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We investigated the thermal and plasma-enhanced atomic layer deposition ͑PE-ALD͒ of tantalum and titanium oxides from representative alkylamide precursors, Ta͑NMe 2 ͒ 5 ͑pentakis͑dimethylamino͒Ta, PDMAT͒ and Ti͑NMe 2 ͒ 4 ͓tetrakis͑dimethylami-do͒Ti, TDMAT͔. ALD of Ta 2 O 5 by PDMAT with water or oxygen plasma produced pure Ta 2 O 5 films with good self-saturation growth characteristics. However, incomplete self-saturation was observed for TiO 2 ALD from TDMAT. The film properties including microstructure, chemical composition, and electrical properties are discussed focusing on the comparative studies between thermal and PE-ALD processes for both oxides. The results indicate that the PDMAT is a promising precursor for both thermal and PE-ALD of Ta 2 O 5 .Atomic layer deposition ͑ALD͒ is a gas-phase thin-film deposition method characterized by the alternate exposure of chemical species with self-limiting surface reactions, producing films with accurate thickness control, excellent conformality, and uniformity over large areas. 1 Due to these benefits, ALD is becoming one of the most promising thin-film deposition methods in the fabrication of nanoscale microelectronic devices, for which thickness controllability at atomic level and high conformality are required. 2 One of the critical issues for a successful ALD process is a proper selection of precursors and reactants. Among many metal precursors, alkylamide precursors have been widely used for ALD since they have suitable vapor pressure and Cl-and O-free ligands producing noncorrosive products and require relatively low growth temperatures.ALD of high-k dielectrics have been extensively studied using a variety of precursors and reactants. 3-6 As representative high k oxides, Ta 2 O 5 and TiO 2 have been studied for various applications including capacitor and gate dielectrics for the semiconductor industry and chemical sensors. 7,8 Although various precursors have been studied for ALD of Ta and Ti-based materials, 4,9-12 alkylamide precursors have been widely used for deposition of TaN 13 or TiN. 14 For example, plasma-enhanced ALD ͑PE-ALD͒ of TaN from ͑pentakis-͑dimethylamino͒Ta ͑PDMAT͒ and hydrogen plasma produced good quality TaN, showing very robust characteristics as a diffusion barrier for Cu interconnects. 13 However, the alkylamide precursors have rarely been used for deposition of Ta or Ti oxide, except in a couple of very recent reports. 15,16 This is quite contrary to other high-k materials such as ZrO 2 and HfO 2 , for which extensive studies have been reported by thermal and PE-ALD from various alkylamide precursors. 17-20 Especially, no comparative study between thermal and PE-ALD from alkylamide precursors for Ta and Ti oxides has been reported yet. In this study, we investigated the thermal and PE-ALD processes of both oxides using representative alkylamide precursors, Ta͑NMe 2 ͒ 5 ͓pentakis͑dimethylamino͒Ta, PDMAT͔ and Ti͑NMe 2 ͒ 4 ͓tetrakis͑dimethylamido͒Ti, TDMAT͔, which have the same dimethylamino ligands. The film properties including micros...

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The growth mechanisms and film properties of atomic layer deposition ͑ALD͒ Ta-based thin films were investigated from alkylamide precursor ͓Ta͑NMe 2 ͒ 5 , ͑PDMAT͔͒. The reactions of PDMAT with various reactants including water, NH 3 , oxygen, and hydrogen plasma were studied and the resulting film properties were investigated by various analysis techniques. For TaN ALD from NH 3 and H plasma, the films were contaminated by considerable amount of carbon, while the Ta 2 O 5 deposited from water and O plasma were quite pure. Also, nitrogen was incorporated for ALD from PDMAT and H plasma, while no nitrogen incorporation was observed for O-plasma based plasma enhanced-ALD of Ta 2 O 5 except at high deposition temperature over 300°C. The results were comparatively discussed focusing on the differences in growth mechanism depending on reactants.

Highly conductive indium oxide films, electrically more conductive than commercial sputtered indium tin oxide films films, were deposited using a new liquid precursor Et2InN(SiMe3)2 and H2O by atomic layer deposition (ALD) at 225-250 °C. Film resistivity can be as low as 2.3 × 10(-4)-5.16 × 10(-5) Ω·cm (when deposited at 225-250 °C). Optical transparency of >80% at wavelengths of 400-700 nm was obtained for all the deposited films. A self-limiting ALD growth mode was found 0.7 Å/cycle at 175-250 °C. X-ray photoelectron spectroscopy depth profile analysis showed pure indium oxide thin film without carbon or any other impurity. The physical and chemical properties were systematically analyzed by transmission electron microscopy, electron energy loss spectroscopy, X-ray diffraction, optical spectrometer, and hall measurement; it was found that the enhanced electrical conductivity is attributed to the oxygen deficient InOx phases.

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We investigated transparent conducting aluminium-doped zinc oxide thin films fabricated by atomic layer deposition (ALD). For the thermal ALD, diethylzinc and trimethylaluminium were used as the Zn and Al precursors, respectively. The electrical, structural and optical properties were systematically investigated as functions of the Al doping contents and deposition temperature. The best resistivity and transmittance (4.2 m cm and ∼85%) were observed at an Al doping concentration of about 2.5 at% at 250 • C. An increase in the carrier concentration was observed with increasing deposition temperature and doping concentration. This can be explained by the effective field model of layered structures. Also, the enhancement of the mobility with increasing doping concentration was studied by the grain-boundary scattering and percolative conduction mechanism. By correlating the electrical and structural properties, it was found that varying the carrier concentration was more effective in changing the mobility than the grain-boundary scattering, due to the hopping conduction.