DRY ETCHING FOR NANOMETER-SCALE FABRICATION.

Conventional integrated circuit fabrication is currently making the transition from wet to dry etching in the effort to shrink feature sizes to about 1 micron. These plasma etching techniques, though, are not limited to micron dimensions; devices and structures smaller than 100 nm can be made. Using e-beam lithography and reactive ion etching, patterns down to about 20 nm have been made in tri-level stencils and in semiconductor substrates. Working silicon MOSFETs with gate widths down to about 30 nm have also been made. These MOSFET devices are so small that individual electron trapping events can be observed. These devices are being studied to give a better understanding of the physics of electronic conduction in small devices and better define the limits of microfabrication.