Philip D. Rack

 UT office (865) 974-5344
ORNL office (865) 241-1598
fax (865) 974-4115

Nanoscale Focused Electron Beam Stimulated Processing

The ability to manipulate materials at the nanoscale is critical for the nanotechnology revolution that is occurring.  While standard and emerging lithographic techniques will continue to play a critical role in nanomanufacturing, future nanoscale procesing will also likely require site-selective directed assembly techniques for critical level processing.  This is more than just economics, more than just the provision of jobs and new opportunities. It has the potential to change the landscape of nanotechnology. Furthermore, as geometries shrink and wafer cost-of-ownership increases, nanoscale re-manufacturing or repair techniques will be increasingly more important.  Other immediate applications for nanoscale directed assembly or direct write techniques include: nanoscale device prototyping, nanoscale lithographic mask and chip repair, and site-selective metrology sample preparation for failure analysis of nanoscale devices. 

 

To this end, we are investigating focused electron beam stimulated processing including electron beam induced deposition (EBID) and electron beam induced etching (EBIE).  Having successfully developed a first generation gas delivery system and explored the efficacy of nanoscale electron beam stimulated directed assembly and etching we are currently exploring three aspects of this process, namely:

  1. Fundamental studies of the electron-gas, electron-solid, and gas-solid interactions

  2. Engineering optimization of the precursor gas delivery and the electron beam scanning parameters

  3. Development of in-situ process-monitoring schemes and demonstrate nanoscale device prototyping and repair applications. 

  4. The development of a program that simulates the EBID and EBIE process.

The following summarizes some of my groups previous accomplishments for the electron stimulated processing program. 

To perform the electron beam processing, a gas delivery system was designed and attached to a Hitachi S-3500N and S-4300 Variable Pressure Scanning Electron Microscope (VPSEM).  The VPSEM has a tungsten hairpin source and is equipped with a backscatter detector, an energy dispersive x–ray spectrometer (EDS), and has a pump system designed to operate in high vacuum (<0.1Pa) or variable pressure mode (0.1 – 300 Pa).  The gas delivery system is designed to deliver up to four gases through a hypodermic needle for localized gas injection.  The injection system is mounted on a wobble stick for 3–dimensional positioning capability.  Figure 6 shows a) the gas injection flange, b) the gas delivery needle, and c) an SEM micrograph of the delivery needle in close proximity (~1mm) to the substrate for localized gas delivery.

 EBID

The following figure summarizes some of the research that my group has done in electron beam induced deposition. 

 

References

  1. Steven J. Randolph, Jason D. Fowlkes, Philip D. Rack, Focused, Nanoscale Electron-Beam-Induced Deposition and Etching, Critical Reviews of Solid State and Materials Sciences, Vol. 31, p. 55-89 (October 2006)

  2. Steven J. Randolph, Jason D. Fowlkes, Philip D. Rack, Single- and bi-layer nanolithography approaches utilizing electron-beam-induced deposition, Journal of Vacuum Science and Technology B, Microelectronics and Nanometer Structures (submittted 5/06)

  3. Young R. Choi, Philip D. Rack, Steven J. Randolph, Daryl A. Smith, and David C. Joy, Pressure effect of growing with electron beam induced deposition with WF6 and TEOS precursor, Vol. 28 no. 6, pp. 3111-318, (December 2006) *image selected for journal cover. 

  4. J.D. Fowlkes, S.J. Randolph, P.D. Rack, Growth and Simulation of High – Aspect Ratio Nanopillars by Primary and Secondary Electron – Induced Deposition Journal of Vacuum Science and Technology B, Microelectronics and Nanometer Structures, Vol 23, no 6, pp 2825-2832 (November/December 2005). 

  5. S.J. Randolph, J.D. Fowlkes, P.D. Rack Focused electron beam-induced etching of silicon dioxide, Journal of Applied Physics Vol. 98 034902 pp. 1-6 (August 2005).

  6. S.J. Randolph, J.D. Fowlkes, P.D. Rack Effects of heat generation during electron beam induced deposition of nanostructures, Journal of Applied Physics, Vol. 97 124312 pp. 1-8 (June 2005). 

  7. X. Yang, S.J. Randolph, P.D. Rack, L.R. Baylor, H. Cui, W.L. Gardner, and M.L. Simpson, Integrated tungsten nanofiber field emission cathodes selectively grown by nanoscale electron beam-induced deposition, Applied Physics Letters Vol 86 No. 18 pp. 183106 1-3 (May 2005).

  8. Philip D. Rack, Steven Randolph, Yuepeng Deng, Jason Fowlkes, Young Choi and David C. Joy, Nanonscale Electron Beam Stimulated Processing, vol. 82, no.14, pp. 2326-2328 (April 2003).  (*also selected for publication in the April 14, 2003 issue of the Virtual Journal of Nanoscale Science & Technology).