope component could greatly improve imaging for researchers who study the very small, from cells to computer chips.

Related Articles


Joseph Lyding, a professor of electrical and computer engineering at the University of Illinois, led a group that developed a new microscope probe-sharpening technique. The technique is described in research published this week in the journal Nature Communications.

Scanning probe microscopes provide images of tiny structures with high resolution at the atomic scale. The tip of the probe skims the surface of a sample to measure mechanical, electrical or chemical properties. Such microscopes are widely used among researchers who work with tiny structures in fields from nanotechnology to cellular biology.

Labs can spend hundreds of thousands of dollars on an elegant instrument -- for example, a scanning tunneling microscope (STM) or an atomic force microscope (AFM) -- yet the quality of the data depends on the probe. Probes can degrade rapidly with use, wearing down and losing resolution. In such cases, the researcher then has to stop the scan and replace the tip.

"To put it in perspective, if you had an expensive racecar but you put bicycle tires on it, it wouldn't be a very good car," Lyding said.

To shape tips, researchers shoot a stream of ions at the tip. The material sputters off as the ions collide with the tip, whittling away the probe. One day in the lab, after yet another tip failure, Lyding had the simple, novel idea of applying a matching voltage to the tip to deflect the incoming ions. When a voltage is applied to a sharp object, the electrical field gets stronger as the point narrows. Therefore, ions approaching the sharpest part of the electrified tip are deflected the most.

"This causes the ions to remove the material around that sharp part, not on the sharp part itself, and that makes it sharper," Lyding said. "You preserve the point and you sharpen what's around it."

Lyding and graduate student Scott Schmucker purchased an inexpensive ion gun and tested Lyding's idea. It worked beautifully. STM tips with a starting radius of 100 nanometers were honed to a sharp 1-nanometer point, yielding extremely high resolution. In addition, the sputtering process works with any electrically conductive material.

But once the probes are ultra-sharp, what's to keep them from wearing down just as quickly as other probes? Lyding and Schmucker then teamed with U. of I. chemistry professor Gregory Girolami and materials science and engineering professor John Abelson, whose groups had demonstrated coatings for silicon semiconductors made of a material called hafnium diboride. The coatings are 10 times harder than the metal usually used to make STM tips, but are also metallic -- the key property for the ion-sputtering process.

The group applied the hafnium diboride coatings to their probes, sputtered them further, and found that the resulting probes are stable, durable and excel in the types of microscopy and patterning applications for which such tips are used.

"Nobody else makes probes with the combination of sharp, hard and metallic conduction," said Lyding, who is also affiliated with the Beckman Institute for Advanced Science and Technology at the U. of I. "You can find one or the other but not all three. There's a tremendous demand for that."

The researchers now are moving to commercialize their tough, sharp probes. They received a patent and started a company called Tiptek to begin manufacture. They are also expanding their sharpening technique to include AFM probes as well as STM, and are developing batch-processing techniques for higher throughput.

"When people make AFM tips they make them on wafers, hundreds of tips at a time," said Lyding. "The methodology that we're developing lets us process this entire wafer as a unit so all 400 tips would be done at the same time."

The Office of Naval Research, the Defense Advanced Research Project Agency and the National Science Foundation supported this work.


Story Source:

The above story is based on materials provided by University of Illinois at Urbana-Champaign. Note: Materials may be edited for content and length.


Journal Reference:

  1. S.W. Schmucker, N. Kumar, J.R. Abelson, S.R. Daly, G.S. Girolami, M.R. Bischof, D.L. Jaeger, R.F. Reidy, B.P. Gorman, J. Alexander, J.B. Ballard, J.N. Randall, J.W. Lyding. Field-directed sputter sharpening for tailored probe materials and atomic-scale lithography. Nature Communications, 2012; 3: 935 DOI: 10.1038/ncomms1907

Cite This Page:

University of Illinois at Urbana-Champaign. "Microscope probe-sharpening technique improves resolution, durability." ScienceDaily. ScienceDaily, 6 July 2012. <www.sciencedaily.com/releases/2012/07/120706165503.htm>.
University of Illinois at Urbana-Champaign. (2012, July 6). Microscope probe-sharpening technique improves resolution, durability. ScienceDaily. Retrieved December 21, 2014 from www.sciencedaily.com/releases/2012/07/120706165503.htm
University of Illinois at Urbana-Champaign. "Microscope probe-sharpening technique improves resolution, durability." ScienceDaily. www.sciencedaily.com/releases/2012/07/120706165503.htm (accessed December 21, 2014).

Share This


More From ScienceDaily



More Matter & Energy News

Sunday, December 21, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Building Google Into Cars

Building Google Into Cars

Reuters - Business Video Online (Dec. 19, 2014) Google's next Android version could become the standard that'll power your vehicle's entertainment and navigation features, Reuters has learned. Fred Katayama reports. Video provided by Reuters
Powered by NewsLook.com
AP Review: Nikon D750 and GoPro Hero 4

AP Review: Nikon D750 and GoPro Hero 4

AP (Dec. 19, 2014) What to buy an experienced photographer or video shooter? There is some strong gear on the market from Nikon and GoPro. The AP's Ron Harris takes a closer look. (Dec. 19) Video provided by AP
Powered by NewsLook.com
Double-Amputee Becomes First To Move Two Prosthetic Arms With His Mind

Double-Amputee Becomes First To Move Two Prosthetic Arms With His Mind

Buzz60 (Dec. 19, 2014) A double-amputee makes history by becoming the first person to wear and operate two prosthetic arms using only his mind. Jen Markham has the story. Video provided by Buzz60
Powered by NewsLook.com
Navy Unveils Robot Fish

Navy Unveils Robot Fish

Reuters - Light News Video Online (Dec. 18, 2014) The U.S. Navy unveils an underwater device that mimics the movement of a fish. Tara Cleary reports. Video provided by Reuters
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