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Silicon nitride

About: Silicon nitride is a research topic. Over the lifetime, 32678 publications have been published within this topic receiving 413599 citations. The topic is also known as: N₄Si₃.


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Journal ArticleDOI
01 Aug 1998
TL;DR: Surface micromachining is characterized by the fabrication of micromechanical structures from deposited thin films as discussed by the authors, which typically requires that they be freed from the planar substrate.
Abstract: Surface micromachining is characterized by the fabrication of micromechanical structures from deposited thin films. Originally employed for integrated circuits, films composed of materials such as low-pressure chemical-vapor-deposition polycrystalline silicon, silicon nitride, and silicon dioxides can be sequentially deposited and selectively removed to build or "machine" three-dimensional structures whose functionality typically requires that they be freed from the planar substrate. Although the process to accomplish this fabrication dates from the 1960's, its rapid extension over the past few years and its application to batch fabrication of micromechanisms and of monolithic microelectromechanical systems (MEMS) make a thorough review of surface micromachining appropriate at this time. Four central issues of consequence to the MEMS technologist are: (i) the understanding and control of the material properties of microstructural films, such as polycrystalline silicon, (ii) the release of the microstructure, for example, by wet etching silicon dioxide sacrificial films, followed by its drying and surface passivation, (iii) the constraints defined by the combination of micromachining and integrated-circuit technologies when fabricating monolithic sensor devices, and (iv) the methods, materials, and practices used when packaging the completed device. Last, recent developments of hinged structures for postrelease assembly, high-aspect-ratio fabrication of molded parts from deposited thin films, and the advent of deep anisotropic silicon etching hold promise to extend markedly the capabilities of surface-micromachining technologies.

663 citations

Journal ArticleDOI
01 Jan 1996-Nature
TL;DR: In this paper, a boron-containing silicon nitride/carbide ceramic that does not degrade at temperatures up to 2,000 °C even in nitrogen-free environments is presented.
Abstract: CERAMICS based on silicon nitride and carbide are strong and stable at high temperatures, and are therefore under investigation for the fabrication of motor and turbine parts1–3. But silicon nitride decomposes at about 1,400 °C in vacuum and 1,775 °C in 0.1 MPa nitrogen4,5, limiting the high-temperature range of its technological uses. Here we describe a boron-containing silicon nitride/carbide ceramic that does not degrade at temperatures up to 2,000 °C even in nitrogen-free environments. We synthesize the material in a polymer-to-ceramic transformation6 from a single polymeric polyborosilazane precursor. On heating at 1,000 °C in argon we obtain a ceramic with the composition Si3.0B1.0C4.3N2.0. The ceramic begins to convert to a polycrystalline composite of silicon nitride and carbide (with some non-crystalline boron nitride) at 1,700 °C, a process that is completed (without substantial change in elemental composition) at 2,000 °C.

634 citations

Journal ArticleDOI
TL;DR: These analyses identified the MEMS component materials, gold, silicon nitride, silicon dioxide, SU-8(TM), and silicon as biocompatible, with gold and silicon showing reduced biofouling.

596 citations

Journal ArticleDOI
TL;DR: In this paper, the authors explore how dielectric polymer composites with high thermal conductivity have been developed and explore how fillers can be used to increase the thermal conductivities of a polymer.
Abstract: The continuing miniaturization of electronic devices and the increasing power output of electrical equipment have created new challenges in packaging and insulating materials. The key goals are to develop materials with high thermal conductivity, low coefficient of thermal expansion (CTE), low dielectric con stant, high electrical resistivity, high breakdown strength, and most importantly, low cost. Polymeric materials have attracted increasing interest because of their excellent processability and low cost; however, most polymers are thermally insulating and have a thermal conductivity between 0.1 and 0.5 W-m-ι-K"1. One approach to increase the thermal conductivity of a polymer is to introduce high-thermal-conductivity fillers, such as aluminum oxide, aluminum nitride, boron nitride, silicon nitride, beryllium oxide, or diamond. In this review paper, we explore how dielectric polymer composites with high thermal conductivity have been developed.

581 citations

Journal ArticleDOI
31 Mar 2011-ACS Nano
TL;DR: Novel toughening mechanisms were observed that show GPL wrapping and anchoring themselves around individual ceramic grains to resist sheet pullout and the resulting cage-like graphene structures that encapsulate the individual grains were observed to deflect propagating cracks in not just two but three dimensions.
Abstract: The majority of work in graphene nanocomposites has focused on polymer matrices. Here we report for the first time the use of graphene to enhance the toughness of bulk silicon nitride ceramics. Ceramics are ideally suited for high-temperature applications but suffer from poor toughness. Our approach uses graphene platelets (GPL) that are homogeneously dispersed with silicon nitride particles and densified, at ∼1650 °C, using spark plasma sintering. The sintering parameters are selected to enable the GPL to survive the harsh processing environment, as confirmed by Raman spectroscopy. We find that the ceramic's fracture toughness increases by up to ∼235% (from ∼2.8 to ∼6.6 MPa·m(1/2)) at ∼1.5% GPL volume fraction. Most interestingly, novel toughening mechanisms were observed that show GPL wrapping and anchoring themselves around individual ceramic grains to resist sheet pullout. The resulting cage-like graphene structures that encapsulate the individual grains were observed to deflect propagating cracks in not just two but three dimensions.

575 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
2023245
2022529
2021421
2020686
2019994
2018911