bluuebunny/crossref_metadata_2025_split huggingface dataset:
The influence of carbon additions on structure and properties of composites manufactured via powder metallurgy method
Authors: Hekner Bartosz , Myalski Jerzy 
Published: October 2015

This paper presents an influence of reinforcement and additions types on tribological properties for composite materials produced for potential application in high loaded friction point. The influence of carbon nanotubes or amorphous form of carbon on tribological properties was subject of authors' interest. A technology of materials manufacturing based on preparation of composite powders using high energy ball milling, with subsequent hot pressing in the semi-liquid phase. All materials based on an aluminum alloys, with silicon carbide (SiC) or silicon nitride particles (Si3N4) applied as a reinforcement. As a additions 1 wt.% of multiwalled carbon nanotubes (CNT) or 5 wt.% of glassy carbon particles (GCp) were used. A proper parameters selection (speed, powder to ball ratio, time ect.) of high energy milling led to fragmentation of ceramic particles up to nano- or submicro scale with desirable homogenization in whole volume of solid material. Due to partially crushed of glassy carbon particles, their size was between 2 – 200 μm. However GCp revealed also proper distribution in volume of composite. Moreover, the good quality of bonding between matrix and reinforcement particles were achieved due to high energy during milling.
For manufactured materials a rating of tribological properties (coefficient of friction, wear rate, ect.) at ambient and high temperature were made. The research confirmed that, due to desirable coefficient of friction (COF) value and low mass loss, manufactured materials can be applied in automotive industry, eg. for brake pads. A high stability of COF on desirable value (0.5 – 0.8) was observed up to temperature higher than 500 °C. The application of carbon additions resulted in increasing of friction properties. The material with silicon nitride as a reinforcement and glassy carbon particles addition revealed the best friction properties between analysed materials.
NiC: a highly sensitive functional layer based on a nickel/graphene thin film for pressure and force sensors.
Authors: Koppert Ralf 
Published: October 2015

A functional layer based on nickel and graphene called NiC was developed with the goal of a high strain sensitivity in combination with an adjustable temperature coefficient of resistance (TCR). A gauge factor up to 30 and TCR values of approximately 0±25 ppm/K can be achieved by variation of the film composition. Based on the increased sensitivity the important pressure range of below 2.5 bar is opened up for steel membrane pressure sensors without the need of a sophisticated technical effort.
First pressure and force sensors with NiC functional layers were realized in order to demonstrate the high performance of this new material. The enlarged sensitivity of the film leads to a complex re-development of the microsystems “pressure and force sensors” in order to take the advantage of the high linearity, low hysteresis, high overload protection and stability. Due to the high sensitivity, it is possible to produce sensors with significantly increased stability values in the overload region. Using the same output voltage range as usual with NiCr thin film elements, the overload capability of the sensors with the new functional layer is about twenty times the characteristic value of NiCr sensors. On the other hand, the low pressure range is opened up since the membrane needs to be deformed only one tenth of its usual value. Because of this low stress the load cycle stability increases accordingly. Additionally base body materials like 1.4435 (316L), which are not very suitable for the production of pressure sensor membranes, can be used for example for hydrogen applications.
Transient Liquid Phase Soldering for lead-free joining of power electronic modules in high temperature applications
Authors: Ehrhardt Christian , Hutter Matthias , Oppermann Hermann , Lang Klaus-Dieter 
Published: October 2015

The study focuses on a new variant of transient liquid phase soldering (TLPS) using tin based solder with copper powder. This technology may act as an alternative for lead free joining of semiconductor dies in power electronic applications at high operating temperature. Lead-free joining technologies currently used like gold-rich solders and silver sintering are well suited for high temperature applications. However, due to the high metal price they have a limited acceptance.
Using a special soldering process it is feasible to produce an almost void-less solder joint, using a paste of tin-based solder powder (e.g. SAC305), copper powder and a solvent which is hardly activated. The resulting interconnection is characterized by an almost complete transformation into intermetallic phases of Cu6Sn5 and Cu3Sn. Thus the melting point of the transformed interconnect can be increased up to the decomposition temperature of the Cu6Sn5 intermetallic phase which is 415 °C. A two-step soldering process allows to eliminating the typical skeleton structure that forms as a result of the immediate reaction of the liquid tin-based solder with the higher melted copper powder to form the Cu6Sn5 and Cu3Sn intermetallic phases. An alternative way compared to the two-step-process is also explained in this study: Capillary forces let the solder flow into the gap filled with Cu spheres.
End of Life Failure Modes for Packaged SOI Devices for Signal Conditioning and Processing Applications
Authors: Riches S T , Johnston C , Crossley A , Grant P 
Published: October 2015

Silicon on Insulator (SOI) device technology has been shown to be capable of functioning satisfactorily at operating temperatures of &gt;200°C. Most of the applications to date have required performance for short times (&lt;2,000 hours) at the highest operating temperatures of up to 225°C in down-well drilling applications. There is interest in extending the endurance of high temperature electronics into aero-engine and other applications where a minimum 20 year operating life is stipulated. In order to gain confidence in high temperature electronics that can meet this requirement, accurate reliability data are needed and end of life failure modes need to be identified. Most of the reliability data on the high temperature endurance of the integrated circuit is generated with little consideration of the packaging technologies, whilst most of the reliability data pertinent to high temperature packaging technologies uses test pieces rather than devices, which limits any conclusions relating to long term electrical performance.
This paper presents results of temperature storage and cycling endurance studies on SOI devices combined with high temperature packaging technologies relevant to signal conditioning and processing functions for sensors in down-well and aero-engine applications. The endurance studies have been carried out for up to 11,088 hours at 250°C, with functioning devices being tested periodically at room temperature, 125°C and 250°C and rapid thermal cycling from −40°C to +225°C. Different die attach and wire bond options have been included in the study and the performance of several functional blocks on the SOI device has been tracked over the endurance tests. The failure modes observed on completion of the endurance tests include die cracking and deterioration of the device bond pads accelerated due to degradation of some die attach materials. The routes to achieving stable long term performance of packaged devices at temperatures of 250°C will be outlined.
Combined Temperature and Vibration Testing for Wire Bond Interconnections in Harsh Environment Electronics
Authors: Mirgkizoudi M. , Liu C. , Conway P. , Riches S. 
Published: October 2015

The performance of electronics located in harsh environments is often affected by a combination of environmental factors. Qualification tests on such electronics are normally carried out by separate environmental tests such as temperature storage, temperature cycling and vibration tests. This approach may mask the effects of combined parameters, where degradation in a vibration environment may be accelerated by temperature related effects on material properties, for example.
This paper presents details of an initial study into the combined effects of temperature and vibration on wire bonded interconnections used in the production of high temperature electronic components. The study is focused on the testing of electronic components under the combination of temperature exposure up to 250°C and vibration loading with a frequency range between 50Hz and 2000Hz and acceleration up to 20g rms. The study covers the fundamental aspects of wire bond connections and their failure mechanisms, where the effect of wire loop height and length under separate and combined vibration and temperature tests has been investigated. The study has also assessed the effect on packaged silicon on insulator (SOI) devices assembled into ceramic packages under representative combined temperature and vibration profiles. The work has shown that the combined effect of temperature and vibration has increased the susceptibility of wire bond interconnections to vibration induced failures and vibration testing under the applied temperature is recommended for assessment of components for harsh environments.
The Behaviour of Au-Au Wire Bonds in Extreme Environments
Authors: Shepherd D. , Grant P.S. , Johnston C. , Riches S. 
Published: October 2015

Microelectronics are being required to show high reliability within aero-engines, oil-gas wells and other extreme applications where devices can experience over 250°C, 1000bar, corrosive environments and significant vibration. Currently operation may be only possible for a small number of hours, which necessitates expensive shut-down and replacement.
Wire bond interconnects continue to be critical to overall reliability though previous studies have shown that traditional Au-Al bonds fail in such environments due to microstructural instability. Au-Au bonds offer a potentially stable solution that is increasingly desirable as microelectronics are required to endure ever harsher conditions.
Au ball bonds on two representative substrates with Au surfaces and ceramic bases have been exposed to 250 and 300°C in N2 for up to 2000 hours. Substrate 1 was a high temperature co-fired ceramic (HTCC) with a Au coating above Ni-Co and W layers, and Substrate 2 was a Au thick film on alumina.
Wire pull and ball shear tests for both sample types significantly exceeded industry specifications, though a decrease in yield strength was observed. Key samples were cross-sectioned and grain structure was revealed by ion channelling contrast within a focused ion beam (FIB) system.
The yield strength decrease was attributed to the Hall-Petch effect through elimination of twin grains formed during bonding deformation. Electron probe microanalysis (EPMA) of underlying Ni showed little interdiffusion into the Au. Hence the mechanical robustness and microstructural stability of Au-Au wire bonds in extreme environments has been demonstrated and understanding of thermal ageing mechanisms has been improved.
A Universal BCD-on-SOI Based High Temperature Short Circuit Protection for SiC Power Switches
Authors: Zuo Liang , Islam S. K. , Huque M. A. , Su C. , Blalock B. J. , Tolbert L. M. 
Published: October 2015

In recent years, the rapid increase in the market for hybrid electric vehicles has generated great demand for low-cost, high-volume, high-temperature power converters that can work in harsh environment (temperature ≥ 150°C) conditions. Most of the commercially available power semiconductor devices and associated control electronics are rated for maximum of 85°C ambient temperature. Under this circumstance, wide bandgap (WBG) semiconductors have become a better alternative due to their ability to operate at much higher temperatures (≥500°C) than conventional bulk silicon based devices. As with any other power devices, SiC switches also require fault detection and protection mechanisms for their reliable application to real systems. One severe fault situation is the short circuit at the load end, which can cause very high surge currents that flow through the power switches. Quick detection and removal of the short circuit fault current by external circuitry is required to protect the power switch as well as the power converter module.
This work presents a high-temperature (≥200°C), high-voltage short circuit protection (SCP) for SiC power devices. The circuit is designed using a resistor sensing method to provide protections for both “normally ON” and “normally OFF” SiC FET switches. A rail-to-rail input comparator is employed to ensure that the circuit operates under different power supply levels. The prototype circuit is implemented using a 0.8-micron, 2-poly, and 3-metal BCD-on-SOI process. The die size for the protection circuit is 0.52 mm2 (845 μm × 612 μm). The circuit has been successfully tested up to 200°C ambient temperature under power supplies ranging from 10 V to 30 V without any heat sink or cooling mechanism.
Metallurgy for SiC Die Attach for Operation at 500°C
Authors: Zheng Ping , Henson Phillip , Johnson R. Wayne , Chen Liangyu 
Published: October 2015

Metallurgy for high temperature SiC die attach involves the substrate metallization, die metallization, and die attach material. This paper examines off-eutectic Au-Sn as the die attach alloy with a PtAu thick film metallization on AlN substrates. A pure Au thick film layer was printed over the PtAu thick film layer. The SiC backside metallizations evaluated were Ti/TaSi/Pt/Au and Cr/NiCr/Au. Die shear tests were performed after aging at 500°C and after thermal cycling. The shear test results and failure surface analysis are discussed.
Nanoparticle Ag and liquid transient phase bonding with Ag based metallurgies have been proposed for high temperature die attach. Data on the migration of sintered nano-particle Ag and thin film Ag dc bias during storage in air at 300°C and 375°C are presented. Migration of Ag is a potential failure mechanism for Ag based high temperature metallurgies.
Characterization of Circuit Blocks for Configurable Analog-Front-End
Authors: Ohme Bruce W. , Larson Mark R. , Tulpule Bhal , Behbahani Alireza 
Published: October 2015

Analog functions have been implemented in a Silicon-on-Insulator (SOI) process optimized for high-temperature (&gt;225°C) operation. These include a linear regulator/reference block that supports input voltages up to 50V and provides multiple independent voltage outputs. Additional blocks provide configurable sensor excitation levels of up to 10V DC and/or 20V AC-differential, with current limiting and monitoring. A dual-channel Programmable-Gain-Instrumentation Amplifier (PGIA) and a high-level AC input block with programmable gain and offset serve signal conditioning, gain, and scaling needs. A multiplexer and analog buffer provide an output that is scaled and centered for down-stream A-to-D conversion.
Limited component availability and high component counts deter development of sensing and control electronics for extreme temperature (&gt;200°) applications. Systems require front-end power conditioning, sensor excitation and monitoring, response amplification, scaling, and multiplexing. Back-end Analog-to-Digital conversion and digital processing/control can be implemented using one or two integrated circuit chips, whereas the front-end functions require component counts in the dozens.
The low level of integration in the available portfolio of SOI devices results in high component count when constructing signal conditioning interfaces for aerospace sensors. These include quasi-DC sensors such as thermo-couples, strain-gauges, bridge transducers as well as AC-coupled sensors and position transducers, such as Linear Variable Differential Transducers (LVDT's). Furthermore, a majority of sensor applications are best served by excitation/response voltage ranges that typically exceed the voltage range of digital electronics (either 5V or 3.3V in currently available digital IC's for use above 200°C). These constraints led Embedded Systems LLC to design a generic device which was implemented by Honeywell as an analog ASIC (Application Specific Integrated Circuit).
This paper will describe the ASIC block-level capabilities in the context of the typical applications and present characterization data from wafer-level testing at the target temperature range (225C).
This material is based upon work performed by Honeywell International under a subcontract from Embedded Systems LLC, funding for which was provided by the U.S. Air Force Small Business Innovative Research program.
High Temperature 0.35 Micron Silicon-on-Insulator CMOS Technology
Authors: Kappert Holger , Dreiner Stefan , Dittrich Dirk , Grella Katharina , Kelberer Andreas , Klusmann Miriam , Kordas Norbert , Kosfeld Andre , Schmidt Alexander , Paschen Uwe , Kokozinski Rainer 
Published: October 2015

Silicon-on-Insulator (SOI) is the most commonly used technology for integrated circuits capable of operating at high temperature. Due to the efficient reduction of leakage current paths much higher operation temperatures are achievable with SOI than with bulk technologies. Published work on high temperature CMOS circuits typically refers to technologies with a minimum feature size of 0.8 to 1.0 micron [1][2][3] even though for complex digital circuits this results in large die size. Technologies with smaller feature size are available but typically not suitable for reliable high temperature operation due to high leakage currents, decreasing threshold voltages over temperature or reliability issues with the standard aluminum metallization.
Fraunhofer IMS has developed a high temperature 0.35 micron thin film SOI technology. The mixed signal technology provides numerous devices, e.g. specific transistors for analog and digital circuit design, diodes, resistors and voltage independent capacitors. Also non-volatile memory cells (EEPROM) are available. In addition the technology is equipped with a tungsten metallization for highly reliable operation even at high temperatures. An overview on the new technology including characterization results of devices and test circuits is given in this paper.
A 200 °C Motor Control ASIC
Authors: Majerus Steve J. A. , Goff Daniel T. , Merrill Walter 
Published: October 2015

A custom application-specific integrated circuit (ASIC) has been designed for positional control of brushless DC or servo motors in high-temperature (&gt;200 °C) environments. Applications would include valve and position control for aerospace and industrial systems. Patented high-temperature circuit design techniques facilitate hightemperature operation from a conventional, low-cost, 0.5-micron bulk CMOS foundry process. The ASIC is highly integrated to enable software- and processor-free local control of motor position, and uses external power MOSFETs for motor commutation. Motor position can be controlled in open- or closed-loop modes with an integrated rotational variable displacement transformer (RVDT) direct digital synthesis (DDS) waveform generator, rail-to-rail op-amp driver and demodulation circuit. The ASIC can accept both analog (0–10 V) or digital (SPI bus) position setpoint commands from an external controller. Motor position is indicated by both analog and digital output signals. The full-scale displacement of the controlled motor is programmable from 5 to 8 bits of resolution, permitting 32–256 positions of control. Safety features such as a 500-ms power-on delay, overtemperature and motor overcurrent detection, and control signal undervoltage lockout were included to minimize the need for external control.
ASIC bench-test results confirmed circuit functionality at ambient temperatures up to 225 °C using room-temperature power MOSFETs and motor load. ASIC performance at the 8-bit level was demonstrated, although the clock oscillator frequency shifted by about 15% over the full temperature range. Control of the motor at 200 °C was also demonstrated, although moderate loss of motor holding torque was observed due to internal heat generation in the motor. The ASIC was combined with commercially-available off-the-shelf high-temperature components on a printed wiring board (PWB) to form a compact (4 × 3.5 inch) motor control demonstration system capable of prolonged operation at temperatures beyond 200 °C. Environmental and long-term testing of the PWB is planned to demonstrate system reliability.
Highly Integrated and Isolated Universal Half-Bridge Power Gate Driver and Associated Flyback Power Supply for High Temperature and High Reliability Applications
Authors: Gras David , Pautrel Christophe , Fanaei Amir , Thepaut Gregory , Chabert Maxime , Laplace Fabien , Picun Gonzalo 
Published: October 2015

In this paper we present a highly integrated, high-temperature isolated, half-bridge power gate driver demo board, based on turnkey X-REL chipset: XTR26010 (High-Temperature Intelligent Gate Driver), XTR40010 (High-Temperature Isolated Two Channel Transceiver), XTR30010 (High-Temperature PWM Controller), and XTR2N0825 (High-Temperature 80V N-Channel Power MOSFET).
The XTR26010 is the key circuit in this chipset for power gate drive application. The XTR26010 circuit has been designed with a high focus in offering a robust, reliable and efficient solution for driving a large variety of high-temperature, high-voltage, and high-efficiency power transistors (SiC, GaN, Si) existing in the market. Furthermore, the XTR26010 circuit implements an unprecedented functionality for high-temperature drivers allowing safe operation at system level by preventing any cross-conduction between high-side and low-side switches, through isolated communication between high-side and low-side drivers.
The XTR40010 is used for isolated data communication between a microcontroller or a PWM controller with the power driver (XTR26010).
For supplying the half-bridge gate driver, a compact isolated flyback power supply has been developed thanks to the versatile voltage mode PWM controller XTR30010 and the XT2N0825 N-Channel MOSFET. The full system has been successfully tested while driving different brands of SiC MOSFETs up to Ta=200°C, 600kHz of switching frequency and 600V high-voltage bus (limited by isolation transformers used). The demo board presented can be easily modified to drive other SiC and GaN transistors available in the market. The 200°C limitation of the demo board is due to passives, PCB material, and the solder paste used. However, all X-REL active circuits have been qualified within specifications well above 230°C.