Review on thermal energy storage with phase change: materials, heat transfer analysis and applications

Light-Emitting Diodes. (Monographs in Electrical and Electronic Engineering.) By A. A. Bergh and P. J. Dean. Pp. viii+591. (Clarendon: Oxford; Oxford University: London, 1976.) £22.

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Light-emitting diodes

Gallium oxide (Ga2O3) is emerging as a viable candidate for certain classes of power electronics, solar blind UV photodetectors, solar cells, and sensors with capabilities beyond existing technologies due to its large bandgap. It is usually reported that there are five different polymorphs of Ga2O3, namely, the monoclinic (β-Ga2O3), rhombohedral (α), defective spinel (γ), cubic (δ), or orthorhombic (e) structures. Of these, the β-polymorph is the stable form under normal conditions and has been the most widely studied and utilized. Since melt growth techniques can be used to grow bulk crystals of β-GaO3, the cost of producing larger area, uniform substrates is potentially lower compared to the vapor growth techniques used to manufacture bulk crystals of GaN and SiC. The performance of technologically important high voltage rectifiers and enhancement-mode Metal-Oxide Field Effect Transistors benefit from the larger critical electric field of β-Ga2O3 relative to either SiC or GaN. However, the absence of clear demonstrations of p-type doping in Ga2O3, which may be a fundamental issue resulting from the band structure, makes it very difficult to simultaneously achieve low turn-on voltages and ultra-high breakdown. The purpose of this review is to summarize recent advances in the growth, processing, and device performance of the most widely studied polymorph, β-Ga2O3. The role of defects and impurities on the transport and optical properties of bulk, epitaxial, and nanostructures material, the difficulty in p-type doping, and the development of processing techniques like etching, contact formation, dielectrics for gate formation, and passivation are discussed. Areas where continued development is needed to fully exploit the properties of Ga2O3 are identified.

A review of Ga2O3 materials, processing, and devices

International Technology Roadmap for Semiconductors 2003の要求清浄度について － シリコンウエハ表面と雰囲気環境に要求される清浄度, 分析方法の現状について －

Small, light weight and multifunctional electronic components are attracting much attention because of the rapid growth of the wireless communication systems and microwave products in the consumer electronic market. The component manufacturers are thus forced to search for new advanced integration, packaging and interconnection technologies. One solution is the low temperature cofired ceramic (LTCC) technology enabling fabrication of three-dimensional ceramic modules with low dielectric loss and embedded silver electrodes. During the past 15 years, a large number of new dielectric LTCCs for high frequency applications have been developed. About 1000 papers were published and ∼500 patents were filed in the area of LTCC and related technologies. However, the data of these several very useful materials are scattered. The main purpose of this review is to bring the data and science of these materials together, which will be of immense help to researchers and technologists all over the world. The comme...

Low loss dielectric materials for LTCC applications: a review

Heat transfer: a review of 1999 literature.

Heat transfer: a review of 2002 literature

Cooling Electronic Equipment

A novel ldquoshunt attachrdquo configuration for chip-scale thermoelectric (TE) generation of electric power from microprocessor waste heat is described, modeled, and parametrically analyzed. The generated electricity is used to drive a cooling fan that convectively cools the chip. A prototype using heat-driven cooling through off-the-shelf TE modules and a low-voltage fan was built and successfully applied to the thermal management of a high-power mobile processor in a portable equipment form factor.

Heat driven cooling of portable electronics using thermoelectric technology

As hotspots become an increasingly important factor in the design of electronic devices, it has become essential to develop novel near-junction cooling methods. Steady-state thermoelectric cooling has previously been considered for the removal of localized hotspots on various substrates. In this paper, the transient behavior of a germanium thermoelectric self-cooler, in which the chip substrate is used as a leg of the thermoelectric circuit, is described. A 3-D thermoelectric numerical model was created in the commercial FEA package ANSYS and is used to explore the effects of various initial conditions, current pulse durations, current pulse magnitudes, pulse shapes, and die thicknesses. The results suggest that pulsed transient thermoelectric cooling has the potential to improve hotspot temperature reduction by approximately 30% relative to what is achievable in steady state. In addition, it was found that larger currents generally cause more rapid thermoelectric cooling, but also result in large overshoot temperatures and that the applied current profile has a strong effect on the transient behavior of the cooler.

Avram Bar-Cohen

Papers

Heat transfer: a review of 1999 literature.

Heat transfer: a review of 2002 literature

Cooling Electronic Equipment

Heat driven cooling of portable electronics using thermoelectric technology

Pulsed Thermoelectric Cooling for Improved Suppression of a Germanium Hotspot