Nanotechnology Now

Our NanoNews Digest Sponsors

Heifer International

Wikipedia Affiliate Button

Home > Press > New technique makes it easier to etch semiconductors

Graphic by Xiuling Li

Metal-assisted chemical etching uses two steps. First, a thin layer of gold is patterned on top of a semiconductor wafer with soft lithography (left). The gold catalyzes a chemical reaction that etches the semiconductor form the top down, creating three-dimensional structures for optoelectronic applications (right).
Graphic by Xiuling Li

Metal-assisted chemical etching uses two steps. First, a thin layer of gold is patterned on top of a semiconductor wafer with soft lithography (left). The gold catalyzes a chemical reaction that etches the semiconductor form the top down, creating three-dimensional structures for optoelectronic applications (right).

Abstract:
Creating semiconductor structures for high-end optoelectronic devices just got easier, thanks to University of Illinois researchers.

New technique makes it easier to etch semiconductors

Posted on December 22nd, 2011

The team developed a method to chemically etch patterned arrays in the semiconductor gallium arsenide, used in solar cells, lasers, light emitting diodes (LEDs), field effect transistors (FETs), capacitors and sensors. Led by electrical and computer engineering professor Xiuling Li, the researchers describe their technique in the journal Nano Letters.

A semiconductor's physical properties can vary depending on its structure, so semiconductor wafers are etched into structures that tune their electrical and optical properties and connectivity before they are assembled into chips.

Semiconductors are commonly etched with two techniques: "Wet" etching uses a chemical solution to erode the semiconductor in all directions, while "dry" etching uses a directed beam of ions to bombard the surface, carving out a directed pattern. Such patterns are required for high-aspect-ratio nanostructures, or tiny shapes that have a large ratio of height to width. High-aspect-ratio structures are essential to many high-end optoelectronic device applications.

While silicon is the most ubiquitous material in semiconductor devices, materials in the III-V (pronounced three-five) group are more efficient in optoelectronic applications, such as solar cells or lasers.

Unfortunately, these materials can be difficult to dry etch, as the high-energy ion blasts damage the semiconductor's surface. III-V semiconductors are especially susceptible to damage.

To address this problem, Li and her group turned to metal-assisted chemical etching (MacEtch), a wet-etching approach they had previously developed for silicon. Unlike other wet methods, MacEtch works in one direction, from the top down. It is faster and less expensive than many dry etch techniques, according to Li. Her group revisited the MacEtch technique, optimizing the chemical solution and reaction conditions for the III-V semiconductor gallium arsenide (GaAs).

The process has two steps. First, a thin film of metal is patterned on the GaAs surface. Then, the semiconductor with the metal pattern is immersed in the MacEtch chemical solution. The metal catalyzes the reaction so that only the areas touching metal are etched away, and high-aspect-ratio structures are formed as the metal sinks into the wafer. When the etching is done, the metal can be cleaned from the surface without damaging it.

"It is a big deal to be able to etch GaAs this way," Li said. "The realization of high-aspect-ratio III-V nanostructure arrays by wet etching can potentially transform the fabrication of semiconductor lasers where surface grating is currently fabricated by dry etching, which is expensive and causes surface damage."

To create metal film patterns on the GaAs surface, Li's team used a patterning technique pioneered by John Rogers, the Lee J. Flory-Founder Chair and a professor of materials science and engineering at the U. of I. Their research teams joined forces to optimize the method, called soft lithography, for chemical compatibility while protecting the GaAs surface. Soft lithography is applied to the whole semiconductor wafer, as opposed to small segments, creating patterns over large areas - without expensive optical equipment.

"The combination of soft lithography and MacEtch make the perfect combination to produce large-area, high-aspect-ratio III-V nanostructures in a low-cost fashion," said Li, who is affiliated with the Micro and Nanotechnology Laboratory, the Frederick Seitz Materials Research Laboratory and the Beckman Institute for Advanced Science and Technology at the U. of I.

Next, the researchers hope to further optimize conditions for GaAs etching and establish parameters for MacEtch of other III-V semiconductors. Then, they hope to demonstrate device fabrication, including distributed Bragg reflector lasers and photonic crystals.

"MacEtch is a universal method as long as the right condition for deferential etching with and without metal can be found," Li said.

The Department of Energy and the National Science Foundation supported this work.

####

For more information, please click here

Contacts:
Liz Ahlberg
Physical Sciences Editor
217-244-1073


Xiuling Li
217-265-6354

Copyright © University of Illinois at Urbana-Champaign

If you have a comment, please Contact us.

Issuers of news releases, not 7th Wave, Inc. or Nanotechnology Now, are solely responsible for the accuracy of the content.

Bookmark:
Delicious Digg Newsvine Google Yahoo Reddit Magnoliacom Furl Facebook

Related Links

The paper, “Formation of High Aspect Ratio GaAs Nanostructures With Metal-Assisted Chemical Etching,” is available online:

Related News Press

News and information

Heating quantum matter: A novel view on topology: Physicists demonstrate how heating up a quantum system can be used as a universal probe for exotic states of matter August 22nd, 2017

A Tougher Tooth: A new dental restoration composite developed by UCSB scientists proves more durable than the conventional material August 22nd, 2017

Nagoya physicists resolve long-standing mystery of structure-less transition: Nagoya University-led team of physicists use a synchrotron radiation X-ray source to probe a so-called 'structure-less' transition and develop a new understanding of molecular conductors August 21st, 2017

Tokai University research: Nanomaterial wrap for improved tissue imaging August 21st, 2017

Display technology/LEDs/SS Lighting/OLEDs

The power of perovskite: OIST researchers improve perovskite-based technology in the entire energy cycle, from solar cells harnessing power to LED diodes to light the screens of future electronic devices and other lighting applications August 18th, 2017

Nanocrystalline LEDs: Red, green, yellow, blue ... August 7th, 2017

Nanoparticles could spur better LEDs, invisibility cloaks July 19th, 2017

Cambridge Nanotherm partners with Inabata for global sales and distribution June 20th, 2017

Govt.-Legislation/Regulation/Funding/Policy

Nagoya physicists resolve long-standing mystery of structure-less transition: Nagoya University-led team of physicists use a synchrotron radiation X-ray source to probe a so-called 'structure-less' transition and develop a new understanding of molecular conductors August 21st, 2017

Researchers printed graphene-like materials with inkjet August 17th, 2017

Freeze-dried foam soaks up carbon dioxide: Rice University scientists lead effort to make novel 3-D material August 16th, 2017

2-faced 2-D material is a first at Rice: Rice University materials scientists create flat sandwich of sulfur, molybdenum and selenium August 14th, 2017

Chip Technology

Nagoya physicists resolve long-standing mystery of structure-less transition: Nagoya University-led team of physicists use a synchrotron radiation X-ray source to probe a so-called 'structure-less' transition and develop a new understanding of molecular conductors August 21st, 2017

Silk could improve sensitivity, flexibility of wearable body sensors August 20th, 2017

Freeze-dried foam soaks up carbon dioxide: Rice University scientists lead effort to make novel 3-D material August 16th, 2017

Two Scientists Receive Grants to Develop New Materials: Chad Mirkin and Monica Olvera de la Cruz recognized by Sherman Fairchild Foundation August 16th, 2017

Sensors

Silk could improve sensitivity, flexibility of wearable body sensors August 20th, 2017

Researchers printed graphene-like materials with inkjet August 17th, 2017

Sensing technology takes a quantum leap with RIT photonics research: Office of Naval Research funds levitated optomechanics project August 10th, 2017

Giant enhancement of electromagnetic waves revealed within small dielectric particles: Scientists have done for the first time direct measurements of giant electromagnetic fields July 8th, 2017

Nanoelectronics

GLOBALFOUNDRIES Demonstrates 2.5D High-Bandwidth Memory Solution for Data Center, Networking, and Cloud Applications: Solution leverages 2.5D packaging with low-latency, high-bandwidth memory PHY built on FX-14™ ASIC design system August 9th, 2017

GLOBALFOUNDRIES, Silicon Mobility Deliver the Industry’s First Automotive FPCU to Boost Performance for Hybrid and Electric Vehicles: Silicon Mobility and GF’s 55nm LPx -enabled platform, with SST’s highly-reliable SuperFlash® memory technology, boosts automotive performance, ene August 3rd, 2017

Scientists discover new magnet with nearly massless charge carriers July 29th, 2017

Atomic discovery opens door to greener, faster, smaller electronic circuitry: Scientists find way to correct communication pathways in silicon chips, making them perfect July 27th, 2017

Discoveries

Heating quantum matter: A novel view on topology: Physicists demonstrate how heating up a quantum system can be used as a universal probe for exotic states of matter August 22nd, 2017

A Tougher Tooth: A new dental restoration composite developed by UCSB scientists proves more durable than the conventional material August 22nd, 2017

Nagoya physicists resolve long-standing mystery of structure-less transition: Nagoya University-led team of physicists use a synchrotron radiation X-ray source to probe a so-called 'structure-less' transition and develop a new understanding of molecular conductors August 21st, 2017

Tokai University research: Nanomaterial wrap for improved tissue imaging August 21st, 2017

Announcements

Heating quantum matter: A novel view on topology: Physicists demonstrate how heating up a quantum system can be used as a universal probe for exotic states of matter August 22nd, 2017

A Tougher Tooth: A new dental restoration composite developed by UCSB scientists proves more durable than the conventional material August 22nd, 2017

Nagoya physicists resolve long-standing mystery of structure-less transition: Nagoya University-led team of physicists use a synchrotron radiation X-ray source to probe a so-called 'structure-less' transition and develop a new understanding of molecular conductors August 21st, 2017

Tokai University research: Nanomaterial wrap for improved tissue imaging August 21st, 2017

Energy

The power of perovskite: OIST researchers improve perovskite-based technology in the entire energy cycle, from solar cells harnessing power to LED diodes to light the screens of future electronic devices and other lighting applications August 18th, 2017

Freeze-dried foam soaks up carbon dioxide: Rice University scientists lead effort to make novel 3-D material August 16th, 2017

Two Scientists Receive Grants to Develop New Materials: Chad Mirkin and Monica Olvera de la Cruz recognized by Sherman Fairchild Foundation August 16th, 2017

Fewer defects from a 2-D approach August 15th, 2017

Battery Technology/Capacitors/Generators/Piezoelectrics/Thermoelectrics/Energy storage

Candy cane supercapacitor could enable fast charging of mobile phones August 17th, 2017

Rice U. scientists map ways forward for lithium-ion batteries for extreme environments: Paper details developments toward high-temperature batteries July 27th, 2017

Regulation of two-dimensional nanomaterials: New driving force for lithium-ion batteries July 26th, 2017

Ultrathin device harvests electricity from human motion July 23rd, 2017

Solar/Photovoltaic

The power of perovskite: OIST researchers improve perovskite-based technology in the entire energy cycle, from solar cells harnessing power to LED diodes to light the screens of future electronic devices and other lighting applications August 18th, 2017

Fewer defects from a 2-D approach August 15th, 2017

Controlled manipulation: Scientists at FAU are investigating the properties of hybrid systems consisting of carbon nanostructures and a dye August 8th, 2017

Simultaneous Design and Nanomanufacturing Speeds Up Fabrication: Method enhances broadband light absorption in solar cells August 5th, 2017

Printing/Lithography/Inkjet/Inks/Bio-printing

Researchers printed graphene-like materials with inkjet August 17th, 2017

Simultaneous Design and Nanomanufacturing Speeds Up Fabrication: Method enhances broadband light absorption in solar cells August 5th, 2017

Meniscus-assisted technique produces high efficiency perovskite PV films July 7th, 2017

Carbodeon demonstrates NanoDiamond nickel coatings with enhanced tribological properties June 7th, 2017

NanoNews-Digest
The latest news from around the world, FREE



  Premium Products
NanoNews-Custom
Only the news you want to read!
 Learn More
NanoTech-Transfer
University Technology Transfer & Patents
 Learn More
NanoStrategies
Full-service, expert consulting
 Learn More











ASP
Nanotechnology Now Featured Books




NNN

The Hunger Project