Characterization of SiC Thin Films Deposited by HiPIMS

In this work thin films of silicon carbide (SiC) were deposited on silicon wafers by High Power Impulse Magnetron Sputtering (HiPIMS) technique varying the average power of the discharge on a stoichiometric SiC target. X-ray diffraction, Raman spectroscopy, scanning electron microscopy and profilometry were used to analyze the films. It was observed that high values of the average electric power favors the formation of C-C bonds, while low values of the power promote the formation of Si-C bonds. At high power, we have also observed higher deposition rates, but the samples present surface imperfections, causing increase in the roughness and decrease in the film uniformity.Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Inst Tecnol Aeronaut ITA, Ctr Tecn Aeroespacial CTA, BR-12228900 Sao Jose Dos Campos, SP, BrazilUniv Vale Paraiba, UNIVAP, BR-12244390 Sao Jose Dos Campos, SP, BrazilUniversidade Federal de São Paulo, UNIFESP, BR-12231280 Sao Jose Dos Campos, SP, BrazilUniversidade Federal de São Paulo, UNIFESP, BR-12231280 Sao Jose Dos Campos, SP, BrazilWeb of Scienc

A historical overview of the research on TiO2 thin films deposited by atomic layer deposition – Part I: Early Studies

<p>Molecular Layering (ML) or Atomic Layer Epitaxy (ALE) or Atomic Layer Deposition (ALD) technique is a gas-phase layer by layer deposition method which belongs to the general class of Chemical Vapor Deposition (CVD) techniques, and which has become of worldwide importance due to success in down-scaling of microelectronic devices. Among the materials obtained by the technique, titanium dioxide (TiO₂) stands out due to its crystallographic importance and numerous applications ranging from the photovoltaics to self-cleaning surfaces. Here we present an overview of the history of TiO₂ thin films grown by ALD technique organized into three periods: early studies (1960s-1990s), consolidation period (2000s) and current stage (2010-present). First, we report the early material synthesis and characterization studies on ALD TiO₂ thin films during the 4 decades between 1960s to 1990s. Then we address the evolution of the research field from the 2000s until the present day. The purpose of this historical survey is to synthetize the evolution of ALD TiO₂ thin films technology for different applications, which could be useful for students and researchers working in this field. In this manuscript, Part I is presented reporting the first published studies on TiO₂ thin films deposited by ALD. </p

Macrophages adhesion rate on Ti-6Al-4V substrates: polishing and DLC coating effects

Abstract Introduction Various works have shown that diamond-like carbon (DLC) coatings are able to improve the cells adhesion on prosthesis material and also cause protection against the physical wear. On the other hand there are reports about the effect of substrate polishing, in evidence of that roughness can enhance cell adhesion. In order to compare and quantify the joint effects of both factors, i.e, polishing and DLC coating, a commonly prosthesis material, the Ti-6Al-4V alloy, was used as raw material for substrates in our studies of macrophage cell adhesion rate on rough and polished samples, coated and uncoated with DLC. Methods The films were produced by PECVD technique on Ti-6Al-4V substrates and characterized by optical profilometry, scanning electron microscopy and Raman spectroscopy. The amount of cells was measured by particle analysis in IMAGE J software. Cytotoxicity tests were also carried out to infer the biocompatibility of the samples. Results The results showed that higher the surface roughness of the alloy, higher are the cells fixing on the samples surface, moreover group of samples with DLC favored the cell adhesion more than their respective uncoated groups. The cytotoxity tests confirmed that all samples were biocompatible independently of being polished or coated with DLC. Conclusion From the observed results, it was found that the rougher substrate coated with DLC showed a higher cell adhesion than the polished samples, either coated or uncoated with the film. It is concluded that the roughness of the Ti-6Al-4V alloy and the DLC coating act complementary to enhance cell adhesion