We fabricated nanometer-scale Ni dots and NiSi dots on an ultrathin SiO 2 layer using remote H 2 plasma and demonstrated the feasibility of remote H 2 plasma treatment for controlling the areal density of the dots. 1.8-nm-thick-Ni/SiO 2 and Ni/Siquantum dots (QDs)/SiO 2 layer were treated with remote H 2 plasma generated by the inductive coupling between an external single-turn antenna and a 60 MHz generator. When a Ni/SiO 2 was treated with remote H 2 plasma at room temperature, Ni nanodot density could be controlled in the range of 10 9 to 10 12 cm À2 by adjusting the plasma conditions. After the remote H 2 plasma treatment of the Ni/Si-QDs, the formation of electrically isolated NiSi dots with an areal density of $10 11 cm À2 was confirmed. These results imply that hydrogen radicals generated in H 2 plasma play an important role in improving surface diffusion caused by energy reduction at the Ni/SiO 2 interface. The surface potential of the Ni nanodots changes stepwise with the tip bias. This is due to the multistep electron injection into and extraction of Ni nanodots. The minimum tip biases for electron injection into Ni nanodots, NiSi dots and Si-QDs were À0:2, À0:7, and À1:0 V, respectively. This reflected the difference in electron affinity among Ni, NiSi and Si.

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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.

We formed high density platinum-silicide nanodots on an ultrathin SiO 2 layer and characterized their electronic charged states by an AFM/Kelvin probe technique. A ~1.8-nm-thick Pt film deposited on pre-grown Si quantum dots (Si-QDs) with an areal dot density of ~1.2 × 10 11 cm-2 was exposed to remote hydrogen plasma. The formation of platinum-silicide nanodots with an areal dot density of ~1.2 × 10 11 cm-2 was confirmed after examining the surface morphology and measuring the valence band spectra by AFM and XPS, respectively. The surface potential of the nanodots changed in a stepwise manner with respect to the tip bias due to multistep electron injection into and extraction from the platinum-silicide nanodots.

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