DIAMOND CRYSTAL-GROWTH ON SILICON AND ITS INTERFACIAL CHARACTERIZATION

Diamond crystals have been grown on an amorphous buffer layer formed on silicon substrates using electron-assisted chemical vapor deposition using tantalum filaments and gas fed by the natural circulation of thermal convection. In a closed large-volume reactor, diamond films with good crystallinity were obtained on (111)Si substrates; the narrowest full width at half-maximum at the Raman shift of 1332.4 cm-1 was 4.9 cm-1. Lattice images of diamond as well as silicon were simultaneously obtained at the interface of the diamond film using high-resolution transmission electron microscopy (HRTEM). The observed buffer layer 2 nm thick was confirmed in the amorphous layer by nanometer-scale-area electron diffraction with a 2 nm beam probe. Diamond films were preferentially oriented to the [1BAR11BAR] direction. HRTEM images of the interface were in good agreement with a geometric atomic projection scheme to the (110) plane of the diamond structure; an sp3 axis of the tetrahedral structure was formed perpendicular to an amorphous buffer layer on the silicon substrate.