Castable particulate-filled epoxy resins exhibiting excellent thermal conductivity have been prepared using hexagonal boron nitride (hBN) and cubic boron nitride (cBN) as fillers. The thermal conductivity of boron nitride filled epoxy matrix composites was enhanced up to 217% through silane surface treatment of fillers and multi-modal particle size mixing (two different hBN particle sizes and one cBN particle size) prior to fabricating the composite. The measurements and interpretation of the curing kinetics of anhydride cured epoxies as continuous matrix, loaded with BN having multi-modal particle size distribution, as heat conductive fillers, are highlighted. This study evidences the importance of surface engineering and multi-modal mixing distribution applied in inorganic fillered epoxy-matrix composite.

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To develop new composites with sufficiently high thermal conductivity and suitably controlled D k value for PCBs application, the composites were prepared from epoxy and AlN or BN fillers, and the effects of content, size, size distribution, and morphology of two fillers on the thermal and dielectric properties of the composites were investigated. The results showed that either AlN or BN fillers can greatly increase T g and thermal conductivity, decreasing CTE and D f , and suitably controlling the increase of D k . At the same filler content, BN-filled composites exhibit better thermal performance and dielectric properties compared to AlN-filled composites. In the case of BN-filled composites, it is found that plateletshaped micro-BN filled composite has lower T g and higher CTE compared with particle-shaped nano-BN filled composite, but its thermal conductivity is remarkably higher than that of nano-BN filled composite. When hybrid BN fillers are used, thermal conductivity further increases. For micro-or nano-BN filled composite, the composite shows decreased T g and increased D k at high fraction of BN, but hybrid BN-filled composite still has high T g and similar D k with epoxy even if at high fraction of BN. Compared with single-sized AlN-filled composite, it is found that hybrid-sized AlN-filled composite has higher T g and lower CTE, but has lower thermal conductivity. To predict thermal conductivity and D k in the investigated materials system, different models reported in the literature were analyzed and compared with the experimental data. Finally, suitable models were recommended.

The speed of silicon-based transistors has reached an impasse in the recent decade, primarily due to scaling techniques and the short-channel effect. Conversely, graphene (a revolutionary new material possessing an atomic thickness) has been shown to exhibit a promising value for electrical conductivity. Graphene would thus appear to alleviate some of the drawbacks associated with silicon-based transistors. It is for this reason why such a material is considered one of the most prominent candidates to replace silicon within nano-scale transistors. The major crux here, is that graphene is intrinsically gapless, and yet, transistors require a band-gap pertaining to a well-defined ON/OFF logical state. Therefore, exactly as to how one would create this band-gap in graphene allotropes is an intensive area of growing research. Existing methods include nano-ribbons, bilayer and multi-layer structures, carbon nanotubes, as well as the usage of the graphene substrates.Graphene transistors can generally be classified according to two working principles. The first is that a single graphene layer, nanoribbon or carbon nanotube can act as a transistor channel, with current being transported along the horizontal axis. The second mechanism is regarded as tunneling, whether this be band-to-band on a single graphene layer, or vertically between adjacent graphene layers. The high-frequency graphene amplifier is another talking point in recent research, since it does not require a clear ON/OFF state, as with logical electronics. This paper reviews both the physical properties and manufacturing methodologies of graphene, as well as graphene-based electronic devices, transistors, and high-frequency amplifiers from past to present studies. Finally, we provide possible perspectives with regards to future developments.Not long before graphene was first manufactured by the Manchester research group in 2004 [1][2][3][4], theorists still believed that such two-dimensional structures were unstable due to thermal fluctuations [4,5], famously referred to as the Landau-Peierls arguments (cf. also ). Recently, the paradox behind graphene's existence has been resolved [5,6], and that it can be stabilised by transverse lattice distortions [8]. Stable forms of various other two-dimensional crystals such as graphene, silicene and germanene have all been attained [6,9]. Graphene was the first example which is able to exist in a single atomic layer with honeycomb hierarchy [1] (cf. Figure 1). It is composed of a single layer of carbon atoms, and can be extracted from graphite with full preservation of the hexagonal honeycomb structure (also referred to as chicken wire for quantum information processing [10]). This material has astonishing properties: it is stronger than diamond, more conductive than copper and more flexible than rubber. Graphene has primarily attracted the attention of scientific and engineering communities, due to its outstanding electrical, thermal and optical properties [11][12][13][14], displaying having a strong potential for m...

It is evident that embedded passive components (EPCs) allow packaging substrate miniaturization and have the potential to reduce costs. Moreover, they exhibit superior electrical behaviour with respect to the minimization of parasitic effects. However, as for most emerging technologies, there is no well-established process or method for EPCs that lead to the desired result, but many have been and are still being investigated. This article attempts to review the state of the art of resistor and capacitor EPCs, including an assessment of the pros and cons of the various technologies pursued.In the review, it is found that compared to discrete surface mount devices, EPCs provide (in order of current importance): space reduction of 30% or more, better HF signal integrity and potential cost reduction. Embedded resistors in thin-film technology are, in general, restricted to small resistance values up to a few kΩ. Embedded resistors in ceramic thick-film technology require a high temperature curing process and much care during lamination, but they can be combined with embedded capacitors and exhibit high stability. Whereas embedded resistors in polymer thickfilm technology require a low curing temperature and can be combined with capacitors, they exhibit poorer electrical properties and stability. Moreover, tolerances of embedded resistors after manufacturing are exceeded by 15%, independent of the manufacturing technology, which means that laser trimming is required.Embedded capacitors are based mostly on barium-titanite with a dielectric constant of only approximately 20, which limits the capacitance density to a few nF/in 2 . Ferroelectric material with a dielectric constant up to 2000 for embedded capacitors has been investigated but not yet established. Besides the traditional