Manufacturing Bits: May 5

Transparent armor
The U.S. Naval Research Laboratory (NRL) has developed transparent armor. The technology is actually a hard transparent ceramic, based on a material called spinel. Spinel is a magnesium aluminate compound. Spinel is also a gemstone, which could come in various colors.

NRL has devised a fabrication process to create the technology, which is harder and superior to glass, sapphire and other materials. Applications include consumer electronics, high energy lasers and transparent armor.

The U.S. Naval Research Laboratory uses a hot press to make spinel into conformable optics (Photo: U.S. Naval Research Laboratory/Jamie Hartman)

Traditionally, spinel has been made using a crucible. “A big problem with growing crystals is that you have to melt the starting powder at very high temperatures, over 2000 degrees Celsius,” said NRL researcher Jas Sanghera on the agency’s Web site. “The molten material reacts with the crucible, and so if you’re trying to make very high quality crystals, you end up [with a] huge amount of defects.”

As a result, NRL researchers use a hot press technique called sintering. This process compacts and forms a solid mass of material by heat and/or pressure. “You put the powder in [a hot press], you press it under vacuum, squash this powder together—and if you can do that right, then you can get rid of all the entrapped air, and all of a sudden it comes out of there clear-looking,” he said.

The hot press is used to transform the spinel powder into transparent solid materials. The method includes a spray-coating process. This, in turn, coats the spinel powder particles with a sintering aid.

The technology could be used in smartphones and smart watches. It could be used as transparent armor for military vehicles and face shields. The military is also interested in using spinel to protect infrared cameras and next-generation lasers.

Atom beam startup
Sematech and Exogenesis will form a new company to bring a next-generation surface modification technology to the semiconductor market.

Located in New York, the new company plans to commercialize Exogenesis’ accelerated neutral atom beam (ANAB) technology. The technology appears to be a form of selective deposition. Combining novel chemistries and tools, selective deposition involves a process of depositing materials and films in exact places.

ANAB is an ion bombardment system. In ANAB, argon gas clusters are ionized and accelerated towards a target. The beams collide and modify the surface, at depths 2nm to 5nm below the structure.

The technology is based on the company’s NanoAccel platform. The platform consists of a gas cluster ion beam (GCIB) technology. Pressurized argon gas forms a beam of gas clusters. Each cluster is comprised of several hundred to a few thousand atoms. The clusters are electrically charged. They are accelerated up to several tens of thousands of volts.

ANAB is already being used in the biomedical and medical device fields for precise control of pharmacological and biointegration properties.

Since 2013, Exogenesis has been part of Sematech’s program to enable extreme ultraviolet (EUV) lithography. The partners have already demonstrated ANAB technology for improving EUV pellicle transparency to 94%.

Ongoing development work for ANAB will occur in the Exogenesis facility and at the NanoTech Complex of SUNY Polytechnic Institute’s Colleges of Nanoscale Science and Engineering (SUNY Poly CNSE).