Effect of the weak form of adsorption on the Si surface charge

The kinetics of charging of a real Si surface under low temperature heating is investigated. The charging of the surface is attributed to the weak adsorption of water. The dipole–charge interaction mechanism is put forward to explain the behaviour of water molecules on the surface. Being a dipole, the molecule is attaching to the surface with the pole of the opposite sign with respect to the sign of the substrate majority carriers. This explains the established dependence of the localised surface charge sign on the conductivity type of the silicon substrate. The binding energy, which is characteristic for the adsorption dynamics is estimated. The functional dependence of the characteristic kinetics time on the binding energy is established. q1998 Elsevier Science B.V. All rights reserved.