- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
[IEEE 2018 IEEE 2nd International Conference on Dielectrics (ICD) - Budapest (2018.7.1-2018.7.5)] 2018 IEEE 2nd International Conference on Dielectrics (ICD) - An original in-situ way to build field grading materials (FGM) with permittivity gradient using electrophoresis
摘要： This paper reports on an original method developed at LAPLACE to structure field grading materials (FGM) by local handling of high permittivity ceramic (SrTiO3) particles in an epoxy resin using electrophoresis (i.e. DC voltage application). This new way of structuring composites allows building FGM with a high permittivity region (region with high particle concentration) while the rest of the composite remains with low particle concentration). The resin curing enables to ‘freeze’ the particles with this spatial arrangement. Process details and dielectric characterization of each region of the FGM composites are reported. Finally, a clear demonstration of the FGM performances, used as a field grading encapsulation material for high voltage power electronics modules, is shown supported both by field repartition simulation and experimental breakdown voltage improvements of encapsulated direct bonded copper (DBC) substrates.
关键词： SrTiO3,Encapsulation,Epoxy,Permittivity,Composites,Power modules,Field grading,FGM,Power electronics,Functionally graded materials,Electrophoresis
更新于2025-09-04 15:30:14
-
EuO epitaxy by oxygen scavenging on SrTiO <sub/>3</sub> (001): Effect of SrTiO <sub/>3</sub> thickness and temperature
摘要： The EuO/SrTiO3 heterojunction is a promising combination of a ferromagnetic material and a two-dimensional electron system. We explore the deposition of Eu metal on SrTiO3/Si pseudo-substrates, with varying SrTiO3 (STO) thickness, under ultrahigh vacuum conditions. By varying the thickness of the STO layer (2-10 nm) and the deposition temperature (20-300 °C), we investigate the process by which oxygen is scavenged from STO by Eu. In situ x-ray photoelectron spectroscopy is used to investigate the electronic structure of the nominal Eu/STO/Si stack. We ?nd that as a result of Eu deposition, epitaxial EuO is formed on thick STO (6-10 nm), leaving behind a highly oxygen-de?cient SrTiO3-δ layer of ～4 nm in thickness. However, if the thickness of the STO layer is comparable to or less than the scavenging depth, the crystal structure of STO is disrupted and a solid state reaction between Eu, Si, and STO occurs when the deposition is done at a high temperature (300 °C). On the other hand, at a low temperature (20 °C), only a 1-2 nm-thick EuO interlayer is grown, on top of which the Eu metal appears to be stable. This study elucidates the growth process under different conditions and provides a better understanding and control of this system.
关键词： SrTiO3,epitaxy,EuO,two-dimensional electron system,oxygen scavenging,ferromagnetic material
更新于2025-09-04 15:30:14