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This study explored the structural characteristics, mechanical properties, and oxidation behavior of W-enriched TaWSiN films prepared through co-sputtering. The atomic ratios [W/(W + Ta)] of the as-deposited films maintained a range of 0.77–0.81. The TaWSiN films with a Si content of 0–13 at.% were crystalline, whereas the film with 20 at.% Si was amorphous. The hardness and Young’s modulus of crystalline TaWSiN films maintained high levels of 26.5–29.9 GPa and 286–381 GPa, respectively, whereas the hardness and Young’s modulus of the amorphous Ta7W33Si20N40 films exhibited low levels of 18.2 and 229 GPa, respectively. The oxidation behavior of TaWSiN films was investigated after annealing at 600 °C in a 1%O2–Ar atmosphere, and cone-like Ta0.3W0.7O2.85 oxides formed and extruded from the TaWSiN films.

Aluminum nitride (AlN) is a semiconductor material possessing a hexagonal wurtzite crystal structure with a large band gap of 6.2 eV. AlN thin films have several potential applications and areas for study, particularly in optoelectronics. This research study focused on the preparation of Ni-doped AlN thin films by using DC and RF magnetron sputtering for optoelectronic applications. Additionally, a comparative analysis was also carried out on the as-deposited and annealed thin films. Several spectroscopy and microscopy techniques were considered for the characterization of structural (X-ray diffraction), morphological (SEM), chemical bonding (FTIR), and emission (PL spectroscopy) properties. The XRD results show that the thin films have an oriented c-axis hexagonal structure. SEM analysis validated the granular-like morphology of the deposited sample, and FTIR results confirm the presence of chemical bonding in deposited thin films. The photoluminescence (PL) emission spectra exhibit different peaks in the visible region when excited at different wavelengths. A sharp and intense photoluminescence peak was observed at 426 nm in the violet-blue region, which can be attributed to inter-band transitions due to the incorporation of Ni in AlN. Most of the peaks in the PL spectra occurred due to direct-band recombination and indirect impurity-band recombination. After annealing, the intensity of all observed peaks increases drastically due to the development of new phases, resulting in a decrease in defects and a corresponding increase in the crystallinity of the thin film. The observed structural, morphological, and photoluminescence results suggest that Ni: AlN is a promising candidate to be used in optoelectronics applications, specifically in photovoltaic devices and lasers.

Improvement in crystallinity was investigated by compensating for stoichiometric deviations of non-selenization processed Cu0.9In0.7Ga0.3Se2 (CIGS) thin films due to highly volatile Se by co-sputtering them with Te followed by rapid thermal annealing. The prepared CIGS:Te thin films did not show any linear correlation between the compositional ratio and the co-sputtering time of Te; however, the deviation parameter (Δs) from the stoichiometry and normalized stoichiometric deviations of Se + Te and In + Ga were largely consistent with the behavior of thin-film properties. The proposed method provides better crystallinity with a large grain size, clear grain boundaries, and low microstrain and dislocation density, resulting in a large volume of the unit cell. The CIGS:Te thin films used as absorbers show improved optical properties compared to the conventional CIGS thin films, with Eg = 1.548 eV. These results can advance the low-cost commercialization of the enhanced-efficiency CIGS:Te thin films without the selenization process.

This work focused on the microstructure and mechanical properties of (Mo, Hf)N coatings deposited by radio frequency reactive magnetron co-sputtering technique with input power modulation. The coating characteristics, including indentation hardness, modulus, and tribological behavior, were discussed in terms of deposition parameter, composition, phase, and microstructure. The (Mo, Hf)N thin films were fabricated at a fixed Ar/N2 inlet gas ratio of 12/8 sccm/sccm and modulated input powers. The input power of Mo was fixed at 150 W, while that of the Hf target was managed from 25 to 200 W. The deposition rate and the Hf content of the (Mo, Hf)N coatings increased with input power. The (Mo, Hf)N ternary nitride coatings showed a polycrystalline microstructure with B1-MoN(111), β-Mo2N (112), γ-Mo2N(111), (200), and MoN2(200) phases in X-ray diffraction patterns as input power modulation were 150/25 to 150/100 W/W. The multiple phase microstructure feature and detail crystal development were demonstrated through transmission electron microscopy. According to nanoindentation and wear test results, ternary (Mo, Hf)N coatings represented more improved mechanical characteristics than the MoN and HfN binary nitride films. The 150/100 W/W deposited (Mo, Hf)N coating exhibited a highest hardness of 22.5 GPa when Hf content was at 5.6 at.%. The superior anti-wear behavior of this film with least wear damage was observed as well. The multiphase and solid-solution strengthening of the (Mo, Hf)N coatings, i.e., a microstructure feature of mixed B1-MoN, β-Mo2N, γ-Mo2N, and MoN2 phases and Hf doping in MoN, were the responsible for the superior mechanical and tribological behavior for the (Mo, Hf)N coatings.

In this study, we investigated the structural properties of TeO2-ZnO (TZ) and TeO2-ZnO-Au (TZA) thin films sputtered under different oxygen concentrations and either annealed or not annealed at 325 °C in air for 10 or 20 h. The lattice changes of the tellurium oxide were shown to be inherent in the polymorph properties of the α and β phases. The β phase was formed for null oxygen flow and the α phase was formed for different oxygen flows (0.5–7.0 sccm) during TZ and TZA sputtering. Au was encountered in its single phase or as AuTe2. The annealing had very little influence on the α and β phases for both TZ and TZA. It is worth noting that SiO2 and orthotellurate anions are both formed for not-null oxygen flow. An electrochemical mechanism was proposed to explain the SiO2 growth at the TZ/Si or TZA/Si interface, taking the orthotellurate anion as oxidizing agent into account.

We demonstrate monocrystalline growth of GeSn on Ge and Si substrates by co-sputtering. We discuss the evolution of film growth with thickness, elucidating the effects of substrate temperature, sputtering source, and the importance of hydrogen dilution in the plasma.

A sneak path current—a current passing through a neighboring memory cell—is an inherent and inevitable problem in a crossbar array consisting of memristor memory cells. This serious problem can be alleviated by serially connecting the selector device to each memristor cell. Among the various types of selector device concepts, the diffusive selector has garnered considerable attention because of its excellent performance. This selector features volatile threshold switching (TS) using the dynamics of active metals such as Ag or Cu, which act as an electrode or dopant in the solid electrolyte. In this study, a diffusive selector based on Ag-doped HfOx is fabricated using a co-sputtering system. As the Ag concentration in the HfOx layer varies, different electrical properties and thereby TS characteristics are observed. The necessity of the electroforming (EF) process for the TS characteristic is determined by the proper Ag concentration in the HfOx layer. This difference in the EF process can significantly affect the parameters of the TS characteristics. Therefore, an optimized doping condition is required for a diffusive selector to attain excellent selector device behavior and avoid an EF process that can eventually degrade device performance.

The microstructures and mechanical behavior of high-temperature co-sputtered Cu/Mo nanocomposites were investigated and compared with Cu/Mo multilayers. The co-sputtered nanocomposites present hierarchical architectures with bicontinuous intertwined Cu/Mo phases, the feature size of which can be tuned from 35 to 3 nm by changing the deposition parameters. After indentation, shear bands were found in the multilayers but not in the hierarchical nanocomposites. In situ nanocompression tests in Transmission electron microscopy showed that the hierarchical nanocomposite containing fine-length-scale intertwined Cu/Mo phases has very high strength. The hierarchical structure is proposed to play an important role in suppressing shear band formation. Impact statement Cu/Mo nanocomposites with novel hierarchical architecture containing bicontinuous intertwined structures were fabricated through co-sputtering. High strength and good deformability were achieved in the nanocomposites through in situ nanomechanical testing.

International audience; Skutterudite CoSb3 material exhibits excellent thermoelectric properties for thermoelectric application. In this work, CoSb3 thin films were fabricated by direct current magnetron co-sputtering. The composition of thin films was controlled by regulating the deposition power of both Co and Sb. Then the as-deposited Sb-excess sample was chosen to process post-annealing. High-resolution transmission electron microscopy and X-ray diffraction, together with Raman analysis, demonstrate that the annealed samples have well-crystallized and nano-sized skutterudite CoSb3 structure. Hall measurement shows that specimens are P-type semiconductor. Both of the increasing of Seebeck coefficient and electric conductivity can be obtained when the samples annealed at appropriate temperature, indicating that thermally can improve its thermoelectric properties due to well-crystallized and nano-sized structure. © 2017 Elsevier B.V.

Titanium niobium mixed oxide films have been deposited by reactive magnetron serial co-sputtering. After post annealing at 650 °C in air, a monoclinic TiNb 2 O 7 phase was achieved. Lithium intercalation properties were determined and cathodic switching behavior has been demonstrated for this material. Maximum switching of the integral visual transmittance of 16.8% has been determined for this sample with a thickness of 156 nm.

In the present work, coatings in the material systems B-C-W and B-C-Ti have been synthesized by pulse magnetron sputtering, to exploit their potential as coatings for hard, wear resistant applications. These layers offer interesting properties, because of the possible amounts of carbides and borides that can form in the non-equilibrium deposition processes. Especially the amount of tungsten in the layers promises high wear resistance and corrosion protection at elevated temperatures. The B-C-W and B-C-Ti thin films have been deposited by pulsed magnetron co-sputtering in bipolar mode, using a boron carbide (B 4 C) target and a metal target (W or Ti) with a maximum total power input of 12.9 W/cm 2 . The amount of metal in the layers has been varied by adjusting the sputtering pulse length of the respective target material. The influence of bias voltage on the properties of B-C-W coatings has been investigated and it was found out that bias voltages of − 60 V … − 100 V lower the hardness of the coatings. The hardness and the Young's modulus of the layers have been determined by nanoindentation. Whereas the majority of coatings exhibits hardness around 20 GPa or lower, maximum hardness of 28 GPa and Young's modulus of 420 GPa are observed in a certain compositional range, in which coatings also distinguish by good thermal stability. Their composition has been analysed by using optical glow discharge emission spectroscopy (GD-OES) and Rutherford backscattering spectrometry (RBS).

ZnO p-type thin films were deposited by dual acceptor co-doping using nitrogen and silver via DC reactive magnetron co-sputtering. As precursor material were used a Zn and an Ag metallic targets with a purity of 99.99%. X-ray energy dispersive spectroscopy (EDX) confirmed the presence of Ag and N in ZnO: Ag,N films. The electrical properties were explored by Hall Effect measurement and showed a low hole concentration for the as-deposited ZnO: Ag,N film. However, after annealing treatment, the films remained p-type and the electrical properties were improved significantly. The best electrical properties showed a low resistivity of 8.56×10 Ωcm, Hall mobility of 23 cm/Vs and a very high hole concentration of 3.17×10 cm., This work was partially supported by Project CONACyT-105723.

A sneak path current—a current passing through a neighboring memory cell—is an inherent and inevitable problem in a crossbar array consisting of memristor memory cells. This serious problem can be alleviated by serially connecting the selector device to each memristor cell. Among the various types of selector device concepts, the diffusive selector has garnered considerable attention because of its excellent performance. This selector features volatile threshold switching (TS) using the dynamics of active metals such as Ag or Cu, which act as an electrode or dopant in the solid electrolyte. In this study, a diffusive selector based on Ag-doped HfOx is fabricated using a co-sputtering system. As the Ag concentration in the HfOx layer varies, different electrical properties and thereby TS characteristics are observed. The necessity of the electroforming (EF) process for the TS characteristic is determined by the proper Ag concentration in the HfOx layer. This difference in the EF process can significantly affect the parameters of the TS characteristics. Therefore, an optimized doping condition is required for a diffusive selector to attain excellent selector device behavior and avoid an EF process that can eventually degrade device performance.

In this study, amorphous indium gallium oxide thin-film transistors (IGO TFTs) were fabricated by co-sputtering. Three samples with different deposition powers of the In2O3 target, namely, sample A with 50 W deposition power, sample B with 60 W deposition power, and sample C with 70 W deposition power, were investigated. The device performance revealed that oxygen vacancies are strongly dependent on indium content. However, when the deposition power of the In2O3 target increased, the number of oxygen vacancies, which act as charge carriers to improve the device performance, increased. The best performance was recorded at a threshold voltage of 1.1 V, on-off current ratio of 4.5 × 106, and subthreshold swing of 3.82 V/dec in sample B. Meanwhile, the optical properties of sample B included a responsivity of 0.16 A/W and excellent ultraviolet-to-visible rejection ratio of 8 × 104. IGO TFTs may act as photodetectors according to the results obtained for optical properties.

ZnO films with Ti atoms incorporated (TZO) in a wide range (0&ndash, 18 at.%) have been grown by reactive co-sputtering on silicon and glass substrates. The influence of the titanium incorporation in the ZnO matrix on the structural and optical characteristics of the samples has been determined by Rutherford backscattering spectroscopy (RBS), X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD). The results indicate that the samples with low Ti content (&lt, 4 at.%) exhibit a wurtzite-like structure, with the Ti4+ ions substitutionally incorporated into the ZnO structure, forming Ti-doped ZnO films. In particular, a very low concentration of Ti (&lt, 0.9 at.%) leads to a significant increase of the crystallinity of the TZO samples. Higher Ti contents give rise to a progressive amorphization of the wurtzite-like structure, so samples with high Ti content (&ge, 18 at.%) display an amorphous structure, indicating in the XPS analysis, a predominance of Ti&ndash, O&ndash, Zn mixed oxides. The energy gap obtained from absorption spectrophotometry increases from 3.2 eV for pure ZnO films to 3.6 eV for those with the highest Ti content. Ti incorporation in the ZnO samples &lt, 0.9 at.% raises both the blue (380 nm) and green (approx. 550 nm) bands of the photoluminescence (PL) emission, thereby indicating a significant improvement of the PL efficiency of the samples.

In this study, we investigated the structural properties of TeO2-ZnO (TZ) and TeO2-ZnO-Au (TZA) thin films sputtered under different oxygen concentrations and either annealed or not annealed at 325 &deg, C in air for 10 or 20 h. The lattice changes of the tellurium oxide were shown to be inherent in the polymorph properties of the &alpha, and &beta, phases. The &beta, phase was formed for null oxygen flow and the &alpha, phase was formed for different oxygen flows (0.5&ndash, 7.0 sccm) during TZ and TZA sputtering. Au was encountered in its single phase or as AuTe2. The annealing had very little influence on the &alpha, phases for both TZ and TZA. It is worth noting that SiO2 and orthotellurate anions are both formed for not-null oxygen flow. An electrochemical mechanism was proposed to explain the SiO2 growth at the TZ/Si or TZA/Si interface, taking the orthotellurate anion as oxidizing agent into account.

Materials Research Express PAPER Influence of substrate temperature on CuxSnSx+1 thin films prepared by Co-sputtering and H2S annealing Yusuf Selim Ocak1,2 Published 15 January 2020 • © 2020 IOP Publishing Ltd Materials Research Express, Volume 6, Number 12 Citation Yusuf Selim Ocak 2019 Mater. Res. Express 6 126443 52 Total downloads 11 citation on Dimensions.Article has an altmetric score of 1 Turn on MathJax Get permission to re-use this article Share this article Share this content via email Share on Facebook (opens new window) Share on Twitter (opens new window) Share on Mendeley (opens new window) Article information Abstract CuxSnSx+1 (CTS) thin films were deposited by co-sputtering of Cu and Sn targets and annealing the films in an Ar:H2S atmosphere. The substrate temperatures were fixed at room temperature, 100, 175, and 250 °C during film deposition. The deposited films were then annealed in an Ar:H2S atmosphere at 550 °C for 1 h. The Cu/Sn ratio decreased sharply with substrate temperature. In the annealed samples, the Cu/Sn ratio increased for films deposited at room temperature, 100, and 175 °C, and decreased for films deposited at 250 °C, showing the temperature dependence of CuxSn alloy formation. Additionally, Cu3SnS4 phase formation was observed in the films grown at room temperature, whereas the films showed a Cu2SnS3 phase at higher substrate temperatures.

Nb-doped ZnO thin films were fabricated on glass substrates by using co-sputtering with direct-current and radio frequency magnetron sputtering. The structures, optical and electrical performances of Nb-doped ZnO thin films were investigated. The results showed that all thin films have (0 0 2) [Formula: see text]-axis preferential orientation. The minimum resistivity of [Formula: see text][Formula: see text]cm and the maximum carrier concentration of [Formula: see text][Formula: see text][Formula: see text] were obtained at the direct-current sputtering power of 10[Formula: see text]W, respectively. Nb-doped ZnO thin films have also shown high average transmittance of 89.6%, and lower surface roughness of 2.74[Formula: see text]nm. Meanwhile, a distinct absorption edge in the ultraviolet range of 300–400[Formula: see text]nm was observed in absorbance, the optical band gap of Nb-doped ZnO thin films illustrates an increased tendency with increasing Nb concentration.

Alloying of Cu2ZnSnS4 (CZTS) with Ge can potentially promote grain growth and suppress the formation of Sn‐related defects. Herein, a two‐step fabrication route based on compound co‐sputtering and sulfurization at a high temperature is used to prepare Ge‐incorporated CZTS (Cu2ZnGexSn1 − xS4 [CZGTS]). For Cu2ZnGeS4 (CZGS), films deposited using elemental Ge and binary GeS targets are compared. The recrystallization is shown to be promoted for the absorbers deposited using Ge target, possibly due to lower sulfur content in the precursor suppressing the formation of wurtzite‐like phases during sputtering. The grain growth and crystallinity in CZGTS are slightly improved for x = 0.2 but not for higher concentration of the incorporated Ge. Owing to the composition‐dependent electronic properties, compositionally graded CZGTS films may be beneficial for reducing recombination towards the back contact. Hence, herein, the successful formation of a steep concentration gradient with Ge and Sn is demonstrated by the deposition of a CZGS/CZTS precursor stack followed by sulfurization with varying time periods.

International audience; The unique properties of amorphous chalcogenides such as wide transparency in the infrared region, low phonon energy, photosensitivity and high linear and nonlinear refractive index, make them prospective materials for photonics devices. The important question is whether the chalcogenides are stable enough or how the photosensitivity could be exacerbated for demanded applications. Of this view, the Ge-Sb-Se system is undoubtedly an interesting glassy system given the antinomic behavior of germanium and antimony with respect to photosensitivity. The amorphous Ge-Sb-Se thin films were fabricated by a rf-magnetron co-sputtering technique employing the following cathodes: GeSe2,Sb2Se3 and Ge28Sb12Se60. Radio-frequency sputtering is widely used for film fabrication due to its relative simplicity, easy control, and often stoichiometric material transfer from target to substrate. The advantage of this technique is the ability to explore a wide range of chalcogenide film composition by means of adjusting the contribution of each target. This makes the technique considerably effective for the exploration of properties mentioned above. In the present work, the influence of the composition determined by energy-dispersive X-ray spectroscopy on the optical properties was studied. Optical bandgap energy E-g(opt) was determined using variable angle spectroscopic ellipsometry. The morphology and topography of the selenide sputtered films was studied by scanning electron microscopy and atomic force microscopy. The films structure was determined using Raman scattering spectroscopy.

Magneto-optic (MO) garnets are used in a range of applications in nanophotonics, integrated optics, communications and imaging. Bi-substituted iron garnets of different compositions are the most useful class of materials in applied magneto- optics due to their excellent MO properties (large Faraday effect) and record-high MO figure of merit among all semi- transparent dielectrics. It is highly desirable to synthesise garnets which possess simultaneously a high MO figure of merit and large uniaxial magnetic anisotropy. However, the simultaneous optimization of several material properties and parameters can be difficult in single-layer garnet thin films, and it is also challenging to prepare films with high bismuth content using physical vapor deposition technologies. To meet the current challenge of developing next-generation functional MO materials, we design, develop and demonstrate the functionality of new magnetostatically-altered all-garnet multilayer heterostructures using two different garnet materials of dissimilar anisotropy types (out-of-plane and almost-in- plane). The multilayer structures possess simultaneously a high MO figure of merit and large uniaxial magnetic anisotropy together with low coercivity, if each of the layers is optimized in composition and annealed correctly. We prepare thin-film heterostructures by sandwiching a MO garnet layer with almost in-plane magnetization in-between two MO garnet layers with out-of-plane magnetization using RF sputtering. We apply customised high-temperature oven annealing processes (optimized in temperature and process durations after running many trials) for the as-deposited (amorphous) garnet multilayers to obtain the crystalline garnet phase in every layer. These structures then possess simultaneously a high optical/MO quality and low coercivity, which is very attractive for the development of magnetic photonic crystals, sensing devices and ultra-fast switches. Based on Bi-substituted ferrite garnets grown on garnet substrates, this new and unique method for the development of new magnetic materials, enables customized magnetic properties to be attained, and can be used to develop novel types of synthetic garnet materials.

Sn-DLC thin films were deposited by a dual magnetron sputtering system using a fixed DC power applied to a C target and a variable DC or HiPIMS power supply applied to a Sn target. Scanning electron microscopy (SEM) images showed the presence of larger Sn clusters on films deposited using HiPIMS compared with those deposited using DC power supply. The small resistivity of HiPIMS films can be related with the large Sn cluster and the elevated number of sp2 type bonding.

A new simple way for tuning the phase transition temperature (PTT) of VO2 thin films has been proposed to solve the problem of changing the doping ratio by using the dual-target co-sputtering method. A series of samples with W doping ratios of 0%, 0.5%, 1%, 1.5% and 2% have been fabricated by sputtering V films with the power of pure and 2% W-doped V targets from 500 W: 0 W, 500 W: 250 W, 500 W: 500 W, 250 W: 500 W to 0 W: 500 W respectively and then annealed in an oxygen atmosphere to form VO2. The XRD results of both pure and W-doped VO2 samples reveal that VO2 forms and is the main component after annealing. The PTT can be tuned by controlling the sputtering power ratio of the pure and doped targets. It can be tuned easily from 64.3 &deg, C to 36.5 &deg, C by using the pure and 2% W-doped targets for demonstration, with W doping ratios from 0% to 2%. It is also valid for other doping elements and is a promising approach for the large-scale production of sputtering.

In this study, amorphous indium gallium oxide thin-film transistors (IGO TFTs) were fabricated by co-sputtering. Three samples with different deposition powers of the In2O3 target, namely, sample A with 50 W deposition power, sample B with 60 W deposition power, and sample C with 70 W deposition power, were investigated. The device performance revealed that oxygen vacancies are strongly dependent on indium content. However, when the deposition power of the In2O3 target increased, the number of oxygen vacancies, which act as charge carriers to improve the device performance, increased. The best performance was recorded at a threshold voltage of 1.1 V, on-off current ratio of 4.5 &times, 106, and subthreshold swing of 3.82 V/dec in sample B. Meanwhile, the optical properties of sample B included a responsivity of 0.16 A/W and excellent ultraviolet-to-visible rejection ratio of 8 &times, 104. IGO TFTs may act as photodetectors according to the results obtained for optical properties.

Zn x Cd 1-x S thin films at low zinc content have been deposited on bare soda lime glass substrates using RF magnetron co-sputtering of CdS and ZnS for the first time to investigate annealing effect on the structural and optical properties of the thin films. The as-deposited films were annealed in O 2 /N 2 ambient at annealing temperature ranging 200-500 °C. The composition of the films was controlled by varying RF power of CdS and ZnS in such a ratio so that zinc content in the thin films was low. The composition, structural, optical and surface morphological properties of the films was investigated using EDX, XRD, UV-Vis spectrophotometer and FESEM. The annealed films were observed hexagonal wurtzite structure with strong preferential orientation along (002) diffraction peak. Crystallinity of the films increased with increasing annealing temperature below 400 °C whereas beyond 400 °C new peaks were observed along with decreasing trend of (002) diffraction peak. Optical absorption and transmission spectra were recorded within the range 300-900 nm. With increasing annealing temperature, the band gap of the annealed films once decreased and then abruptly increased at around 400 °C. The decreased bandgap may have been due to possible increase in the crystalline nature of the material. From SEM, it was observed that the thin films were formed by different clusters of grains which later changed to isolated grains as the annealing temperature increased. This work confirms that annealing temperature has overbearing influence on the Zn x Cd 1-x S thin film properties deposited by RF magnetron co-sputtering.

ZnMgO films were prepared at room temperature on freestanding diamond (FSD) substrates by co-sputtering. The Mg content was controlled by varying RF sputtering power of MgO and the effects of Mg contents on the properties of ZnMgO films were investigated. The results showed that the (0002) peak of ZnMgO shifted from 34.5° to 35.6° with the increasing sputtering power of MgO target. The UV-visible and PL spetra of ZnMgO films revealed that the bandgap of ZnMgO was approximately linear related to the sputtering power of MgO target.

The amorphous HfO2 doped Gd2O3 (GDH) film has been grown on p-type Si (001) substrates by radio frequency co-sputtering, and the thickness of GDH film was 4.4nm. The results of electrical tests showed that the ΔVFB of C-V curves reduced from 170mV to 40mV, dielectric constant increased from 19.6 to 21.3, and relaxation phenomena decreased after RTA. I-V curves showed that the leakage current density of GDH film was reduced from 9.6×10-4 A/cm2 to 1.3×10-5 A/cm2 after Rapid Thermal Annealing (RTA). The reliability studies on GDH gate dielectric show that the Time Zero Dielectric Breakdown (TZDB) was mainly caused by the accumulation of positive charges.

Amorphous silicon oxycarbonitride (SiC x N y O z ) films have been deposited on Si substrates by low temperature reactive magnetron co-sputtering of silicon and graphite targets in mixed Ar/N 2 atmosphere. Our studies are focused on the influence of nitrogen incorporation on deposition rate, film composition, film structure, chemical bonds, and electrical resistivity of SiC x N y O z films investigated by profilometry, Rutherford Backscattering Spectrometry (RBS), X-ray diffraction (XRD), Raman spectroscopy, X-ray Photoelectron Spectroscopy (XPS), and four-point probe method. RBS results show that all samples contain significant amounts of oxygen (up to 16 at.%) which led to the formation of SiC x N y O z . Further, XPS results show that most of this oxygen is located in the film surface. With the addition of N 2 gas in the plasma, the carbon, and nitrogen contents in the films increase. The increased carbon content is due to the contribution of chemically driven sputtering of the graphite target and the reduction of the sputtering rate of the silicon target owing to poisoning by nitrogen. Raman spectra suggest that the films contain amorphous phases and that the a-C clusters suffer a graphitization with increased N 2 gas flow rate. The XRD analysis confirmed the amorphous structure of these films. According to the XPS analysis, the increase in nitrogen content leads to an increase in Si N and C N bonds, decreasing the Si C, Si Si, and C C bonds. Finally, the films electrical resistivity depends mainly on the nitrogen content, which makes it possible to obtain semiconductor or insulator SiC x N y O z films only by adjusting the N 2 concentration in the gas phase during the deposition process.

Doping of TiO 2 – a wide band gap material - with Neodymium (Nd 3+ ) ions have been the focus of research interest for the solar spectrum downshifting, a process which can improve the efficiency of silicon based solar cells. This work presents the influence of varying Nd doping concentration in the range 1.17-25 at.% in the TiO 2 host matrix. Thin films of thickness between 1 - 2 μm were deposited by Radio-Frequency Co-Sputtering of TiO 2 and Neodymium (Nd) target on quartz and silicon substrates at room temperature. The films are annealed in an air ambient after deposition. Film properties were studied from the structural and chemical composition point of view by means of X-ray diffraction (XRD), Auger Electron Spectroscopy (AES). Two distinct photoluminescence emission peaks were observed at 902 and 1080 nm in the doped films, pertaining to the transitions between the excited levels 4 F 3/2 to 4 I 9/2 and 4 I 11/2 levels of the Nd 3+ ions by exciting at 514.5 and 355 nm.

International audience; We report a study of the influence of the deposition conditions on the morphological parameters (shapes, size distribution and ordering) of Ag nanoclusters embedded in SiO(2), deposited by different techniques of co-sputtering or multilayer deposition. The influence of the substrate temperature on the nucleation and growth process is also studied. The different cluster morphologies determined by various complementary techniques (transmission electron microscopy, scanning electron microscopy, atomic force microscopy) are then correlated with the optical absorption, showing that the fabrication process is the key factor to control the position, shape and width of the surface plasmon resonance peaks and to achieve the desired optical properties. Films deposited by co-sputtering from 2 targets on a substrate heated at 440 degrees C show a very narrow absorption peak at 370 nm corresponding to the plasma resonance in near spherical silver particles. In multilayered films, the absorption peak is shifted from 340 to 480 nm with a larger half-band width. In cermet films co-sputtered from composite target on a rotating substrate, two absorption peaks are observed due to the more elongated shape of the metal nanoparticles. The experimental results are analysed in the frame of the Maxwell Garnett theory. (C) 2009 Elsevier B.V. All rights reserved.

7th International Conference on Electrical Transport and Optical Properties of Inhomogeneous Media (ETOPIM-7), Sydney, AUSTRALIA, JUL 09-13, 2006; International audience; Nano-structures are not an invention of the 20th century. In Middle Age already, craftsmen were able to produce multi-layer structures of nano-particles at the surface of potteries creating lustres, this means potteries with shining effects. In order to study the optical properties of these objects and because, as a part of our patrimony, they cannot be destroyed, we decided to reproduce the structures observed by co-sputtering. Developing a model, we were able to predict the reflection spectrum of the created samples with a good accuracy, validating it. However, this work is a first experimental step and improvements are needed from both theoretical and experimental sides in order to understand fully the optical properties of the lustres. (c) 2007 Elsevier B.V. All rights reserved.

We have deposited various FeAg granular systems having different iron content and we have investigated their giant magnetoresistive properties as a function of temperature. In a previous work we observed that, at room temperature, with increasing Fe content samples behaviour changes from superparamagnetic to ferromagnetic-like, and 20% is the concentration that separates these two regimes. In correspondence with this value, the dependence of giant magnetoresistance intensity as a function of iron concentration shows a maximum. With decreasing temperature, we observed that the position of this maximum shifts progressively towards lower iron concentrations. This behaviour has been discussed in terms of the presence of magnetic interparticle interactions. An analysis of the dependence of giant magnetoresistance as a function of applied field at the various temperatures is also presented.

Ag–TaN sputtered on polyester (PES) accelerated >6 times the bacterial inactivation kinetics compared to TaN–PES under actinic light irradiation. Direct current pulsed magnetron sputtering (DCP) was used to sputter Ag–TaN–PES and TaN–PES. Complete bacterial reduction by Ag–TaN occurred within 20 min compared to Ag–TiN (100 min) and Ag–ZrN (90 min). The co-sputtering of Ag and Ta on PES was carried out in an Ar/N2 10% atmosphere. By ion-coupled plasma mass-spectrometry (ICP–MS) a reduced Ag-release was observed for Ag–TaN samples compared to Ag–PES samples within the disinfection period. The redox catalysis by the Ag-species during the bacterial disinfection was followed by X-ray photoelectron spectroscopy (XPS). A bacterial reduction mechanism is suggested consistent with the experimental findings. The nitride films were characterized by surface science methods.