Surface roughness and residual stress evolution in SiNx/ SiO2 multilayer coatings deposited by reactive pulsed magnetron sputtering (original) (raw)
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In this paper designing, preparation and characterization of multifunctional coatings based on TiO 2 /SiO 2 has been de− scribed. TiO 2 was used as a high index material, whereas SiO 2 was used as a low index material. Multilayers were deposited on microscope slide substrates by microwave assisted reactive magnetron sputtering process. Multilayer design was opti− mized for residual reflection of about 3% in visible spectrum (450-800 nm). As a top layer, TiO 2 with a fixed thickness of 10 nm as a protective film was deposited. Based on transmittance and reflectance spectra, refractive indexes of TiO 2 and SiO 2 single layers were calculated. Ultra high vacuum atomic force microscope was used to characterize the surface proper− ties of TiO 2 /SiO 2 multilayer. Surface morphology revealed densely packed structure with grains of about 30 nm in size. Pre− pared samples were also investigated by nanoindentation to evaluate their protective performance against external hazards. Therefore, the hardness of the thin films was measured and it was equal to 9.34 GPa. Additionally, contact angle of prepared coatings has been measured to assess the wetting properties of the multilayer surface.
Effect of oxygen to argon ratio on the properties of thin SiO x films deposited by r.f. sputtering
Journal of Materials Science: Materials in Electronics, 2010
Energy Dispersive X-ray and X-ray Photoelectron (XPS) spectroscopies show that SiO x films deposited by reactive r.f. magnetron sputtering at partial pressure ratios R between oxygen and argon in a wide range (1-0.005) have compositions close to the stoichiometric one. For these films high temperature annealing at 1,000°C shifts the band in the Fourier Transform-Infrared spectrum due to the Si-O-Si stretching vibration to values typical of stoichiometric SiO 2 . Further decrease of R leads to splitting of the Si 2p XPS line indicating increase of the Si content and formation of a second phase in a SiO 2 matrix. The electrical properties of test MOS structures with SiO x gate dielectric, regarding defect density in the oxide and at the SiO x /c-Si interface, degrade with the decrease of R. High temperature annealing at 1,000°C strongly improves the properties of all films regarding leakage current and properties of the interface.
Journal of Physics-condensed Matter, 2002
Mo/Si multilayer (ML) mirrors play a decisive role in an extreme-ultraviolet (EUV) lithography process. In this study, the surface and interfacial roughness, as well as the lateral and vertical correlation lengths, of a series of Mo/Si MLs deposited by RF-magnetron sputtering (RF-MS) have been characterized using diffuse x-ray scattering and atomic force microscopy. We have investigated the influence of the substrate quality and material (silicon, ule and zerodur) on the propagation and the value of ML roughness. We show that, whatever the substrate is, the film deposited by RF-MS presents a reduced roughness compared with that of the substrate. Moreover, rocking-curve analyses show that, for Si and ule substrates, the ML average roughness is very low (< 1.5 Å), associated with high spatial frequency oscillations, while in the case of zerodur substrates, the roughness is significantly increased (> 2 Å), and the high spatial frequency oscillations are reduced. Finally, the combination of specular and non-specular small-angle x-ray results allows us to evaluate another key parameter, namely, the uncorrelated roughness which is an intrinsic characteristic related to the choice of both the deposition technique and the materials. This intrinsic roughness is found to be very low (2 Å) and constitutes a good argument in favour of the use of the RF-MS technique for EUV mirror deposition.
Surface and Coatings Technology, 2007
In the present work SiC and B 4 C monolayers as well as SiC/B 4 C multilayer coatings have been investigated with respect to their composition and mechanical properties. The coatings have been deposited on silicon substrates and polished cemented carbide inserts by non-reactive dual radio frequency (r.f.) magnetron sputtering from stoichiometric, high-purity silicon carbide (99.5%) and boron carbide (99.9%) targets. Amorphous stoichiometric SiC and B 4 C have been achieved with high hardness of 2950 HV0.01 and 4160 HV0.01 with a residual stress of −3.4 GPa and −2.9 GPa, respectively. The number of monolayers in the multilayer system with a constant total layer thickness has been varied in order to investigate the influence of the number of interfaces on film composition and properties. Additionally, the monolayer thickness ratio for a constant modulation period (double layer thickness) was varied. In this multilayer system no notable hardness enhancement could be observed. Despite the absence of the hardness enhancement, the toughness is expected to be enhanced due to stress relaxation and a reduction of crack propagation by crack dissipation along the interfaces. An abrupt interface is considered to be an indispensable requirement. However, the strain fields and the difference of the mechanical properties in the interfacial region are also of importance.
Microstructural and mechanical properties of sputter deposited TiN/SiN x multilayer thin films
In this study, nanocomposite foams reinforced with different weight percentages of silicon dioxide nanoparticles (0.25, 0.5, 0.75 and 1.0 wt%) were fabricated using the ultrasonic and stir casting techniques. For this purpose heat treated TiH 2 was used as foaming agent. Microstructural studies were done by optical microscope and scanning electron microscope. Hardness evaluation of precursor nanocomposites showed that the hardness was significantly increased by the addition of SiO 2 nanoparticles and Al-0.75 wt% SiO 2 nanocomposite makes the highest hardness. Evaluation of compressive behavior of Al-SiO 2 nanocomposite foams showed that the plateau stress increases more than 3 times as the foam relative density increases from 0.09 to 0.16. Energy absorption of Al-SiO 2 nanocomposite foams has been found to be dependent on both relative density and structural properties.
2008
We present a complete systematic study on the effect of assist beam energy on SiO2/HfO2 quarter wave stacks deposited by dual ion beam sputter (DIBS) deposition. Increasing assist beam energy results in lower surface roughness and reduced micro-crystallinity. The coatings also show reduced mechanical stress. The improvements in the structural properties are accompanied by a reduction in the absorption loss and an increase in the laser resistance to damage at 1 μm.
An original approach for the fabrication of Si/SiO2 multilayers using reactive magnetron sputtering
Thin Solid Films, 2002
Composite and multilayered SiySiO structures have been grown by means of reactive magnetron sputtering of a pure silica 2 target. This method is based on the different nature of the plasma during deposition: the plasma consists of either pure argon or an argonyhydrogen mixture for the growth of silica or Si-rich films, respectively. Using this process, Si-rich single layers and Siy SiO multilayer structures have been successfully elaborated and characterised by infrared absorption spectroscopy, optical 2 transmission measurements and transmission electron microscopy (conventional and high resolution). The superlattices have shown a significant photoluminescence signal whose energy is governed by the Si sublayer thickness.
Surface and Coatings Technology, 2018
To withstand oxidation at a temperature ≥ 850 °C, an optimized Ti 1-x Al x N coating was grown via reactive High Power Impulse Magnetron Sputtering (HiPIMS) technology on three identical Ti 0.48 Al 0.48 Cr 0.02 Nb 0.02 billets. Different substrate surface pre-treatments were designed to increase performance: i) mechanical polishing, ii) mechanical polishing combined with a strong plasma etching, and iii) mechanical polishing coupled to both a weak plasma etching and a Ti 1-y Al y metallic interlayer deposition. Then, all the specimens were cyclically heat treated up to 200 cycles at 950 °C, using a Burner Rig (BR) facility. The chosen Ti 1-x Al x N/substrate interface architecture considerably influenced average compressive residual stress (S res) and adhesion of just deposited films. Moreover, it was possible to identify a clear relationship between S res behavior and each coating comportment after BR tests. It became clear that the weak plasma etching/Ti 1-y Al y interlayer match helped improving the system stability (i.e. very low average residual stress thermal relaxation) thus guarantying high temperature oxidation resistance.
Microelectronics Reliability, 2007
The substitution of the SiO 2 gate oxide in MOS devices by a material with a high-k dielectric constant is being deeply studied nowadays to solve the problem of the leakage currents that appear with the progressive scaling of SiO 2 thickness. To improve the quality of the high-k/Si interface a very thin SiO 2 film is grown between both materials. In this work, HfO 2 /SiO 2 stacks with different SiO 2 thickness were subjected to different types of stress (static and dynamic) to analyze the effect of this interfacial layer of SiO 2 in the degradation of the stack. The results show that the dielectric degradation depends on the stress applied and that the thickness of the SiO 2 interfacial layer influences the advanced stages of the stack degradation.
Tribology Letters, 2012
The tribological behavior of carbon/silicon bi-layer coatings deposited on a silicon substrate by DC magnetron sputtering was assessed and compared to that of amorphous carbon and silicon coatings. The motivation was to develop a wear resistant coating for silicon using thin layers of amorphous carbon and silicon. Wear tests were conducted by sliding a stainless steel ball against the coating specimens under applied normal loads in the range of 20 * 50 mN. Results showed that the wear rate of the bi-layer coating was strongly dependent on the ratio of thickness between the carbon and silicon layers. The wear rate of the bi-layer coating with 25 nm thick carbon and 102 nm thick silicon layers was about 48 and 20 times lower than that of the single-layer amorphous carbon and amorphous silicon coating, respectively. In addition, the steady-state friction coefficient of the bi-layer coating could be decreased to 0.09 by optimizing the thickness of the layer. Finally, a model for the wear reduction mechanism of the carbon/silicon bi-layer coating was proposed.