Subscribe free to our newsletters via your
. Energy News .




CHIP TECH
Virtual Toothpick Helps Technologist 'Bake' the Perfect Thin-Film Confection
by Staff Writers
Greenbelt MD (SPX) Nov 18, 2013


NASA technologist Vivek Dwivedi, who has distinguished himself as the go-to-engineer for atomic layer deposition, has assembled a new reactor at NASA's Goddard Space Flight Center that he plans to use for thin-film experimentation. He is inserting one of his "virtual toothpick" technologies. Image Credit: NASA Goddard/Bill Hrybyk.

Creating thin films using a rapidly evolving technology that promises to solve some of NASA's thorniest engineering challenges is a lot like baking a cake. That's why Vivek Dwivedi, a technologist at NASA's Goddard Space Flight Center in Greenbelt, Md., has assembled a special "oven" and a "virtual toothpick" to monitor the progress of his confections.

The technology, called atomic layer deposition or ALD, is one of many techniques for applying thin films, which among other applications can improve computer memory, protect materials against corrosion, oxidation, and wear, and perform as batteries when deposited directly onto chips.

It involves placing a substrate material inside a reactor chamber, which can be likened to an oven, and sequentially pulsing different types of precursor gases to create an ultra-thin film whose layers are literally no thicker than a single atom.

Although other thin-film deposition techniques exist, ALD offers an advantage over competing approaches. It can deposit films inside pores and cavities, giving ALD the unique ability to coat in and around three-dimensional objects, which is important to NASA scientists who fly complex, three-dimensional instrument components, like baffles. Baffles are devices that help restrain fluid, gas or loose material, or prevent sound or light from spreading in a certain direction.

Given ALD's vast potential for helping to downsize instrument size and increase efficiency, Goddard technologists now are developing in-house tools to more cost effectively experiment with the technique and investigate its usefulness in a variety of space applications.

'Like Baking a Cake'
Dwivedi has built an inexpensive, relatively simple reactor chamber that measures 3 inches in diameter and 2 feet in length, as well as a suite of monitoring tools that he collectively calls his virtual toothpick. "In my mind, it's a simple process," said Dwivedi, Goddard's resident expert in ALD. "But we have to make sure everything is being done under the right conditions. It's like baking a cake."

As with baking, creating thin films using ALD requires the perfect recipe, executed under exacting conditions. In addition to choosing the gas, selected because of its properties and the job the resulting film is supposed to perform, technologists must determine how long to flow the gas inside the chamber and at what temperature and pressure level.

"What we do is place the substrate or sample inside the reactor and follow the recipe. We also cross our fingers and hope the recipe is successful. It can be a time-consuming process," Dwivedi said. When depositing iridium to coat an X-ray mirror, for example, Dwivedi said he had to wait 24 hours to see if he had succeeded.

That's why he decided to augment his reactor with the virtual toothpick, a suite of tools he uses to monitor the process in real time and test to see if his confection is done.

The Tool Set
The tool set includes a modeling program to determine how much gas to deposit on the substrate or component, a quartz crystal microbalance to actually measure the thickness of the film being deposited, and a residual gas analyzer that detects the gases that flow through the reactor, both reacted and unreacted. "These tools save time," Dwivedi said, adding he can determine in real time how well the deposition is progressing.

They also save money, he added. One gram of an iron precursor gas used to create a film can cost as much as $1,000. "We have a responsibility to use money in a cost-effective manner. So we certainly don't want to waste material in trial and error," Dwivedi said.

"What we've done is develop a less-expensive platform and tools with which to experiment," he added. "This reactor gives us an advanced processing tool, which will allow us to investigate new material systems at a fraction of the cost."

.


Related Links
Goddard Space Flight Center
Computer Chip Architecture, Technology and Manufacture
Nano Technology News From SpaceMart.com






Comment on this article via your Facebook, Yahoo, AOL, Hotmail login.

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








CHIP TECH
Next-generation semiconductors synthesis
Washington DC (SPX) Nov 14, 2013
Although silicon semiconductors are nearly universal in modern electronics, devices made from silicon have limitations-including that they cease to function properly at very high temperatures. One promising alternative are semiconductors made from combinations of aluminum, gallium, and indium with nitrogen to form aluminum nitride (AlN), gallium nitride (GaN), and indium nitride (InN), whi ... read more


CHIP TECH
Tennessee Valley Authority Makes Major Coal Plant Retirement Announcement

World set to heat up despite clean-energy efforts: IEA

Updating building energy codes: How much can your state save?

Smart water meters stop money going down the drain

CHIP TECH
Scientists invent self-healing battery electrode

Pressure Cooking to Improve Electric Car Batteries

Egypt Marches to a Saudi Drummer

Coal Drives China Emissions Growth

CHIP TECH
IKEA invests in Canadian wind project

High bat mortality from wind turbines

Wind turbines blamed in death of estimated 600,000 bats in 2012

Assessing impact of noise from offshore wind farm construction may help protect marine mammals

CHIP TECH
SunEdison Launches Solar Water Pumps In India

Vikram Solar Promotes National Solar Manufacturing Capacity

Refined materials provide booster shot for solar energy conversion

Boeing Subsidiary Spectrolab Sets New Solar Cell Efficiency World Record

CHIP TECH
Fukushima operator starts dangerous fuel-rod removal

Fukushima operator TEPCO to cut 1,000 more jobs: newspaper

Improving detection of radioactive material in nuclear waste water

Ex-Japanese Prime Minister Junichiro Koizumi urges zero nuclear power

CHIP TECH
Microbiologists reveal unexpected properties of methane-producing microbe

Boeing Amnd GOL To Boost Aviation Biofuel Production In Brazil

Neutron scattering and supercomputer demystify forces at play in biofuels

Lignin-Feasting Microbe Holds Promise for Biofuels

CHIP TECH
China shows off moon rover model before space launch

China providing space training

China launches experimental satellite Shijian-16

China Moon Rover A New Opportunity To Explore Our Nearest Neighbor

CHIP TECH
Philippines storm spurs passion for poor at climate talks

Japan lowers carbon dioxide emissions reduction target

Demonstrators at Warsaw climate summit demand emission cuts

'Missing heat' discovery prompts new estimate of global warming




The content herein, unless otherwise known to be public domain, are Copyright 1995-2014 - Space Media Network. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA Portal 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. 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