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

Corinne Miramond (1) , Dominique Vuillaume (1)

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

We have studied the electronic properties, in relation to their 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 substrate of different types (n-type and p-type) and different doping concentrations from low-doped (~1E14 cm-3) to highly doped (~1E19 cm-3) silicon substrates. 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 ~1E-7 A.cm-2 and high quality capacitance-voltage characteristics. The monolayers formed on n+-type silicon are more disordered and therefore exhibit larger leakage current densities (>1E-4 A.cm-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: Science des matériaux [cond-mat.mtrl-sci]; Matière Molle [cond-mat.soft]; Matériaux

Corinne Miramond, Dominique Vuillaume. 1-octadecene monolayers on Si(111) hydrogen-terminated surfaces: effects of substrate doping.. 2004. ⟨hal-00001568⟩