Focused ion beams in microfabrication

Publisher Website
Google Scholar
Abstract
Microfabrication techniques are being investigated in which a focused high‐energy ion beam bombards a surface to create high‐resolution patterns of implantation doping, damage in crystal structures, or other chemical change such as molecular bond breaking. The objective is to demonstrate unique microfabrication techniques such as maskless implantation doping and the formation of self‐aligned structures. Preliminary results are presented of doped regions written in silicon by a focused boron beam. Electrical measurements on heavily doped contact regions and on a lightly doped resistive region are in good agreement with what would be expected from conventional ion implantation employing masks. The exposure of electron beam resist by a focused beam of 60‐keV helium ions is also reported. The resist sensitivity is ∼100 times greater for these ions than for electrons. The focused ion beam used in these studies was generated in a focusing arm which includes apertures, deflection plates, and an einzel lens that has been added to an existing ion implantation system. The focusing system performance is discussed and compared with the properties of a published electrostatic lens. Experimental results indicate a minimum beam spot diameter of ∼3.5 μm with a 150‐μm‐diam object aperture and a beam energy of ∼60 keV. Aperture diameters are calculated to produce a focused spot with submicrometer diameter.

This publication has 3 references indexed in Scilit: