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Multilayer diffusion barrier for copper metallization using a thin interlayer metal ( M = Ru , Cr, and Zr) between two TiN films

Thin textured titanium nitride (TiN) films with thicknesses under 100 nm were grown on (100) silicon wafers by employing a radio-frequency generator to sputter reactively a Ti target under poisoned modes in mixtures of fixed Ar (3.6×10−1 Pa) and N2 at various partial pressures. The texture of the TiN films can be tailored by appropriately controlling the partial pressure of the reactive nitrogen. (111) textured films can be deposited over a broad range of lower N2 partial pressures from 2.9×10−2 to 1.8×10−1 Pa, while (100) textured films can be deposited in a narrow range of higher nitrogen partial pressures (2.3×10−1 to 3.3×10−1 Pa). The texturing effect is accounted for by a previously described thin film deposition mechanism. Scanning electron and atomic force microscopies demonstrate that the two textured TiN films both exhibit a column-grained structure; the columnar size of the (111) oriented TiN (⩾30 nm) is coarser than that of the (100) oriented TiN (10–20 nm). Evaluations of the textured TiN barriers, based on differences in sheet resistance, surface morphology, and phase transformation induced by annealing Si/TiN(40 nm)/Cu(200 nm) samples, suggest that the (111) TiN is a superior diffusion barrier material for copper than (100) TiN. The difference in barrier effectiveness is attributed to variations in crystallographic packing and microstructure of the textured diffusion barrier.

Deposition of polycrystalline lithium transition metal oxide thin films has been performed using radio frequency magnetron sputter deposition on indium tin oxide substrates. Different substrate temperatures, up to 500°C, were applied during deposition. The films deposited at elevated temperature exhibited a strong texture ͑or preferred orientation͒. It was found that varying the substrate temperature resulted in changing film texture. As the substrate temperature increased, the film structure changed from noncrystalline to polycrystalline with enhanced texture. The film texture and crystallography were examined using X-ray diffraction and transmission electron microscopy. The cross section and surface morphology were observed using scanning electron microscopy. The compositions of the targets and films were characterized by inductively coupled plasma spectroscopy. The deposition technique was used to prepare textured LiCoO 2 , LiNiO 2 , LiNi 0.8 Co 0.2 O 2 , and LiMn 2 O 4 thin films. The change of texturing can be interpreted by volume strain energy and surface energy minimization. Film texture of lithium transition metal oxide thin films can be controlled by the substrate temperature.

Epitaxial CuInSe 2 and Cu 1 In 3 Se 5 films have been synthesized on GaAs͑001͒ by cosputtering Cu/ In and evaporating Se method. Scanning electron micrograph results show that surface morphologies of CuInSe 2 and Cu 1 In 3 Se 5 epitaxial films are substantially different. The rectangular pits of CuInSe 2 films imply that the surface energy of ͑112͒B͓Se-terminated͔ is lower than ͑112͒A͓metal-terminated͔ in chalcopyrite CuInSe 2 crystals. Nevertheless, the square pits of the Cu 1 In 3 Se 5 films lead to the conclusion that ͑112͒A and ͑112͒B have almost the same surface energies in the defect-ordered chalcopyrite Cu 1 In 3 Se 5 crystals. It implies that charge compensation between ͑112͒A and ͑112͒B facets is the driving force of the square pits formation in Cu 1 In 3 Se 5 crystals.