Crystallization effect on the dielectric strength of fluorinated parylene at high temperature

2012 ◽  
Vol 15 (2-3) ◽  
pp. 157-168 ◽  
Author(s):  
Mireille Bechara ◽  
Rabih Khazaka ◽  
Sombel Diaham ◽  
Marie-Laure Locatelli ◽  
Pierre Bidan
Keyword(s):  
High Temperature ◽  
Dielectric Strength ◽  
Crystallization Effect

Characterization of Silicone Gel for High Temperature Encapsulation in High Voltage WBG Power Modules

2017 ◽  
Vol 2017 (1) ◽  
pp. 000312-000317
Author(s):  
Adam Morgan ◽  
Xin Zhao ◽  
Jason Rouse ◽  
Douglas Hopkins
Keyword(s):  
High Temperature ◽  
Thermal Aging ◽  
Dielectric Strength ◽  
Material Structure ◽  
Power Module ◽  
Leakage Currents ◽  
Test Vehicle ◽  
Silicone Gel ◽  
Power Modules ◽  
Silicone Gels

Abstract One of the most important advantages of wide-bandgap (WBG) devices is high operating temperature (>200°C). Power modules have been recognized as an enabling technology for many industries, such as automotive, deep-well drilling, and on-engine aircraft controls. These applications are all required to operate under some form of extreme environmental conditions. Silicone gels are the most popular solution for the encapsulation of power modules due to mechanical stress relief enabled by a low Young's modulus, electrical isolation achieved due to high dielectric strength, and a dense material structure that protects encapsulated devices against moisture, chemicals, contaminants, etc. Currently, investigations are focused on development of silicone gels with long-term high-temperature operational capability. The target is to elevate the temperature beyond 200°C to bolster adoption of power modules in the aforementioned applications. WACKER has developed silicone gels with ultra-high purity levels of < 2ppm of total residual ions combined with > 200°C thermal stability. In this work, leakage currents through a group of WACKER Chemie encapsulant silicone gels (A, B, C) are measured and compared for an array of test modules after exposure to a 12kV voltage sweep at room temperature up to 275°C, and thermal aging at 150°C for up to more than 700 hours. High temperature encapsulants capable of producing leakage currents less than 1μA, are deemed acceptable at the given applied blocking voltage and thermal aging soak temperature. To fully characterize the high temperature encapsulants, silicone gel A, B, and C, an entire high temperature module is used as a common test vehicle. The power module test vehicle includes: 12mil/40mil/12mil Direct Bonded Copper (DBC) substrates, gel under test (GUT), power and Kelvin connected measurement terminals, thermistor thermal sensor to sense real-time temperature, and 12mil Al bonding wires to manage localized high E-Fields around wires. It was ultimately observed that silicone gels B and C were capable of maintaining low leakage current capabilities under 12kV and 275°C conditions, and thus present themselves as strong candidates for high-temperature WBG device power modules and packaging.

New model of dielectric strength of Debye relaxation in monohydroxy alcohols

2019 ◽  
Vol 33 (26) ◽  
pp. 1950313
Author(s):  
Li-Na Wang ◽  
Xing-Yu Zhao ◽  
Yi-Neng Huang
Keyword(s):  
Experimental Data ◽  
Exact Solution ◽  
High Temperature ◽  
Ising Model ◽  
Dielectric Spectroscopy ◽  
Dielectric Strength ◽  
Experimental Results ◽  
Debye Relaxation ◽  
New Model ◽  
Model Predictions

The Debye relaxation of dielectric spectroscopy exists extensively in monohydroxy alcohols, and the existing theory of the dielectric strength is obviously inconsistent with the experimental results. In this paper, we propose an Ising model of infinite free-rotating pseudospin chains and get the exact solution of the dielectric strength versus temperature. The model predictions are qualitatively consistent with the experimental results, especially the crossover from the low to the high-temperature Curie–Weiss law. The quantitative comparisons indicate that the model predictions can agree well with the experimental data below 250 K.

The Study of High Temperature Annealing of a-SiC:H Films

2006 ◽  
Vol 514-516 ◽  
pp. 18-22
Author(s):  
Shibin Zhang ◽  
Z. Hu ◽  
Leandro Raniero ◽  
X. Liao ◽  
Isabel Ferreira ◽  
...  
Keyword(s):  
High Temperature ◽  
Chemical Vapor ◽  
Nitrogen Atmosphere ◽  
High Temperature Annealing ◽  
X Ray Diffraction ◽  
X Ray ◽  
Metal Induced Crystallization ◽  
Vapor Deposition Technique ◽  
Crystallization Effect ◽  
Induced Crystallization

A series of amorphous silicon carbide films were prepared by plasma enhanced chemical vapor deposition technique on (100) silicon wafers by using methane, silane, and hydrogen as reactive resources. A very thin (around 15 Å) gold film was evaporated on the half area of the a- SiC:H films to investigate the metal induced crystallization effect. Then the a-SiC:H films were annealed at 1100 0C for 1 hour in the nitrogen atmosphere. Fourier transform infrared spectroscopy (FTIR), X-Ray diffraction (XRD), and scanning electron microscopy (SEM) were employed to analyze the microstructure, composition and surface morphology of the films. The influences of the high temperature annealing on the microstructure of a-SiC:H film and the metal induced metallization were investigated.

Study on Improvement Effect of Aramid Fiber and PVA Fiber on of Mica Paper Strength and Dielectric Properties

2011 ◽  
Vol 214 ◽  
pp. 508-512 ◽  
Author(s):  
Zhao Qing Lu ◽  
Mei Yun Zhang ◽  
Li Hua ◽  
Guang Yun Zhu
Keyword(s):  
Tensile Strength ◽  
High Temperature ◽  
Dielectric Properties ◽  
Optimum Condition ◽  
Dielectric Strength ◽  
Aramid Fiber ◽  
Paper Strength ◽  
Improvement Effect ◽  
Pva Fiber ◽  
Insulation Performance

In order to improve the properties of mica paper, aramid fiber and PVA fiber were employed in mica paper as additive. Aramid fiber can act as skeleton and improve the dielectric strength of mica paper greatly accordingly at the optimum dosages of aramid fiber, 4%. When 3% of PVA fibers were added the tensile strength of mica paper increased significantly. It is because PVA fibers can smelt and act as bond for mica flake and aramid fiber under high temperature. The optimum beating degree of aramid fiber was 35 oSR, and the optimum drying temperature was 100°C. Compared with traditional mica paper, dielectric strength of composite mica paper with aramid fiber and PVA fiber increased above 25% and tensile strength increased 2.30 times under this optimum condition. In addition, the insulation performance of composite mica paper also improved substantially.

scholarly journals CHARACTERIZATION OF ELECTRICAL PORCELAIN INSULATORS FROM LOCAL CLAYS

2015 ◽  
Vol 3 (1) ◽  
pp. 26-36
Author(s):  
Okolo Chidiebere Cajetan ◽  
Ezechukwu O.A. ◽  
Olisakwe C.O. ◽  
Ezendokwelu C.E. ◽  
Umunna Chike
Keyword(s):  
High Temperature ◽  
Electrical Property ◽  
Dielectric Strength ◽  
Test Sample ◽  
Electrical Porcelain ◽  
Plastic Body ◽  
Clay Sample ◽  
Air Drying ◽  
Porcelain Insulators

In this thesis, the characterization of electrical porcelain insulators based on local clays has been investigated. Test samples were made by varying the quantities of feldspar and silica required to form a mouldable plastic body with each clay sample. The clay samples were bisque fired which is to 900°C and glazed before it was fired to 1250°C after air-drying. An electrical property such as dielectric strength (breakdown voltage) was determined for each test sample that survived the high temperature. The composition for optimum properties from Ekwulobia and Iva Valley clays each is at composition 3 of 60% clay, 25% feldspar and 15% silica; while for Nawfija clay, the composition for optimum properties was 50% clay, 30% feldspar and 20% silica. Porcelain insulators containing 50-70% clay, 20-30% feldspar and 10-20% silica were found to have requisite properties that make them suitable for domestic production of porcelains insulators from the clay samples studied.

Temperature Dependence of High Dielectric Strength Potting Materials for Medium Voltage Power Modules

2015 ◽  
Vol 12 (4) ◽  
pp. 212-218
Author(s):  
Chad B. O'Neal ◽  
Matthew Feurtado ◽  
Jennifer Stabach ◽  
Ty McNutt ◽  
Brandon Passmore
Keyword(s):  
High Temperature ◽  
Leakage Current ◽  
Dielectric Strength ◽  
Operating Voltage ◽  
Power Module ◽  
Dielectric Thickness ◽  
Medium Voltage ◽  
Current Test ◽  
Power Modules ◽  
High Dielectric

Voltage insulation inside power modules is paramount for functional and reliable operation. Dielectric potting materials are stressed as the overall size of these modules is reduced due to size, weight, and cost considerations while the operating voltage of these modules continue to increase. In particular, voltage ratings of silicon carbide (SiC) device technologies will continue to increase above 6.5 kV into the tens of kilovolts in the future. SiC devices are also often operated at higher junction temperatures to take advantage of the high-temperature capabilities of the material. As the module temperature increases, the dielectric strength of insulating materials in the module tends to decrease, which is a serious concern for a compact power module operating at many kilovolts. A plurality of high-temperature-rated, high dielectric strength potting materials was tested for voltage breakdown and leakage current up to 30 kV and 250°C. A range of different materials, both conventional and novel, were tested, including silicones and Parylene. Materials were selected with a dielectric strength >20 kV/mm, an operating temperature range of 200°C or higher, and low hardness and modulus of elasticity with the intent of demonstrating the capability of blocking 20 kV or more in a reasonable thickness. A custom test setup was constructed to apply the voltage to test samples while measuring the breakdown voltage and simultaneously recording the leakage current. Test coupons were designed to provide a range of dielectric thicknesses over which to test the dielectric strength. Although voltage isolation may increase with increased dielectric thickness, the volt per millimeter isolation rate often decreases. The performance degradation of these materials over temperature is plotted, and insulation thicknesses are suggested for use with medium voltages at operating temperatures above 175°C.

Optimizing the Thermally Oxidized 4H-SiC MOS Interface for P-Channel Devices

2007 ◽  
Vol 556-557 ◽  
pp. 667-670 ◽  
Author(s):  
Mrinal K. Das ◽  
Sarah K. Haney ◽  
Charlotte Jonas ◽  
Qing Chun Jon Zhang ◽  
Sei Hyung Ryu
Keyword(s):  
High Temperature ◽  
High Performance ◽  
Operating Temperature ◽  
Inversion Layer ◽  
High Mobility ◽  
Dielectric Strength ◽  
Temperature Measurements ◽  
Hole Conduction ◽  
Activation Annealing ◽  
Operating Temperature Range

Optimization of the thermally oxidized 4H-SiC MOS interface has produced p-channel lateral MOSFETs with hole inversion layer mobility as high as 10 cm2/Vs. This has been accomplished by identifying the 1200oC Dry, 950oC Wet (un-nitrided) oxidation as ideal for hole conduction across the MOS inversion layer and by implant activation annealing at 1800oC of the heavily implanted n-type well. High temperature measurements show that the high mobility and normally-off operation is maintained throughout the operating temperature range. Oxide leakage measurements yield a dielectric strength of 8.5 MV/cm with 90% yield, thereby enabling the manufacture of high performance p-channel devices like the IGBT.

scholarly journals EVALUATION OF DIELECTRIC STRENGTH OF EPDM ELASTOMER LOADED WITH ATH FILLER

2020 ◽  
Vol 4 (3) ◽  
pp. 13-18
Author(s):  
Tamer Sheta ◽  
A.Hossam Gad ◽  
L.S. Nasrat ◽  
S.M. El-Debeiky
Keyword(s):  
High Temperature ◽  
Electrical Properties ◽  
Thermal Conditions ◽  
Dielectric Strength ◽  
Microscopic Structure ◽  
Ethylene Propylene Diene Monomer ◽  
Climate Conditions ◽  
Ethylene Propylene ◽  
Alumina Trihydrate ◽  
Composite Samples

Ethylene Propylene Diene Monomer (EPDM) electrical properties are improved by adding Alumina Trihydrate (ATH) filler. Composite of EPDM with ATH filler are prepared with 10%, 20%, 30% and 40% percentages of concentration. The dielectric strength of the composite samples are tested under various thermal conditions such as (25, 70,100 and 130) ᵒC to simulate the various types of climates and clarify the effect of high temperature on the electrical properties of elastomers. Composite samples were exposed also to different climate conditions such as wet and salt. The obtained results of the composite performance are analyzed and discussed in the light of the variations of the material microscopic structure.  

Dielectric strength of Al2O3/silicone composites after high-temperature aging

2014 ◽  
Vol 131 (23) ◽  
pp. n/a-n/a ◽  
Author(s):  
Yiying Yao ◽  
Zheng Chen ◽  
Guo-Quan Lu ◽  
Dushan Boroyevich ◽  
Khai D. T. Ngo
Keyword(s):  
High Temperature ◽  
Dielectric Strength ◽  
High Temperature Aging ◽  
Temperature Aging
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