Home > Press > Vibrating nanorods measure thin films for microcircuits
Abstract:
A key step in many nanofabrication processes is to create thin films, sometimes only one molecule thick, by a method known as atomic layer deposition. Researchers at Cornell and Tel Aviv University have developed a new tool for nanofabricators to test the physical properties of such films.
By Bill Steele
Vibrating nanorods measure thin films for microcircuits
Ithaca, NY | Posted on December 11th, 2010
Ultrathin films are increasingly important in constructing microcircuits. Their physical characteristics often determine their electronic behavior as well as their resistance to wear.
The researchers have shown that tiny resonant cantilevers -- silicon rods anchored at one end, like a tiny diving board -- can determine the density of a film and its Young's modulus, a measure of resistance to bending. The method offers several advantages over other methods of measuring these characteristics of thin films, the researchers said, and can be used by any researchers with access to nanofabrication capabilities comparable to those at the Cornell Nanoscale Facility.
The work was reported in the Aug. 15 issue of the Journal of Applied Physics by Cornell research associate Rob Ilic, Slava Krylov, senior lecturer at Tel Aviv University and former visiting professor at Cornell, and Harold Craighead, the C.W. Lake Jr. Professor of Engineering at Cornell.
Cornell researchers have previously used tiny vibrating cantilevers just a few nanometers (billionths of a meter) thick to detect the mass of objects as small as a virus. Just as a thick guitar string vibrates at a lower note than a thinner one, adding mass to a vibrating rod changes its frequency of vibration. Coating the rod with a thin film adds detectable mass, and from the mass and thickness of the film, density can be determined.
The film also changes the cantilever's resistance to bending. To separate out this characteristic, the researchers compared in-plane (side to side) and out-of-plane (up and down) vibrations. The resistance to bending in different directions is noticeably different when the vibrating rod is wide and thin. When the cross-section of the rod is square, there is no difference between up and down and side-to-side movement.
To test their idea, the researchers fabricated a variety of cantilevers six to 10 microns (millionths of a meter) long, 45 nanometers thick and with widths varying from 45 nanometers to 1 micron. In various experiments, they applied films of aluminum, aluminum nitride and hafnium from 21.2 to 21.5 nanometers thick to the surface of the cantilevers.
A laser beam focused on the base of a cantilever supplies energy to set it vibrating, and another laser aimed at the end measures the vibration. Like a tuning fork, each rod has a resonant frequency at which it vibrates, and that depends on the dimensions and physical characteristics of the device. Comparing the resonant frequency and some of its harmonics before and after a film was applied enabled the researchers to calculate the density and Young's modulus of the film.
Over many experiments, the calculations agreed well with theoretical predictions and characteristics of films measured by other methods. Some aspects of the method of fabricating the nanocantilevers could affect the results, the researchers found, but they said accuracy could be improved.
The work was supported by the Defense Advanced Projects Research Administration, the National Science Foundation and the state of New York.
####
For more information, please click here
Contacts:
Media Contact:
Joe Schwartz
(607) 254-6235
Cornell Chronicle:
Bill Steele
(607) 255-7164
Copyright © Cornell University
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:
News and information
How do cold ions slide May 24th, 2013
Heinrich Rohrer dies at 79; a father of nanotechnology: With IBM colleague Gerd Binnig, Rohrer invented the scanning tunneling microscope, which can show individual atoms on a surface and move them around May 23rd, 2013
Gold nanocrystal vibration captured on billion-frames-per-second film May 23rd, 2013
Glowing Plant Releases Maker Kit, Enabling Anyone to Make a Glowing Plant at Home: Glowing Plant seeks funds via crowdfunding and raises almost $400,000 May 23rd, 2013
IDTechEx launches online Market Intelligence Portal May 23rd, 2013
Thin films
IDTechEx launches online Market Intelligence Portal May 23rd, 2013
Weird science: Crystals melt when they're cooled May 22nd, 2013
Moth-Inspired Nanostructures Take the Color Out of Thin Films May 17th, 2013
Govt.-Legislation/Regulation/Funding/Policy
How do cold ions slide May 24th, 2013
Gold nanocrystal vibration captured on billion-frames-per-second film May 23rd, 2013
Whirlpools on the Nanoscale Could Multiply Magnetic Memory: At the Advanced Light Source, Berkeley Lab scientists join an international team to control spin orientation in magnetic nanodisks May 22nd, 2013
Atomic-Scale Investigations Solve Key Puzzle of LED Efficiency: MIT and Brookhaven Lab scientists use electron microscopy imaging techniques to settle a solid-state controversy and raise new experimental possibilities May 22nd, 2013
Academic/Education
Inaugural Baccalaureate Class Among CNSE Graduates to Pursue Opportunities in New York: Half of undergrads from pioneering class to seek graduate degrees at CNSE; majority of master’s and doctoral degree recipients land high-tech jobs in state’s emerging nanotech industry May 16th, 2013
Anasys reports on University of Illinois study of near-field behavior of semiconductor plasmonic microparticles using AFM-IR published in APL May 14th, 2013
The University of Wyoming uses Nanoparticle Tracking Analysis to characterize nanoparticles in natural environments May 14th, 2013
Nanotechnology Pioneer Named 'Entrepreneur of the Year': Royal Society of Chemistry honors Chad Mirkin for commercializing innovations May 10th, 2013
Chip Technology
Researchers Stitch Defects into the World’s Thinnest Semiconductor May 22nd, 2013
Whirlpools on the Nanoscale Could Multiply Magnetic Memory: At the Advanced Light Source, Berkeley Lab scientists join an international team to control spin orientation in magnetic nanodisks May 22nd, 2013
Imec and GLOBALFOUNDRIES collaborate to advance high-density memory technology: STT-MRAM offers enhanced performance and scalability for embedded and standalone applications May 21st, 2013
Penn engineers' nanoantennas improve infrared sensing May 20th, 2013
Nanomedicine
UofL scientists uncover how grapefruits provide a secret weapon in medical drug delivery May 22nd, 2013
Single-Cell Transfection Tool Enables Added Control for Biological Studies: McCormick researchers develop method of delivering molecules into targeted cells May 22nd, 2013
How Gold Nanoparticles Can Help Fight Ovarian Cancer May 21st, 2013
MU Researchers Develop Radioactive Nanoparticles that Target Cancer Cells: This is an early step toward developing therapies for metastasized cancers, MU scientist says May 21st, 2013
Announcements
How do cold ions slide May 24th, 2013
Heinrich Rohrer dies at 79; a father of nanotechnology: With IBM colleague Gerd Binnig, Rohrer invented the scanning tunneling microscope, which can show individual atoms on a surface and move them around May 23rd, 2013
Gold nanocrystal vibration captured on billion-frames-per-second film May 23rd, 2013
Glowing Plant Releases Maker Kit, Enabling Anyone to Make a Glowing Plant at Home: Glowing Plant seeks funds via crowdfunding and raises almost $400,000 May 23rd, 2013
Tools
Heinrich Rohrer dies at 79; a father of nanotechnology: With IBM colleague Gerd Binnig, Rohrer invented the scanning tunneling microscope, which can show individual atoms on a surface and move them around May 23rd, 2013
Gold nanocrystal vibration captured on billion-frames-per-second film May 23rd, 2013
Researchers Stitch Defects into the World’s Thinnest Semiconductor May 22nd, 2013
Whirlpools on the Nanoscale Could Multiply Magnetic Memory: At the Advanced Light Source, Berkeley Lab scientists join an international team to control spin orientation in magnetic nanodisks May 22nd, 2013
Research partnerships
Gold nanocrystal vibration captured on billion-frames-per-second film May 23rd, 2013
Weird science: Crystals melt when they're cooled May 22nd, 2013
Researchers Stitch Defects into the World’s Thinnest Semiconductor May 22nd, 2013
Whirlpools on the Nanoscale Could Multiply Magnetic Memory: At the Advanced Light Source, Berkeley Lab scientists join an international team to control spin orientation in magnetic nanodisks May 22nd, 2013