1-octadecene monolayers on Si(111) hydrogen-terminated surfaces : effect of substrate doping

Corinne Miramond , Dominique Vuillaume (1)

1 IEMN - Institut d’Électronique, de Microélectronique et de Nanotechnologie - UMR 8520

We have studied the electronic properties, in relation to structural properties, of monolayers of 1-octadecene attached on a hydrogen-terminated (111) silicon surface. The molecules are attached using the free-radical reaction between CC and SiH activated by an ultraviolet illumination. We have compared the structural and electrical properties of monolayers formed on silicon substrates of different types (⁠n type and p type) and different doping concentrations, from low-doped (∼1014cm−3) to highly doped (∼1019cm−3)⁠. We show that the monolayers on n-, p-, and p+-silicon are densely packed and that they act as very good insulating films at a nanometer thickness with leakage currents as low as ∼10−7Acm−2 and high-quality capacitance-voltage characteristics. The monolayers formed on n+-type silicon are more disordered and therefore exhibit larger leakage current densities (>10−4Acm−2) when embedded in a silicon∕monolayer∕metal junction. The inferior structural and electronic properties obtained with n+-type silicon pinpoint the important role of surface potential and of the position of the surface Fermi level during the chemisorption of the organic monolayers.

Domaines: Sciences de l'ingénieur [physics]

Corinne Miramond, Dominique Vuillaume. 1-octadecene monolayers on Si(111) hydrogen-terminated surfaces : effect of substrate doping. Journal of Applied Physics, 2004, 96 (3), pp.1529-1536. ⟨10.1063/1.1767984⟩. ⟨hal-00140729⟩