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Through-silicon vias (TSV) will speed up interconnections between chips. Manufacturable and cost-effective TSVs will allow faster computer systems. In this paper, we report the successful formation of seed layers for plating copper TSVs with aspect ratios greater than 25:1. Following the rapid atomic layer deposition (ALD) of a conformal insulating layer of silica inside the silicon vias, manganese nitride (Mn4N) is deposited conformally on the silica surface by chemical vapor deposition (CVD). Mn4N forms an effective copper diffusion barrier and provides strong adhesion between the silica and the subsequently-deposited copper. Conformal copper or copper-manganese alloy films are then deposited by an iodine-catalyzed direct-liquid-injection (DLI) CVD process. Diffusion of manganese during post-deposition annealing further enhances the barrier and adhesion properties at the copper/dielectric interface, Chemistry and Chemical Biology

An interlayer of face centered cubic (fcc) Co4N has demonstrated significant improvements in adhesion between copper and diffusion barrier layers. This fcc phase of Co4N was prepared by chemical vapor deposition (CVD) using bis(N-tert-butyl-N′-ethyl-propionamidinato)cobalt(II) and a reactant mixture of NH3 and H2 at substrate temperatures from 100 to 180°C. The Co/N atomic ratio and the phase of cobalt nitride film can be modified by adjusting the ratio of NH3 and H2 in the gas feedstock. The cobalt nitride films prepared by CVD are smooth, highly conformal, and stable against intermixing with copper up to at least 400°C. This fcc cobalt nitride material has very strong adhesion to copper due to the small lattice mismatch (−1 to 2%) between \(fcc-Co_4N\) and fcc Cu. Copper wires should be stabilized against failure by electromigration when fcc cobalt nitride interlayers are placed between the copper and surrounding diffusion barriers., Chemistry and Chemical Biology, Engineering and Applied Sciences

Lanthanum-based ternary oxide \(La_xM_{2−x}O_3\) (M = Sc, Lu, or Y) films were deposited on HF-last Si substrates by atomic layer deposition. Both \(LaScO_3\) and \(LaLuO_3\) films are amorphous while the as-deposited \(La_xY_{2−x}O_3\) films form a polycrystalline layer/amorphous layer structure on Si. Transmission electron microscopy and electrical analysis show the absence of interfacial layers. The dielectric constants for \(LaScO_3\), \(LaLuO_3\), and \(La_{1.23}Y_{0.77}O_3\) films are \(\sim 23\), \(28 \pm 1\), and \(17 \pm 1.3\), respectively, with leakage current density up to 6 orders of magnitude lower than that of thermal \(SiO_2\) with the same effective oxide thickness. Conformal coating thickness is demonstrated on holes with aspect ratio \(\sim 80:1\)., Chemistry and Chemical Biology

Amorphous LaAlO3 films were deposited on hydrogen-terminated silicon substrates by atomic layer deposition (ALD) at 300 oC. The precursors were lanthanum tris(N,N'-diisopropylformamidinate), trimethylaluminum (TMA) and water. Capacitance-voltage measurements made on ALD MoN/LaAlO3/Si stacks showed humps especially at low frequencies. They were effectively removed by O2 treatment at 300 o C without affecting the dielectric constant (kappa~15). The O2 treatment can be carried out either after deposition of a LaAlO3 film, or after each ALD cycle. The O2 treatment also lowered the leakage current from 80 mA cm-2 to 1 mA cm-2 for EOT = 1.3 nm. This indicates that oxygen vacancies are the main defects in as-deposited LaAlO3. Oxygen treated LaAlO3 is one of the best candidates for future high-kappa dielectric material due to its low leakage, low defect density and abrupt interface with silicon., Chemistry and Chemical Biology