Papers by Author: K. Shimanoe

Abstract: Nickel- and Platinum-silicide nanodots with an areal density of the order of ~1011cm-2 were successfully formed on thermally-grown SiO2 through a process of ultrathin metal film formation on self-assembled Si quantum dots (QDs) on SiO2 and subsequent remote H2 plasma exposure. Chemical shifts in photoemission spectra of core lines and changes in valence band spectrum and work function value with the remote H2-plasma treatment show that silicidation of pre-grown Si-QDs is promoted by the remote H2-plasma treatment. Electrical separation among so-prepared nanodots was verified from the surface potential change after applying a dc bias between the AFM tip and the sample surface. From temporal decay in the surface potential after electron injection to the nanodots, we confirmed that silicide nanodots have superior charge retention to that of Si nanodots with almost the same size as expected in a deeper potential well for electrons in silicide dots than pure Si-QDs. In the application of silicide nanodots to a floating gate in MOS capacitors, distinct hysteresis characteristics caused by charging and discharging of several electrons per dot were verified by capacitance-voltage measurements.

Abstract: We demonstrated a new fabrication method of Pt- and Ni-silicide nanodots with an areal density of the order of ~1011 cm-2 on SiO2 through the process steps of ultrathin metal film deposition on pre-grown Si-QDs and subsequent remote H2 plasma treatments at room temperature. Verification of electrical separation among silicide nanodots was made by measuring surface potential changes due to electron injection and extraction using an AFM/Kelvin probe technique. Photoemission measurements confirm a deeper potential well of silicide nanodots than Si-QDs and a resultant superior charge retention was also verified by surface potential measurements after charging to and discharging. Also, the advantage in many electron storage per silicide nanodot was demonstrated in C-V characteristics of MIS capacitors with silicide nanodots FGs.