High Density Formation of Iron Nanodots on SiO2 Induced by Remote Hydrogen Plasma

We have successfully formed Fe-nanodots with an areal dot density as high as ~2.4×1011 cm-2 on thermally grown SiO2 by exposing a 3-nm-thick Fe layer to a remote plasma of pure H2 without external heating. During remote H2 plasma exposure, the surface temperature rising up to ~500 °C was caused by surface recombination of atomic H, which enhanced surface migration of Fe atoms and promoted self-assembling nanodots. Electrical separation among Fe-nanodots was also verified from the changes in surface potential after charge injection using an AFM/Kelvin probe technique. The magnetic characterization by using magnetic force microscopy suggests that Fe-nanodots act as not only charge storage nodes but also spin-dependent active elements.