Molecular-beam epitaxy has been used to grow films that are almost entirely IrSi3 by codeposition of Si and Ir in a 3:1 ratio on Si(111) substrates. Bragg-Brentano and Seemann-Bohlin x-ray diffraction reveal that polycrystalline IrSi3 films form as low as 490°C, the lowest temperature yet reported for growth of this iridium silicide phase. Above 580°C this hexagonal phase becomes textured, with as many as seven preferred growth orientations on Si(111). Samples codeposited on Si(111) between 680 and 780°C consist almost entirely of IrSi3 with its c axis perpendicular to the substrate's surface. At higher substrate temperatures, near 830°C growth of IrSi3 with its c axis in the plane of the substrate dominates. Atomic force microscopy shows that there is a difference in the surface morphology of the c-axis in-plane and perpendicular growth modes. Transmission electron microscope diffraction and in situ low-energy electron diffraction verify that both of these IrSi3 growth modes are epitaxially registered with their substrates. To check the quality of this epitaxy ion-beam channeling and x-ray rocking curves were used. The data from the epitaxial samples have channeling χmin ratios as low as 0.64. The x-ray rocking curves for these IrSi3 films are narrow, with full-width-at- half-maxima of as little as 0.07°.
ASJC Scopus subject areas
- Physics and Astronomy(all)