Micromasking effect and nanostructure self-formation on the surface of lead chalcogenide epitaxial films on Si substrates during argon plasma treatment

The surface modification of lead chalcogenide epitaxial films during plasma treatment processes is investigated. With AFM and SIMS measurements it was shown that the mechanism of a microhillock formation is the micromasking effect of dislocation exit sites. Micromasking, and hence microhillock formation, takes place when fluorine sputtered from reactor chamber walls is present on the surface of the films. Micromasks are nucleated at the exits of threading dislocations when low-volatile fluoride compounds are formed due to the reaction of atomic fluorine with Al or Pb accumulated in these areas. The effects obtained are analysed from the standpoint of nanostructure formation, which requires, primarily, the suppression of the micromasking effect. A novel method of fabricating lead chalcogenide nanostructures on Si( 1 1 1) substrates via Ar plasma treatment is proposed.