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The thermal properties of Cu(Ti)/SiO 2 and Cu(Zr)/SiO 2 systems have been investigated to evaluate the potential application for Cu metallization. Cu(Ti) and Cu(Zr) alloy films were directly deposited on SiO 2 /Si substrates and subsequently annealed in vacuum at various temperatures of 300°C–700 °C for 1 h. The microstructure, interface characteristics, and electrical properties of both samples were measured using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), transmission electron microscope (TEM) and leakage currents detector. Results suggest that Cu alloy films have strong Cu(111) texture after the addition of a small amount of Zr or Ti．The sharp decline of Cu and Si concentrations at the interface suggest that both Ti and Zr addition can prevent the inter-diffusion between Cu and substrate. The leakage current densities of Cu(Zr) and Cu(Ti) show that Zr is more stable element to self-forming diffusion layer for advanced Cu interconnects. [ABSTRACT FROM AUTHOR]

The properties of Cu(V) alloy films were investigated to evaluate its potential use as self-forming diffusion barrier in copper metallization. Cu(V) alloy films were deposited on SiO 2 /Si substrates by magnetron sputtering. Cu(V)/SiO 2 /Si systems were subsequently annealed at various temperatures and analyzed by four-point probe measurement (FPP), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM). After annealed at 500 °C, the resistivity of the Cu(V) films reduced to 3.1 μΩ cm, there is no obvious increase in resistivity. XRD suggest that Cu alloy film has preferential (111) crystal orientation and no extra peak corresponding to Cu and Si even after annealed at 500 °C. According to TEM results, a self-formed thin layer with the thickness of about 8 nm is observed at the interface between Cu alloy and the SiO 2 /Si substrate in the sample annealed at400 °C. As XPS results, after annealed at 400 °C and 500 °C, V atoms are observed at the surface of the Cu(V) films and the interface of the Cu(V) and SiO 2 /Si. The formation of the self-formed thin layer is probably due to the separation of V at the interface. The sharp declines of the Cu and Si concentrations at the interface indicate a lack of inter-diffusion between Cu and SiO 2 /Si. Adding small amounts of V to Cu film can improve the barrier performance and thermal stability compared with pure Cu contact systems. [ABSTRACT FROM AUTHOR]

A wealth of studies have confirmed that the low-field hysteresis behaviour of ferroelectric bulk ceramics and thin films can be described using Rayleigh relations, and irreversible domain wall motion across the array of pining defects has been commonly accepted as the underlying micro-mechanism. Recently, HfO2 thin films incorporated with various dopants were reported to show pronounced ferroelectricity, however, their microscopic domain structure remains unclear till now. In this work, the effects of the applied electric field amplitude, frequency and temperature on the sub-coercive polarization reversal properties were investigated for 10 nm thick Si-doped HfO2 thin films. The applicability of the Rayleigh law to ultra-thin ferroelectric films was first confirmed, indicating the existence of a multi-domain structure. Since the grain size is about 20-30 nm, a direct observation of domain walls within the grains is rather challenging and this indirect method is a feasible approach to resolve the domain structure. (© 2015 WILEY-VCH Verlag GmbH &Co. KGaA, Weinheim) [ABSTRACT FROM AUTHOR]

TiN films were fabricated on glass substrate by a vacuum kinetic spray method to investigate the effect of process gas flow rate, which determines particle velocity, on coating microstructure, and the mechanical properties of the resultant films. The as-fabricated microstructure of the films was studied by x-ray diffraction, field emission scanning electron microscopy, transmission electron microscopy (TEM), and high resolution TEM. Furthermore, nanoindentation and scratch tests were conducted to measure microhardness and adhesion strength, respectively. As the gas flow rate increased, damage, including lattice collapse and distortion, internal dislocation activation, and amorphization of the coating layer, increased. Simultaneously, the film not only become more compact with relatively finer grains, but also showed high hardness and great adhesive strength, which we attributed to consolidation during the deposition process. [ABSTRACT FROM AUTHOR]

Polarization switching and energy storage properties of highly (100) oriented antiferroelectric (AFE) (Pb,La)(Zr,Ti)O3 thin films (≤250 nm) deposited via a sol-gel process with both LaNiO3 and Pt top electrodes were investigated. By using LaNiO3 top electrodes, the energy density as well as energy efficiency can be enhanced by 4.6 J/cm3 and 11%, respectively. Furthermore, the films with LaNiO3 top electrodes are more capable of providing high energy density over a wide temperature regime above room temperature compared to Pt. This work clearly highlights that oxide top electrodes can greatly improve the energy storage performance of antiferroelectric thin film capacitors. [ABSTRACT FROM AUTHOR]

Abstract: The properties of Cu–Zr and Cu–Ru alloy films were comparatively studied to evaluate their potential use as alloying elements. Cu alloy films were deposited on SiO2/Si substrates by magnetron sputtering. Samples were subsequently annealed and analyzed by four-point probe measurement, X-ray diffraction, X-ray photoelectron spectroscopy, transmission electron microscopy and Auger electron spectroscopy. X-ray diffraction data suggest that Cu film has preferential (111) crystal orientation and no extra peak corresponding to any compound of Cu, Zr, Ru, and Si. According to transmission electron microscopy results, Cu grains grow in size for both systems but the grain sizes of the Cu alloy films are smaller than that of pure Cu films. These results indicate that Cu–Zr film is suitable for advanced barrier-free metallization in terms of interfacial stability and lower resistivity. [Copyright &y& Elsevier]

Abstract: A barrierless metallization scheme was proposed using Cu-based materials with enhanced thermal stability. Cu(Zr–N) films were deposited on Si substrates by magnetron sputtering and annealed at temperature up to 500°C in vacuum. The beneficial effects of a minor insoluble Zr–N on the grain refinement and thermal stability improvement were confirmed. By doping insoluble Zr–N into pure copper, some of the additive atoms precipitate at the grain boundaries, which can block the path of diffusion between copper and silicon, and inhibit the interaction between copper and silicon. In addition, ZrO2 or Zr(N,O) development near the Cu(Zr–N)/Si interface during annealing also contributes to the thermal stability of Cu(Zr–N)/Si samples. The results of X-ray diffraction, transmission electron microscopy, X-ray photoelectron spectroscopy and sheet resistance measurement show that Cu(Zr–N) seed layers has better thermal stability after 500°C annealing and is suitable for advanced barrierless metallization. [Copyright &y& Elsevier]

Abstract: Films of Cu–Ru–Zr and Cu–Zr were deposited on SiO2/Si substrates by magnetron sputtering. Samples were subsequently annealed at temperatures of up to 500°C for 1h and analyzed by four-point probe measurement, X-ray diffraction (XRD), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and Auger electron spectroscopy. The XRD data suggest that the Cu film has a preferential (111) crystal orientation. According to the TEM results the grain size of the alloy Cu film is smaller than that of a pure Cu film. XPS indicates that a ZrO x layer has formed at the Cu alloy/SiO2 interface and that its thickness in the annealed Cu–Ru–Zr/SiO2/Si sample becomes larger due to Ru incorporation. After annealing the resistivity values of the annealed Cu alloy films are a little higher than that of annealed pure Cu film. These results indicate that Cu–Ru–Zr films are suitable for advanced barrier-free metallization from the view of interfacial stability and low resistivity. [ABSTRACT FROM AUTHOR]

Abstract: Zr–Ti–N film prepared by sputtering deposition has been employed as a potential diffusion barrier for Cu metallization. It is thought that the existing states of Ti and Zr in the films are Ti–N and Zr–N phase in Zr–Ti–N films. Material analysis by XRD, XPS and sheet resistance measurement reveal that the failure of Zr–N film is mainly due to the formation of Cu3Si precipitates at the Zr–N/Si interface by Cu diffusion through the grain boundaries or local defects of the Zr–N barrier layer into Si substrate. In conjunction with sheet resistance measurement, XRD and XPS analyses, the Cu/Zr–Ti–N/Si contact system has high thermal stability at least up to 700°C. The incorporation of Ti atoms into Zr–N barrier layer was shown to be beneficial in improving the thermal stability of the Cu/barrier/Si contact system. [Copyright &y& Elsevier]

Abstract: Barrier capability of Zr–Si diffusion barriers in Cu metallization has been investigated. Amorphous Zr–Si diffusion barriers were deposited on the Si substrates by RF reactive magnetron sputtering under various substrate temperatures. An increase in substrate temperature results in a slightly decreased deposition rate together with an increase in mass density. An increase in substrate temperature also results in grain growth as deduced from field emission scanning electron microscopy (FE-SEM) micrographs. X-ray diffraction (XRD) spectra and Auger electron spectroscopy (AES) depth profiles for Cu/Zr–Si(RT)/Si and Cu/Zr–Si(300°C)/Si samples subjected to anneal at various temperatures show that the thermal stability was strongly correlated with the deposition temperature (consequently different density and chemical composition etc.) of the Zr–Si barrier layers. ZrSi(300°C) with higher mass density make the Cu/Zr–Si(300°C)/Si sample more stable. The appearance of Cu3Si in the Cu/Zr–Si/Si sample is attributed to the failure mechanism which may be associated with the diffusion of Cu and Si via the grain boundaries of the Zr–Si barriers. [Copyright &y& Elsevier]

Abstract: Zr–N/Zr bilayered film as a diffusion barrier between Cu and Si is evaluated. The thermal stability of the diffusion barrier is investigated by annealing the Cu/Zr–N/Zr/Si samples in N2 for an hour. XRD, SEM and AES results for the above contact systems after annealing at 700°C show that Cu film has preferential (111) crystal orientation and no diffraction peaks of Cu3Si and a Cu–Zr–Si ternary compound are observed for all Cu/Zr–N/Zr/Si contact systems. In addition, the atomic distribution of Zr and Si is evident and grows with increasing temperature up to 700°C, which corresponds to the Zr–Si phase having low contact resistivity. Low contact resistivity and high thermal stability diffusion barrier can be expected by the application of the Zr–N/Zr bilayered film as a diffusion barrier between Cu and Si. [Copyright &y& Elsevier]

Abstract: Zr–N thin films as a barrier in Cu/Si contact were investigated. The Cu/Zr–N/Si specimens were prepared and annealed at temperatures up to 700°C in N2 ambient for an hour. Characterization of phase composition and crystallite structure of the barriers was performed by XRD, the film morphology was examined using atomic force microscopy (AFM), and the composition profiles of the as-deposited and annealed samples of Cu/Zr–N/Si were identified by Auger electron spectroscopy (AES). It is evident that the Zr–N film structure is very sensitive to the deposition conditions. Cu/Zr–N/Si contact systems showed better thermal stability so that the Cu3Si phase could not be detected. It is indicated from the comparison analysis results that the Zr–N film showed better thermal stability with increasing N2 flow ratio and/or negative substrate bias. [Copyright &y& Elsevier]

The effectiveness of ZrSiN/Zr bilayered films to serve as diffusion barriers in Cu/Si contacts has been investigated. Annealing studies for Cu/ZrSiN/Zr/Si contact systems were carried out in N2/H2(10%) ambient. X-ray diffraction data suggest that Cu film has preferential (111) crystal orientation and Cu silicide cannot be observed up to 700 °C. Scanning electron microscopy micrographs show that the Cu film was integrated and free from agglomeration after annealing at 700 °C. Auger electron spectroscopy depth profiles of the Cu/ZrSiN(10 nm)/Zr(20 nm)/Si samples have no noticeable change except Zr silicide grows with annealing temperature up to 700 °C. The results indicate excellent barrier property for ZrSiN(10 nm)/Zr(20 nm) bilayer structure for Cu metallization. [ABSTRACT FROM AUTHOR]

Abstract: The effect of substrate temperature on the thermal stability of Cu/Zr–N/Si contact systems was investigated. Zr–N films were deposited on the Si substrates by RF reactive magnetron sputtering under various substrate temperatures. Cu films were in-situ sputtered onto the Zr–N films subsequently. The contact systems were characterized using four-point probe sheet resistance measurements (Rs), X-ray diffraction (XRD), and scanning electron microscopy (SEM) respectively. It was found that the sheet resistances of Cu/Zr–N(350 °C)/Si contact system were lower than those of Cu/Zr–N(150 °C)/Si specimens after annealing at 650 °C. Cu/Zr–N(350 °C)/Si contact systems showed better thermal stability so that the Cu3Si phase could not be detected. It is indicated from the comparison analysis results that the Zr–N film showed better diffusion barrier performance deposited under higher substrate temperature. [Copyright &y& Elsevier]

Abstract: The Influence of density and crystalline structure on the barrier performances of Zr–N films in Cu/Si contact system has been investigated. Three kinds of reactively sputter-deposited Zr–N films were prepared onto the Si substrates. Annealing studies for Cu/Zr–N/Si were carried out to investigate diffusion barrier performances of Zr–N films. The Cu/Zr–N/Si contact system was characterized by using four-point probe sheet resistance measurements, X-ray diffraction, and Auger electron spectroscopy respectively. It is indicated from the comparison studies that a combination of preferred crystalline structure with higher density may be responsible for the barrier capability of Zr–N films. [Copyright &y& Elsevier]

In this work, Pb 1−3 x /2 La x ZrO 3 (x = 0–0.12) (PLZ- x) antiferroelectric thin films were fabricated on Pt(111)/TiO 2 /SiO 2 /Si substrates using chemical solution method. Smaller cations (La3+) and vacancies were introduced into A-sites of perovskite structure to construct chemical pressure. According to phenomenological theory, chemical pressure can increase the energy barrier between antiferroelectric (AFE) and ferroelectric (FE) phase, and enhance antiferroelectricity of the system. As a result, a large energy storage density (W re) of 23.1 J cm−3 and high efficiency (η) of 73% were obtained in PLZ-0.10 films, while PLZ-0 films displayed lower W re (15.1 J cm−3) and η (56%). More importantly, PLZ-0.10 films exhibited an excellent cycling stability with a variation of ˜2% after 1 × 108 cycles. The results demonstrate that heavily La-doped PbZrO 3 films with high energy storage density, high efficiency and excellent cycling stability can be considered as potential candidates for energy storage applications. [ABSTRACT FROM AUTHOR]

Abstract: Films of Cu/Cu(Ru) and Cu(Ru) were deposited on Si substrates by magnetron sputtering. Samples were subsequently annealed and analyzed by four-point probe (FPP) measurement, X-ray diffraction (XRD), transmission electron microscopy (TEM) and Auger electron spectroscopy (AES). After annealing at 500°C, resistivity values of both systems decrease, but the reduction is more significant for Cu(Ru). Moreover, the resistivity values of annealed Cu(Ru) film are still greater than those of annealed Cu/Cu(Ru) film. XRD data suggest that Cu/Cu(Ru) film has higher thermal stability and Cu silicide cannot be observed up to 500°C. According to TEM results, after annealing at 500°C, the grain size of the Cu(Ru) film is smaller than that of Cu/Cu(Ru) film. In conjunction with AES, XRD, TEM analyses and sheet resistance measurement, it indicates that Cu/Cu(Ru) seed layers are potentially good for advanced Cu interconnects from the views of interfacial stability and low resistivity. [Copyright &y& Elsevier]