Image force interactions at the interface between an insulator and a semiconductor

A simplified classical analysis is made of the image force interactions of ions in an insulator near an interface with a semiconductor. The ions induce a countercharge of electrons in the semiconductor, and these screen the field due to the ions. With respect to the image force, the semiconductor may behave like either a metal or a dielectric, depending on the magnitude of Debye screening length relative to the distance of the ions from the interface. An approximate solution of the problem for intermediate cases gives a lateral interaction potential that describes an effective lateral attraction among the components of the system. A numerical example is given for the SiO2–Si interface, and possible applications to other systems are discussed.