Oxide nanodots and ultrathin layers fabricated on silicon using nonfocused multicharged ion beams

We have used slow multicharged argon ions in ultrahigh vacuum with a partial pressure of oxygen to form ultrathin (subnanometer) oxide dots of a few tens of nanometer diameter on a silicon surface. The main characteristic of this technique is that the incident multicharged ion does not penetrate below the surface, so there is no implantation-induced modifications of the substrate. Thus, we utilized a unique possibility provided by the multicharged ions interaction with surfaces of solids, the noncontact trampoline effect, to open the bonds of hydrogenated silicon, and replace it with oxygen. This article presents the fundamentals of slow multicharged ion interaction with a surface, the experimental multicharged ion beam line build at X-ion laboratory, and obtained results of oxide dot formation on silicon, using them as a mask in a reactive ion etching process to grow three-dimensional crystalline silicon structures. Potential applications are in nanoflash-multidot type nonvolatile memories. (C) 2000 American Vacuum Society. [S0734-211X(00)17706-6].