Perovskite lead-free dielectrics for energy storage applications

J. Y. Tsao,* S. Chowdhury, M. A. Hollis,* D. Jena, N. M. Johnson, K. A. Jones, R. J. Kaplar,* S. Rajan, C. G. Van de Walle, E. Bellotti, C. L. Chua, R. Collazo, M. E. Coltrin, J. A. Cooper, K. R. Evans, S. Graham, T. A. Grotjohn, E. R. Heller, M. Higashiwaki, M. S. Islam, P. W. Juodawlkis, M. A. Khan, A. D. Koehler, J. H. Leach, U. K. Mishra, R. J. Nemanich, R. C. N. Pilawa-Podgurski, J. B. Shealy, Z. Sitar, M. J. Tadjer, A. F. Witulski, M. Wraback, and J. A. Simmons

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Ultrawide-Bandgap Semiconductors: Research Opportunities and Challenges

Materials exhibiting high energy/power density are currently needed to meet the growing demand of portable electronics, electric vehicles and large-scale energy storage devices. The highest energy densities are achieved for fuel cells, batteries, and supercapacitors, but conventional dielectric capacitors are receiving increased attention for pulsed power applications due to their high power density and their fast charge-discharge speed. The key to high energy density in dielectric capacitors is a large maximum but small remanent (zero in the case of linear dielectrics) polarization and a high electric breakdown strength. Polymer dielectric capacitors offer high power/energy density for applications at room temperature, but above 100 °C they are unreliable and suffer from dielectric breakdown. For high-temperature applications, therefore, dielectric ceramics are the only feasible alternative. Lead-based ceramics such as La-doped lead zirconate titanate exhibit good energy storage properties, but their toxicity raises concern over their use in consumer applications, where capacitors are exclusively lead free. Lead-free compositions with superior power density are thus required. In this paper, we introduce the fundamental principles of energy storage in dielectrics. We discuss key factors to improve energy storage properties such as the control of local structure, phase assemblage, dielectric layer thickness, microstructure, conductivity, and electrical homogeneity through the choice of base systems, dopants, and alloying additions, followed by a comprehensive review of the state-of-the-art. Finally, we comment on the future requirements for new materials in high power/energy density capacitor applications.

Electroceramics for High-Energy Density Capacitors: Current Status and Future Perspectives

A nanoscale silver paste containing 30-nm silver particles that can be sintered at 280degC was made for interconnecting semiconductor devices. Sintering of the paste produced a microstructure containing micrometer-size porosity and a relative density of around 80%. Electrical and thermal conductivities of around 2.6times105 (Omegamiddotcm)-1 and 2.4W/K-cm, respectively, were obtained, which are much higher than those of the solder alloys that are currently used for die attachment and/or flip-chip interconnection of power semiconductor devices. The sintered porous silver had an apparent elastic modulus of about 9GPa, which is substantially lower than that of bulk silver, as well as most solder materials. The lower elastic modulus of the porous silver may be beneficial in achieving a more reliable joint between the device and substrate because of increased compliance that can better accommodate stress arising from thermal expansion mismatch

Low-Temperature Sintered Nanoscale Silver as a Novel Semiconductor Device-Metallized Substrate Interconnect Material

The physical and chemical properties of wide bandgap semiconductors silicon carbide and diamond make these materials an ideal choice for device fabrication for applications in many different areas, e.g. light emitters, high temperature and high power electronics, high power microwave devices, micro-electromechanical system (MEMS) technology, and substrates. These semiconductors have been recognized for several decades as being suitable for these applications, but until recently the low material quality has not allowed the fabrication of high quality devices. Silicon carbide and diamond based electronics are at different stages of their development. An overview of the status of silicon carbide's and diamond's application for high temperature electronics is presented.

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Silicon carbide and diamond for high temperature device applications

The fact that wide bandgap semiconductors are capable of electronic functionality at much higher temperatures than silicon has partially fueled their development, particularly in the case of SiC. It appears unlikely that wide bandgap semiconductor devices will find much use in low-power transistor applications until the ambient temperature exceeds approximately 300/spl deg/C, as commercially available silicon and silicon-on-insulator technologies are already satisfying requirements for digital and analog VLSI in this temperature range. However practical operation of silicon power devices at ambient temperatures above 200/spl deg/C appears problematic, as self-heating at higher power levels results in high internal junction temperatures and leakages. Thus, most electronic subsystems that simultaneously require high-temperature and high-power operation will necessarily be realized using wide bandgap devices, once they become widely available. Technological challenges impeding the realization of beneficial wide bandgap high ambient temperature electronics, including material growth, contacts, and packaging, are briefly discussed.

High-temperature electronics - a role for wide bandgap semiconductors?

The fabrication and testing of the first semiconductor transistors and small-scale integrated circuits (ICs) to achieve up to 3000 h of stable electrical operation at 500degC in air ambient is reported. These devices are based on an epitaxial 6H-SiC junction field-effect transistor process that successfully integrated high-temperature ohmic contacts, dielectric passivation, and ceramic packaging. Important device and circuit parameters exhibited less than 10% of change over the course of the 500degC operational testing. These results establish a new technology foundation for realizing durable 500degC ICs for combustion-engine sensing and control, deep-well drilling, and other harsh-environment applications.

/pdf/stable-electrical-operation-of-6h-sic-jfets-and-ics-for-2dxmgflmub.pdf

Stable Electrical Operation of 6H–SiC JFETs and ICs for Thousands of Hours at 500 $^{\circ}\hbox{C}$

https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1029/2017EA000355

Chemical Analysis of Materials Exposed to Venus Temperature and Surface Atmosphere

Testing of semiconductor electronics at temperatures above their designed operating envelope is recognized as vital to qualification and lifetime prediction of circuits. This work describes the high temperature electrical testing of prototype 4H silicon carbide (SiC) junction field effect transistor (JFET) integrated circuits (ICs) technology implemented with multilayer interconnects; these ICs are intended for prolonged operation at temperatures up to 773K (500 C). A 50 mm diameter sapphire wafer was used in place of the standard NASA packaging for this experiment. Testing was carried out between 300K (27 C) and 1150K (877 C) with successful electrical operation of all devices observed up to 1000K (727 C).

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4H-SiC JFET Multilayer Integrated Circuit Technologies Tested Up to 1000 K

Chemical sensor technology is being developed for leak detection, emission monitoring, and fire safety applications. The development of these sensors is based on progress in two types of technology: 1) micromachining and microfabrication (MEMS-based) technology to fabricate miniaturized sensors; 2) the development of high temperature semiconductors, especially silicon carbide. Using these technologies, sensors to measure hydrogen, hydrocarbons, nitrogen oxides, carbon monoxide, oxygen, and carbon dioxide are being developed. A description is given of each sensor type and its present stage of development. It is concluded that microfabricated sensor technology has significant potential for use in a range of aerospace applications.

/pdf/microfabricated-chemical-sensors-for-safety-and-emission-2907nt1brm.pdf

P. G. Neudeck

Papers

High-temperature electronics - a role for wide bandgap semiconductors?

Stable Electrical Operation of 6H–SiC JFETs and ICs for Thousands of Hours at 500 $^{\circ}\hbox{C}$

Chemical Analysis of Materials Exposed to Venus Temperature and Surface Atmosphere

4H-SiC JFET Multilayer Integrated Circuit Technologies Tested Up to 1000 K

Microfabricated chemical sensors for safety and emission control applications