Featured Research

from universities, journals, and other organizations

New microscope sees what others can't

Date:
May 8, 2014
Source:
National Institute of Standards and Technology (NIST)
Summary:
Microscopes don't exactly lie, but they have limitations. Scanning electron microscopes can't see electrical insulators, and their high energies can actually damage some types of samples. Researchers have now built the first low-energy focused ion beam (FIB) microscope using lithium. The team's new approach opens up the possibility of creating a whole category of FIBs using any one of up to 20 different elements, greatly increasing the options for imaging, sculpting or characterizing materials.

Micrographs of a spot of electronics solder demonstrate how the lithium FIB microscope (left) clearly distinguishes between the lead and tin components. An SEM image (right) captures mainly topological differences. Images show a region approximately 28 micrometers across.
Credit: Twedt/CNST

Microscopes don't exactly lie, but their limitations affect the truths they can tell. For example, scanning electron microscopes (SEMs) simply can't see materials that don't conduct electricity very well, and their high energies can actually damage some types of samples.

Related Articles


In an effort to extract a little more truth from the world of nanomaterials and nanostructures, researchers at the National Institute of Standards and Technology (NIST) have built the first low-energy focused ion beam (FIB) microscope that uses a lithium ion source.

The team's new approach opens up the possibility of creating a whole category of FIBs using any one of up to 20 different elements, greatly increasing the options for imaging, sculpting, or characterizing materials.

Although the new microscope's resolution isn't yet as good as a SEM or a helium ion microscope (HIM), it can image nonconductive materials and can more clearly visualize the chemical composition on the surface of a sample than the higher-energy SEMs and FIBs. And, by analyzing the energy with which the ions scatter, the researchers have shown that the microscope should be able to not only see that adjacent materials are chemically different, but also identify the elements that make them up.

Jabez McClelland and his colleagues at NIST applied Nobel Prize-winning laser cooling techniques to make the first low-energy FIB using lithium ions in 2011. Since then, they have been working to refine the technique to increase the beam's brightness and collimation, i.e., getting all the ions to move in the same direction to make it more useful for imaging applications.

The new instrument first cools a gas of neutral lithium atoms to a temperature of about 600 microkelvins, just a few millionths of a degree above absolute zero, using lasers and a magneto-optical trap (MOT) to hold the atoms. Another laser ionizes the atoms and then electric fields accelerate them, straightening out their flight and focusing the beam on a target.

The NIST FIB can produce lithium ion beams with energies in the range of 500 electron volts to 5,000 electron volts (compared to about30,000 electron volts for HIMs.) The NIST team can reduce the beam's energy even further, but repulsive interaction effects at the source limit how small they can focus the beam when the accelerating field is weaker.

As detailed in their paper, the team demonstrated how their microscope could help to solve a common problem in nanoimprint lithography, a process for stenciling patterns on silicon chips. This technique requires etching into the silicon through the spaces in the lithography stencil to transfer the pattern.

"Before manufacturers can etch the silicon, they have to make sure the spaces are free of chemical residue," says McClelland. "Commonly, they use a process called plasma etching to clean that residue off, but they have to be careful not to overdo it or they can damage the substrate and ruin the chip. Our FIB scope could check to see if the plasma has done its work without damaging the chip. A scanning electron microscope couldn't do this because it's difficult to see the thin residue, and the high-energy beam is likely to charge up and/or melt the stencil and make the problem worse."

The group has big plans for the microscope. One future project they're planning to do is trying to unravel exactly how lithium batteries work by injecting lithium ions into the materials and watching how they affect the behavior of the batteries. This and other applications will add to the capabilities of NIST's nanotechnology user facility, the Center for Nanoscale Science and Technology, where the work is being carried out.

A few former members of the group have started their own company to develop a low-energy cesium FIB for milling and sculpting features on the order of single nanometers, a huge leap in nanofabrication if successful.

"This new form of microscopy we've developed promises to provide a new tool for nanotechnology with good surface sensitivity, elemental contrast and high resolution," says McClelland. "The applications range from nanofabrication process control to nanomaterial development and imaging of biomaterials."


Story Source:

The above story is based on materials provided by National Institute of Standards and Technology (NIST). Note: Materials may be edited for content and length.


Journal Reference:

  1. Kevin A. Twedt, Lei Chen, Jabez J. McClelland. Scanning ion microscopy with low energy lithium ions. Ultramicroscopy, 2014; 142: 24 DOI: 10.1016/j.ultramic.2014.03.014

Cite This Page:

National Institute of Standards and Technology (NIST). "New microscope sees what others can't." ScienceDaily. ScienceDaily, 8 May 2014. <www.sciencedaily.com/releases/2014/05/140508121459.htm>.
National Institute of Standards and Technology (NIST). (2014, May 8). New microscope sees what others can't. ScienceDaily. Retrieved October 24, 2014 from www.sciencedaily.com/releases/2014/05/140508121459.htm
National Institute of Standards and Technology (NIST). "New microscope sees what others can't." ScienceDaily. www.sciencedaily.com/releases/2014/05/140508121459.htm (accessed October 24, 2014).

Share This



More Matter & Energy News

Friday, October 24, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

3D Printed Instruments Make Sweet Music in Sweden

3D Printed Instruments Make Sweet Music in Sweden

Reuters - Innovations Video Online (Oct. 23, 2014) Students from Lund University's Malmo Academy of Music are believed to be the world's first band to all use 3D printed instruments. The guitar, bass guitar, keyboard and drums were built by Olaf Diegel, professor of product development, who says 3D printing allows musicians to design an instrument to their exact specifications. Matthew Stock reports. Video provided by Reuters
Powered by NewsLook.com
Chameleon Camouflage to Give Tanks Cloaking Capabilities

Chameleon Camouflage to Give Tanks Cloaking Capabilities

Reuters - Innovations Video Online (Oct. 22, 2014) Inspired by the way a chameleon changes its colour to disguise itself; scientists in Poland want to replace traditional camouflage paint with thousands of electrochromic plates that will continuously change colour to blend with its surroundings. The first PL-01 concept tank prototype will be tested within a few years, with scientists predicting that a similar technology could even be woven into the fabric of a soldiers' clothing making them virtually invisible to the naked eye. Matthew Stock reports. Video provided by Reuters
Powered by NewsLook.com
Jet Sales Lift Boeing Profit 18 Pct.

Jet Sales Lift Boeing Profit 18 Pct.

Reuters - Business Video Online (Oct. 22, 2014) Strong jet demand has pushed Boeing to raise its profit forecast for the third time, but analysts were disappointed by its small cash flow. Fred Katayama reports. Video provided by Reuters
Powered by NewsLook.com
Internet of Things Aims to Smarten Your Life

Internet of Things Aims to Smarten Your Life

AP (Oct. 22, 2014) As more and more Bluetooth-enabled devices are reaching consumers, developers are busy connecting them together as part of the Internet of Things. (Oct. 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