Effects of electron irradiation on alkaline earth fluorides

Abstract

Alkaline earth fluorides are important materials in the electronics industry because of their use in the epitaxial growth of semiconductor-on-insulator (SOI) devices. Their main advantages are their close lattice match with the common semiconductors, and the fact that they evaporate as molecular units upon heating which implies good control of film stoichiometry in Molecular Beam Epitaxy. More recently, further interest has developed relating to their use in nanolithography because they are materials which can be suitably patterned with an electron beam in device processing.Moreover, some inorganic fluorides potentially offer inherently higher resolution than resists so far used.Various studies have been made on the effects of irradiation on these Group IIA fluorides. It has also been noted during electron microscope characterization of the SOI structures that these fluorides are very easily damaged. Since image detail is lost, it has been suggested that the fluorides are becoming amorphous.