| Summary: | 博士 === 國立中興大學 === 材料科學與工程學系所 === 99 === The aim of this study is to prepare the TiVCr and TiVCrZrY multi-element coatings onto Si substrates in Ar and/or N2 atmosphere by magnetron sputtering using a single equimolar TiVCr and TiVCrZrY alloy target, respectively. The deposition parameters were varied to investigate the change of structural and properties of these coatings. The research is mainly divided into six sections. In the first section, the TiVCr coatings were deposited onto Si substrates to see the influence of working pressure (0.33-1 Pa) on structure and properties of these coatings. In this study, the TiVCr coatings have a composite structure with amorphous and body-centered cubic (bcc) crystal phases comprised of bundles of fine fibrous structures and V- shaped columnar structures, respectively. Compared with the amorphous zone, the crystalline zone has a denser and more compact structure. The coating microstructure became more porous as working pressure increased. Consequently, the crystal zones of the deposited coatings at 0.33 Pa obtained higher hardness (11.6 GPa) while the deposited coatings at 1 Pa achieved lower hardness (4.5 GPa). In the second section, influence of the substrate bias (0-15 W) on the structure and properties of these coatings were investigated. The deposited TiVCr and TiVCrZrY alloy films possessed a bcc and an hcp solid-solution structure, respectively. As the bias power increased, the microstructure of the films obviously changed from a porous to a dense columnar feature, and the density of the voids existing between the columns decreased. Accordingly, the physical properties of the films were improved. The hardness of the TiVCr and TiVCrZrY films was enhanced to about 11 and 14 GPa, and the electrical resistivity was lowered to 80 and 100 μΩ-cm, respectively. In the third section, (TiVCr)N coatings were deposited under various N2-to-total (N2 + Ar) flow ratio, RN, at room temperature without applying substrate bias. As the RN increases, the microstructure of the coatings obviously changed from a porous to a compact and dense columnar structure. Therefore, the hardness of the (TiVCr)N was enhanced to about 15 GPa, and the electrical resistivity was lowered to 10,000 μΩ-cm. In the fourth section, we reports the influence of growth conditions on the characteristics of (TiVCrZrY)N coatings prepared by reactive magnetron sputtering at various RN. The voids in the coatings are eliminated and the growth of the columnar crystal structures is inhibited along with an increasing RN. As a consequence, highly packed equiaxed amorphous structures with smooth surfaces are formed. The coatings accordingly achieved a pronounce hardness of 17.5 GPa when RN = 100%. In the fifth section, the (TiVCr)N coatings were deposited on Si substrate via rf magnetron sputtering of a TiVCr alloy target under dc bias in a N2/Ar atmosphere. The preferred orientation of the (TiVCr)N coatings changed from (1 1 1) to (2 0 0) with increasing RN. In addition, the microstructure of the nitride coatings was also converted from a columnar structure with void boundaries and rough-faceted surface to a very dense structure with a smooth-domed surface. The grain size of the (TiVCr)N coatings decreased as the RN was increased. Accordingly, the hardness of the (TiVCr)N coatings was enhanced from 4.06 to18.74 GPa as the RN was increased. In the final section, 15 nm-thick sputter-deposited TiVCr alloy thin films were developed as diffusion barrier layers for Cu interconnects. In conjunction with X-ray diffraction, transmission electron microscopy, and energy-dispersive spectroscopy analyses, the Si/TiVCr/Cu film stack remained stable at a high temperature of 700 °C for 30 min. The mixed TiVCr refractory elements alloy barrier layer has the high potential for the future IC development because of its lower resistivity (117μΩ-cm) and nanocrystalline structure.
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