Subscribe free to our newsletters via your
. 24/7 Space News .




Subscribe free to our newsletters via your




















CHIP TECH
Thinking thin brings new layering and thermal abilities to the semiconductor industry
by Staff Writers
Washington DC (SPX) Jul 24, 2017


The same 20-micron spalled GaN film, demonstrating the film's flexibility. Credit Bedell/IBM Research

What would a simple technique to remove thin layers from otherwise thick, rigid semiconductor crystals mean for the semiconductor industry? This concept has been actively explored for years, as integrated circuits made on thin layers hold promise for developments including improved thermal characteristics, lightweight stackability and a high degree of flexibility compared to conventionally thick substrates.

In a significant advance, a research group from IBM successfully applied their new "controlled spalling" layer transfer technique to gallium nitride (GaN) crystals, a prevalent semiconductor material, and created a pathway for producing many layers from a single substrate.

As they report in the Journal of Applied Physics, from AIP Publishing, controlled spalling can be used to produce thin layers from thick GaN crystals without causing crystalline damage. The technique also makes it possible to measure basic physical properties of the material system, like strain-induced optical effects and fracture toughness, which are otherwise difficult to measure.

Single-crystal GaN wafers are extremely expensive, where just one 2-inch wafer can cost thousands of dollars, so having more layers means getting more value out of each wafer. Thinner layers also provide performance advantages for power electronics, since it offers lower electrical resistance and heat is easier to remove.

"Our approach to thin film removal is intriguing because it's based on fracture," said Stephen W. Bedell, research staff member at IBM Research and one of the paper's authors. "First, we first deposit a nickel layer onto the surface of the material we want to remove. This nickel layer is under tensile strength - think drumhead. Then we simply roll a layer of tape onto the nickel, hold the substrate down so it can't move, and then peel the tape off. When we do this, the stressed nickel layer creates a crack in the underlying material that goes down into the substrate and then travels parallel to the surface."

Their method boils down to simply peeling off the tape, nickel layer and a thin layer of the substrate material stuck to the nickel.

"A good analogy of how remarkable this process is can be made with a pane of glass," Bedell said. "We're breaking the glass in the long direction, so instead of a bunch of broken glass shards, we're left with two full sheets of glass. We can control how much of the surface is removed by adjusting the thickness of the nickel layer. Because the entire process is done at room temperature, we can even do this on finished circuits and devices, rendering them flexible."

The group's work is noteworthy for multiple reasons. For starters, it's by far the simplest method of transferring thin layers from thick substrates. And it may well be the only layer transfer method that's materially agnostic.

"We've already demonstrated the transfer of silicon, germanium, gallium arsenide, gallium nitride/sapphire, and even amorphous materials like glass, and it can be applied at nearly any time in the fabrication flow, from starting materials to partially or fully finished circuits," Bedell said.

Turning a parlor trick into a reliable process, working to ensure that this approach would be a consistent technique for crack-free transfer, led to surprises along the way.

"The basic mechanism of substrate spalling fracture started out as a materials science problem," he said. "It was known that metallic film deposition would often lead to cracking of the underlying substrate, which is considered a bad thing. But we found that this was a metastable phenomenon, meaning that we could deposit a thick enough layer to crack the substrate, but thin enough so that it didn't crack on its own - it just needed a crack to get started."

Their next discovery was how to make the crack initiation consistent and reliable. While there are many ways to generate a crack - laser, chemical etching, thermal, mechanical, etc. - it turns out that the simplest way, according to Bedell, is to terminate the thickness of the nickel layer very abruptly near the edge of the substrate.

"This creates a large stress discontinuity at the edge of the nickel film so that once the tape is applied, a small pull on the tape consistently initiates the crack in that region," he said.

Though it may not be obvious, gallium nitride is a vital material to our everyday lives. It's the underlying material used to fabricate blue, and now white, LEDs (for which the 2014 Nobel Prize in physics was awarded) as well as for high-power, high-voltage electronics. It may also prove useful for inherent biocompatibility, which when combined with control spalling may permit ultrathin bioelectronics or implantable sensors.

"Controlled spalling has already been used to create extremely lightweight, high-efficiency GaAs-based solar cells for aerospace applications and flexible state-of-the-art circuits," Bedell said.

The group is now working with research partners to fabricate high-voltage GaN devices using this approach. "We've also had great interaction with many of the GaN technology leaders through the Department of Energy's ARPA-E SWITCHES program and hope to use controlled spalling to enable novel devices through future partnerships," Bedell said.

The article, "Layer transfer of bulk gallium nitride by controlled spalling," is authored by Stephen W. Bedell, Paul Lauro, John A. Ott, Keith E. Fogel and Devendra K. Sadana. The article appeared in The Journal of Applied Physics July 11, 2017 (DOI: 10.1063/1.4986646

CHIP TECH
Breakthrough in spintronics
Wurzburg, Germany (SPX) Jul 21, 2017
The material class of topological insulators is presently the focus of international solids research. These materials are electrically insulating within, because the electrons maintain strong bonds to the atoms. At their surfaces, however, they are conductive due to quantum effects. What is more: The electron has a built-in compass needle, the spin, whose orientation is capable of transmit ... read more

Related Links
American Institute of Physics
Computer Chip Architecture, Technology and Manufacture
Nano Technology News From SpaceMart.com

Thanks for being here;
We need your help. The SpaceDaily news network continues to grow but revenues have never been harder to maintain.

With the rise of Ad Blockers, and Facebook - our traditional revenue sources via quality network advertising continues to decline. And unlike so many other news sites, we don't have a paywall - with those annoying usernames and passwords.

Our news coverage takes time and effort to publish 365 days a year.

If you find our news sites informative and useful then please consider becoming a regular supporter or for now make a one off contribution.

SpaceDaily Contributor
$5 Billed Once


credit card or paypal
SpaceDaily Monthly Supporter
$5 Billed Monthly


paypal only

Comment using your Disqus, Facebook, Google or Twitter login.

Share this article via these popular social media networks
del.icio.usdel.icio.us DiggDigg RedditReddit GoogleGoogle

CHIP TECH
Astronauts gear up for space with tough Russian training

ESA astronaut Paolo Nespoli starts third mission on Space Station

Voyager spacecraft still in communication 40 years out into the void

NextSTEP Partners Develop Ground Prototypes to Expand our Knowledge of Deep Space Habitats

CHIP TECH
Three Up, Three Down as NASA Tests RS-25 Flight Controller

Iran in 'successful' test of satellite-launch rocket

Aerojet Rocketdyne's RS-25 Flight Controller Goes Three for Three in SLS Test

India looks to more launches with new facility from 2018

CHIP TECH
Eclipse Balloons to Study Effect of Mars-Like Environment on Life

Portals to new worlds: Martian exploration near the North Pole

Opportunity enters Automode during solar conjunction pause

For Moratorium on Sending Commands to Mars, Blame the Sun

CHIP TECH
China develops sea launches to boost space commerce

Chinese satellite Zhongxing-9A enters preset orbit

Chinese Space Program: From Setback, to Manned Flights, to the Moon

Chinese Rocket Fizzles Out, Puts Other Launches on Hold

CHIP TECH
Iridium Announces Third Iridium NEXT Launch Date

ASTROSCALE Raises a Total of $25 Million in Series C Led by Private Companies

LISA Pathfinder: bake, rattle and roll

A Final Farewell to LISA Pathfinder

CHIP TECH
Fundamental breakthrough in the future of designing materials

Multitasking monolayers

A new material emits white light when exposed to electricity

Writing with the electron beam: Now in silver

CHIP TECH
Breakthrough Starshot launches tiny spacecraft in quest for Alpha Centauri

Has Cassini found a universal driver for prebiotic chemistry at Titan?

An Earth-like atmosphere may not survive Proxima b's orbit

A New Search for Extrasolar Planets from the Arecibo Observatory

CHIP TECH
New Horizons Video Soars over Pluto's Majestic Mountains and Icy Plains

Juno spots Jupiter's Great Red Spot

New evidence in support of the Planet Nine hypothesis

NASA's New Horizons Team Strikes Gold in Argentina




Memory Foam Mattress Review
Newsletters :: SpaceDaily :: SpaceWar :: TerraDaily :: Energy Daily
XML Feeds :: Space News :: Earth News :: War News :: Solar Energy News






The content herein, unless otherwise known to be public domain, are Copyright 1995-2017 - Space Media Network. All websites are published in Australia and are solely subject to Australian law and governed by Fair Use principals for news reporting and research purposes. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA news reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. All articles labeled "by Staff Writers" include reports supplied to Space Media Network by industry news wires, PR agencies, corporate press officers and the like. Such articles are individually curated and edited by Space Media Network staff on the basis of the report's information value to our industry and professional readership. Advertising does not imply endorsement, agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. Privacy Statement