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Spectroscopic ellipsometry (SE) was employed to investigate the growth of atomic layer deposited (ALD) TiN thin films from titanium chloride (TinormalCl4) and ammonia (NnormalH3) and the followed oxidation in dry oxygen. Two regimes were found in the growth including a transient stage prior to a linear regime. The complementary ex situ characterization techniques showed a good agreement with the results obtained from SE measurements. A columnar structure of the as-deposited TiN film, which was composed of grains surrounded by amorphous material in between, was obtained. The X-ray photoelectron spectroscopy (XPS) analyses indicated low chlorine impurity content and slightly N-rich TiN films. The existence of an intermixed layer between the nitride and oxide during the oxidation was verified by the XPS depth profile analysis for a partially oxidized TiN film. A three-layer optical model was constructed for SE in situ monitoring the oxidation. A four-regime oxidation was found for 15-nm TiN films whereas only two regimes were seen in the case of 5-nm films. A new oxidation mechanism was proposed to explain the oxidation behavior of thin TiN films.

Articles you may be interested inDielectric properties of amorphous hydrogenated silicon carbide thin films grown by plasma-enhanced chemical vapor deposition Electrical conduction studies of plasma enhanced chemical vapor deposited silicon nitride films Low-temperature nitridation of silicon surface using NH 3 -decomposed species in a catalytic chemical vapor deposition system Characterization of fluorinated tetra ethyl ortho silicate oxide films deposited in a low pressure plasma enhanced chemical vapor deposition reactorThe results of a study on electrical conduction in low pressure chemical vapor deposited silicon nitride thin films for temperatures up to 650°C are described. Current density versus electrical field characteristics are measured as a function of temperature for 100 and 200 nm thick stoichiometric ͑Si 3 N 4 ͒ and low stress silicon-rich ͑SiRN͒ films. For high E-fields and temperatures up to 500°C conduction through Si 3 N 4 can be described well by Frenkel-Poole transport with a barrier height of ϳ1.10 eV, whereas for SiRN films Frenkel-Poole conduction prevails up to 350°C with a barrier height of ϳ0.92 eV. For higher temperatures, dielectric breakdown of the Si 3 N 4 and SiRN films occurred before the E-field was reached above which Frenkel-Poole conduction dominates. A design graph is given that describes the maximum E-field that can be applied over silicon nitride films at high temperatures before electrical breakdown occurs.

Carbon nanofibres (CNFs) and tungsten oxide (W18O49) nanowires have been incorporated into a continuous flow type microplasma reactor to increase the reactivity and efficiency of the barrier discharge at atmospheric pressure. CNFs and tungsten oxide nanowires were characterized by high-resolution scanning electron microscopy, transmission electron microscopy and nanodiffraction methods. Field emission of electrons from those nanostructures supplies free electrons and ions during microplasma production. Reduction in breakdown voltage, higher number of microdischarges and higher energy deposition were observed at the same applied voltage when compared with plane electrodes at atmospheric pressure in air. Rate coefficients of electron impact reaction channels to decompose CO2 were calculated and it was shown that CO2 consumption increased using CNFs compared with plane electrode in the microplasma reactor.

An analysis of the origin and passivation of interface states in (100)Si/SiO x /HfO 2 /TiN capacitor structures is presented. For highk gate/metal gate capacitors which exhibit relatively high interface state densities (> 1x10 11 cm -2 ) the dominant interfacial defects are silicon dangling bond (P bo ) centres. For (100)Si/SiO x /HfO 2 /TiN capacitors which experience no high temperature thermal budget following HfO 2 /TiN gate formation (T<600 o C), the devices exhibit instabilities, where the interface state densities are modified during electrical measurements. The origin of this instability is studied. The response of the interface state density to rapid thermal annealing (30s) in N 2 over the temperature range 600-900 o C is presented. In addition, results are presented for interface state passivation in forming gas (0.5H 2 /0.95N 2 ) from 350-550 o C for (100)Si/SiO x /HfO 2 /TiN gate stacks with no post deposition annealing following TiN gate formation and for devices following a 900 o C, 30s N 2 RTA.

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In this work, metal-insulator-metal (MIM) and metal-insulator-silicon (MIS) capacitors are studied using titanium nitride (TiN) as the electrode material. The effect of structural defects on the electrical properties on MIS and MIM capacitors is studied for various electrode configurations. In the MIM capacitors the bottom electrode is a patterned 100 nm TiN layer (called BE type 1), deposited via sputtering, while MIS capacitors have a flat bottom electrode (called BE type 2-silicon substrate). A high quality 50-100 nm thick SiO2 layer, made by inductively-coupled plasma CVD at 150 degrees C, is deposited as a dielectric on top of both types of bottom electrodes. BE type 1 (MIM) capacitors have a varying from low to high concentration of structural defects in the SiO2 layer. BE type 2 (MIS) capacitors have a low concentration of structural defects and are used as a reference. Two sets of each capacitor design are fabricated with the TiN top electrode deposited either via physical vapour deposition (PVD, i.e., sputtering) or atomic layer deposition (ALD). The MIM and MIS capacitors are electrically characterized in terms of the leakage current at an electric field of 0.1 MV/cm (I leak) and for different structural defect concentrations. It is shown that the structural defects only show up in the electrical characteristics of BE type 1 capacitors with an ALD TiN-based top electrode. This is due to the excellent step coverage of the ALD process. This work clearly demonstrates the sensitivity to process-induced structural defects, when ALD is used as a step in process integration of conductors on insulation materials.

Test structures for the electrical characterization of ultrathin conductive (ALD) films are presented based on buried electrodes on which the ultrathin film is deposited. This work includes test structure design and fabrication, and the electrical characterization of ALD TiN films down to 4 nm. It is shown that these structures can be used successfully to characterize sub 10 nm films.