1/31/2024 0 Comments Ion bonding glassFigure 1(a) shows thermogravimetric analysis-differential thermal analysis (TGA-DTA) results of the Ag 2O paste with increasing temperature. In addition, it is also necessary to limit the preheating temperature below the reduction temperature to avoid promoting this reaction, as the initial formation of excess amounts of AgNPs during the preheating process could result in their cohesion and inhibition of sintering. To utilize the decomposition reaction of a paste comprising Ag 2O and diethylene glycol (C 4H 10O 3), control of the preheating before the bonding is useful in order to remove excess solvent, which is likely to hinder the sintering of particles. Finally, the adhesion behaviour of the AgNP on the SiO 2 substrate was modelled and compared to the experimental results.Įvaluation of the bond quality of silicon-based materials Then, the influence of the bonding temperature on the joint strength was evaluated in addition to interfacial microstructural observations. For the bonding of Si-materials, a thermal process was firstly designed based on the investigation of the decomposition behaviour of a paste comprising Ag 2O and organic solvent using thermal analysis. Here, we report the direct bonding of Si-materials, such as Si, SiO 2, and SiC, by Ag sintering derived from the two different decomposition reactions of Ag 2O. We hypothesized that the decomposition of Ag 2O could be used in the bonding of Ag to various Si-materials by taking advantage of the good adhesion between the intermediate forms of Ag and the silicon oxide. SiO x) layer is generally formed on the surface of Si-materials as a native oxide film. The diffusion of Ag ions into SiO2 without such an external driving force has not be studied in detail to our knowledge, but the formation of metallic ions would be likely to contribute to the bonding of SiO 2 with metals.ĭuring the reaction between Ag 2O and an organic solvent, AgNPs can be produced by two different processes a redox reaction temporarily producing Ag ions, and thermal decomposition during heating 26, 27, 28, which can induce the formation of Ag ions or atoms as an intermediate state. It was also shown that the diffusion of metallic ions into SiO 2 is facilitated under an electric field 24, 25. The attraction of Ag ions to the SiO 2 surface is enhanced after surface chemical treatments 20, 21, such as amination or the rupture of Si–O–Si bonds by ultrasonic radiation 22 or electron irradiation 23. soda-lime glass, into which Ag diffuses easily due to the ion exchange reaction 18, 19. The adhesion and diffusion of Ag into pure SiO 2 is often difficult 17, unlike some glasses containing sodium or potassium, e.g. Many studies have been conducted on the diffusivity of Ag into SiO 2 and the adhesion between these materials 17, 18, 19, 20, 21, 22, 23. However, very little is known about the bonding morphology between the Ag and Si-materials as they have the high covalent properties, which requires surface pre-treatments even when using the AgNP joining process 4, 16. Thus, an application of the bonding method to ceramics with high ion-binding properties was proposed. In particular, a typical bonding mechanism of Ag to Al 2O 3 was suggested Ag ions temporarily generated during the redox reaction attach to the Al 2O 3 surface, leading to the formation of an initial Ag layer that facilitates the sintering of the AgNPs. Al 2O 3), can be bonded using this method 15. Recent studies reported that, not only metals 12, 13, 14, but some aluminium oxide ceramics (e.g. Nanoparticles smaller than 10 nm show an apparent melting-point depression 8, 9, 10 caused by the high surface to volume ratio 11, making them more reactive. Hence, conventional metal-to-ceramic bonding involves indirect processes.Ī bonding method involving the sintering of Ag derived from the redox reaction between Ag 2O and an organic solvent has been reported 6, 7: Ag nanoparticles (AgNPs) are generated during the bonding process as a result of the redox reaction. For example, titanium or nickel have been deposited on Si 2, 3 and SiC 4, 5 substrates. metallization, are necessary to facilitate bonding between metal and semiconductors (or various ceramics) 2, 3, 4, 5. Since covalent and ionic bonds are generally the principal types of chemical bonds in these semiconductors, compatibility with the metallic bonds is greatly limited. The bonding between metal and silicon-based materials (Si-material), such as silicon carbide (SiC), a wide-bandgap semiconductor, and silicon dioxide (SiO 2), used as gate oxide in metal-oxide-semiconductor (MOS) structures, has attracted growing interest in the recent development of the power electronics field 1.
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