new electron-assisted
etching technique under
development at Georgia Tech
may permit routine
fabrication of nanometer-scale electronic devices
without the surface damage
caused by existing etching
systems, says Dr. H.P. Gillis,
associate professor of
chemistry at Georgia Tech."The impact on the microelectronics industry is tied to the ultimate impact of these devices, which will be quite important in the future."
Nanometer-scale devices boasting features a thousand times smaller than current circuits will fuel the next wave of development in the microelectronics industry. The technology will also be important for electro-optic devices, optical processing and radiation detectors.
Conventional ion-beam etching processes used to fabricate the tiny structures can damage their surfaces, altering optical and electronic properties and potentially limiting how the resulting devices can be used. Because of their mass and high levels of kinetic energy, the ion particles can disrupt the sensitive crystalline structure of the semiconductor surface and introduce unwanted materials.
The Georgia Tech process, however, uses low energy electrons in combination with reactive hydrogen gas to cut the required electronic features through the patterning process. Because the electrons are lighter and carry less energy, the technique does not damage the semiconductor surface.
"We deliver simultaneously a beam of low energy electrons and a beam of reactive molecules," Gillis explains. "These two species come together at the surface and the electrons stimulate the chemistry between the reactive beam and the surface. The reaction happens only at locations where both the electron beam and the reactive gas arrive."
Gillis estimates that at least two more years of work would be required to produce a practical process which could be used routinely. While he does not expect the electron-assisted technique to replace conventional etching for the current generation of semiconductor devices, he believes it represents an alternative fabrication method for future generations of nanometer-scale devices.