Properties and Application of Geopolymers Vol. 841 (/MSF.841 /book) Development and Investigation of Materials Using Modern Techniques Vol. 840 (/MSF.840/book) Superplasticity in Advanced Materials ICSAM 2015 Vols. 838-839 (/MSF.838-839/book) 12th International Conference on High Speed Machining Vols. 836-837 (/MSF.836-837/book) Sintering Fundamentals II Vol. 835 (/MSF.835/book) Advanced Machining Technologies: Traditions and Innovations Vol. 834 (/MSF.834/book) Applied Materials and Technologies Vol. 833 (/MSF.833/book) Emerging Functional Materials: Book (/MSF.841/book) Papers (/MSF.841)

Materials Science Forum

Mechanical properties of nano-silver joints as die attach materials

The microbial fuel cell (MFC) technology offers sustainable solutions for distributed power systems and energy positive wastewater treatment, but the generation of practically usable power from MFCs remains a major challenge for system scale up and application. Commonly used external resistors will not harvest any usable energy, so energy-harvesting circuits are needed for real world applications. This review summarizes, explains, and discusses the different energy harvesting methods, components, and systems that can extract and condition the MFC energy for direct utilization. This study aims to assist environmental scientists and engineers to gain fundamental understandings of these electronic systems and algorithms, and it also offers research directions and insights on how to overcome the barriers, so the technology can be further advanced and applied in larger scale.

Practical Energy Harvesting for Microbial Fuel Cells: A Review

In order to take the full advantage of the high-temperature SiC and GaN operating devices, package materials able to withstand high-temperature storage and large thermal cycles have been investigated. The temperature under consideration here are higher than 200 °C. Such temperatures are required for several potential applications such as down-hole oil and gas industry for well logging, aircrafts, automotive, and space exploration. This review focuses on the reliability of a selection of potential components or materials used in the package assembly as the substrates, the die attaches, the interconnections, and the encapsulation materials. It reveals that, substrates with low coefficient of thermal expansion (CTE) conductors or with higher fracture resistant ceramics are potential candidates for high temperatures. Die attaches and interconnections reliable solutions are also available with the use of compatible metallization schemes. At this level, the reliability can also be improved by reducing the CTE mismatch between assembled materials. The encapsulation remains the most limiting packaging component since hard materials present thermomechanical reliability issues, while soft materials have low degradation temperatures. The review allows identifying reliable components and materials for high-temperature wide bandgap semiconductors and is expected to be very useful for researchers working for the development on high-temperature electronics.

Survey of High-Temperature Reliability of Power Electronics Packaging Components

Silver (Ag) has been under development for use as interconnect material for power electronics packaging since the late 1980s. Despite its long development history, high thermal and electrical conductivities, and lead-free composition, sintered Ag technology has limited market penetration. This review sets out to explore what is required to make this technology more viable. This review also covers the origin of sintered Ag, the different types and application methods of sintered Ag pastes and laminates, and the long-term reliability of sintered Ag joints. Sintered Ag pastes are classified according to whether pressure is required for sintering and further classified according to their filler sizes. This review discusses the main methods of applying Ag pastes/laminates as die-attach materials and the related processing conditions. The long-term reliability of sintered Ag joints depends on the density of the sintered joint, selection of metallization or plating schemes, types of substrates, substrate roughness, formulation of Ag pastes/laminates, joint configurations (i.e., joint thicknesses and die sizes), and testing conditions. This paper identifies four challenges that must be overcome for the proliferation of sintered Ag technology: changes in materials formulation, the successful navigation of the complex patent landscape, the availability of production and inspection equipment, and the health concerns of Ag nanoparticles. This paper is expected to be useful to materials suppliers and semiconductor companies that are considering this technology for their future packages.

/pdf/are-sintered-silver-joints-ready-for-use-as-interconnect-2rnz0z0bm7.pdf

Are Sintered Silver Joints Ready for Use as Interconnect Material in Microelectronic Packaging

This work reports on the fabrication and electrical characterization of 3 different diodes. The first one is a Schottky diode with a single 50 mm P+ ring between the edge termination and the active area. The two other diodes are JBS with a 3 mm P+ strips separated by 4 mm and 8 mm respectively. The breakdown voltage ranges from 2.7kV up to 3.7kV depending on the P+/N area. The 3 different diodes exhibit a similar on-resistance versus the temperature behavior. Moreover, no contribution of the bipolar conduction is observed and no degradation has been observed when a forward stress is performed in forward mode and also in reverse.

/pdf/impact-of-design-on-electrical-characteristics-of-3-5-kv-4h-4vzuq6sx8r.pdf

Impact of Design on Electrical Characteristics of 3.5 kV 4H-SiC JBS Diode

The paper presents the design and measurements for very high frequency, low power, inductive DC-DC converters (100 MHz, 3:3 V input voltage, 350 mW output power). Preliminary analyses including the state-of-the-art, the architecture and the technology are briefly discussed. A converter is designed as a power system-in-package, based on a cascode power stage in a 2.5D assembly using a capacitive interposer embedding deep trench capacitors. Experimental characterizations are presented. An efficiency of 90 % is demonstrated while converting from 3:3 V to 2:4 V and supplying 150 mA, showing a + 8 % efficiency improvement compared to a converter with a standard power stage.

Design of a highly integrated, high frequency, low power DC-DC converter with cascode power stage with a 2.5D approach

Two sample SiC JFET are characterized and used to build a high operating temperature converter. Power losses are evaluated, the effect of temperature on ONState resistance and saturation current is measured and discussed. Temperature effects on dynamic behaviour is not a major issue. Total losses vary with temperature. A 600V/300V converter is build and tested. JFET and inductor are cooled at 300deg C.

https://hal.archives-ouvertes.fr/hal-00413394/document

High temperature operating converter

The expansion of the electrical communications and distribution networks strongly contribute to the increase in the risks of appearance of defaults, such as over-voltage and/or over-current These developments promote the emergence of safety devices for serial protection commonly named Current Limiting Devices (CLD's) This work presents the design, manufacture and characterization of silicon carbide accuMOSFET of high power density ratings Components able to limit the current Lip to 450A @ 350V were manufactured and characterized Specific characterization test benches were developed, able to provide high energy Pulses required for characterization CLDs behavior subjected to short overloads has been measured experimentally and analyzed be means of simulations for long-time overloads A maximum sustainable high energy of 35 Joules has been estimated This achievement give opportunities to build new architectures of serial protection systems

High Power Density SiC 450A AccuMOSFET for Current Limiting Applications

Harvesting of ambient radio-frequency energy is largely covered in the literature. The RF energy harvester is considered most of the time as a standalone board. There is an interest to add the RF harvesting function on an already-designed object. Polymer objects are considered here, manufactured through an additive process and the paper focuses on the rapid prototyping of the harvester using a plastronic approach. An array of four antennas is considered for circular polarization with high self-isolation. The RF circuit is obtained using an electroless copper metallization of the surface of a 3D substrate fabricated using stereolithography printing. The RF properties of the polymer resin are not optimal; thus, the interest of this work is to investigate the potential capabilities of such an implementation, particularly in terms of freedom of 3D design and ease of fabrication. The electromagnetic properties of the substrate are characterized over a band of 0.5–2.5 GHz applying the two-transmission-line method. A circular polarization antenna is experimented as a rapid prototyping vehicle and yields a gain of 1.26 dB. A lab-scale prototype of the rectifier and power management unit are experimented with discrete components. The cold start-up circuit accepts a minimum voltage of 180 mV. The main DC/DC converter operates under 1.4 V but is able to compensate losses for an input DC voltage as low as 100 mV (10 μW). The rectifier alone is capable of 3.5% efficiency at −30 dBm input RF power. The global system of circularly polarized antenna, rectifier, and voltage conversion features a global experimental efficiency of 14.7% at an input power of −13.5 dBm. The possible application of such results is discussed.

/pdf/radio-frequency-energy-harvesting-using-rapid-3d-plastronics-3up9nu2s.pdf

Pascal Bevilacqua

Papers

Impact of Design on Electrical Characteristics of 3.5 kV 4H-SiC JBS Diode

Design of a highly integrated, high frequency, low power DC-DC converter with cascode power stage with a 2.5D approach

High temperature operating converter

High Power Density SiC 450A AccuMOSFET for Current Limiting Applications

Radio-Frequency Energy Harvesting Using Rapid 3D Plastronics Protoyping Approach: A Case Study