bluuebunny/crossref_metadata_2025_split huggingface dataset:
High Temperature Lithium Alloy Cells With Improved Low Temperature Performance
Authors: Johnson Arden P. , Wang Cuiyang , Miller John S. 
Published: October 2015

Lithium-thionyl chloride cells are widely used in downhole applications where the temperatures exceed 100°C. These cells cannot be used above the melting point of lithium, 180°C, but modified oxyhalide cells are available that use higher-melting lithium alloy anodes that allow safe operation at temperatures as high as 200°C. However, the higher temperature capability comes at the cost of low temperature performance; the alloy cells typically show very poor rate capability below 50°C. The low temperature rate limitations can be particularly disadvantageous in cases where a tool is started up at the surface, where the ambient temperatures are cooler, before it is placed into operation downhole.
Here we present test results defining and characterizing the capabilities and limitations of various types of lithium alloy cells at lower temperatures, as well as discharge results at higher temperatures for new cell types that have been designed for improved rate capability at both lower and higher temperatures.
Rugged ICs against Corrosion, Shock plus Hotter Temperatures
Authors: Wang James J. 
Published: October 2015

More applications need microcontrollers to operate at higher temperatures. ICs must survive faster corrosion rate and higher stresses. Improving wire bonding, mold compound or package design requires engineering effort, long evaluation and cost. Because packages are already optimized, further optimization often does not yield the needed improvements. Without changing either chip design or the packaging, one can achieve high temperature reliability by protecting ICs with a gold, over passivation metal (OPM).
Low cost CMOS liquid crystal display driver ICs are plated with gold bumps at high volume. Similar gold plating process can be quickly and cheaply implemented over all microcontrollers. Between ICs to the electroplated gold OPM is a barrier metal that slows gold diffusion into aluminum and thereby increases operating life before Au-Al intermetallic wire bond failure. Reliability is improved 6x to 94x under different test conditions.
Ball bonding to gold pads are 10% to 40% stronger than onto aluminum pads. Furthermore, gold-gold mono-metallic bonds are ductile and can withstand stresses of extreme package reliability tests consisting of: AATC, MSL1 preconditioning, autoclave and then 190C HTB for 1000 hours. Ductile bonds can strain under mechanical stress and shock. Gold is resistant against corrosion such that packaged ICs survive reliability tests causing mold compound delamination and then moisture ingress from autoclave.
Performance of commercial SOI driver in harsh conditions (up to 200°C)
Authors: El Falahi K. , Allard B. , Tournier D. , Bergogne D. 
Published: October 2015

Power electronics based on wide band gap materials, such as silicon carbide (SiC) or gallium nitride (GaN), are nowadays capable of operation at increased ambient temperatures. High Temperature Intelligent Power Modules are unfortunately not available due to a lack of integrated driver able to withstand either harsh environment or enhanced junction temperature due to reduction in the cooling system. The most appropriated technology for such a driver seems to be Silicon on Insulator (SOI). The maximum operating temperature of commercial SOI devices with conventional packaging is usually 150°C up to 175°C as specified by manufacturers. In this paper, we actually try to observe the performance and de-ratings of these SOI circuits at temperatures above 175°C.
Experimental characterization of commercial SOI MOSFET drivers from room temperature to 200°C and beyond is presented. Parameters such as output current amplitude, delay time, rise time and fall time of the output waveforms of the drivers are monitored. The test results will be discussed, and will help produce the specifications of an integrated SOI-based core-driver with the necessary functionalities to drive an inverter up to 220°C ambient temperature.
High Temperature Capacitors Based on [0001] and [1120] Sapphire Dielectrics
Authors: Chen Liang-Yu 
Published: October 2015

The test results of the dielectric properties of [0001] (C-plane) and [1120] (A-plane) sapphire (single crystalline Al2O3) at high temperatures indicate that these materials have very stable dielectric constants and low dielectric losses (compared with polycrystalline alumina) at low frequencies in the temperature range from room temperature to 550°C. Therefore, sapphire materials have become likely candidate dielectric materials for high temperature capacitors. This paper reports prototype low-volume (∼100pF) capacitors based on sapphire dielectrics for high temperature and low frequency applications.
Low-volume parallel-plate capacitors using C-plane and A-plane sapphire as dielectric material were fabricated by stacking metallized sapphire substrates. These prototype capacitors were characterized in the temperature range from room temperature to 550°C by measuring the capacitance and parallel resistance of these devices at 120Hz, 1kHz, 10kHz, 100kHz, and 1MHz. The capacitance and equivalent parallel resistance of these capacitors were all directly measured by an AC LCZ impedance meter in controlled temperature environments.
These prototype devices demonstrate stable capacitances over a wide temperature range, and therefore, have the potential to be integrated with silicon carbide (SiC) devices to enable high temperature electronics. The needs of thin-film metallization and encapsulation for these sapphire substrates are also discussed.
Demonstrated Performance Characteristics For Improved High Temperature Ceramic Capacitors Intended For Use In Extreme, Harsh Environments
Authors: Syammach Mustafa A. , Roach Michael J. , Syammach Fauzi A. , Habibi Mustapha 
Published: October 2015

Availability of a reliable and consistent source for high temperature ceramic capacitors has been an ongoing issue for design engineers looking at developing product for applications up to and including +300°C. The general practice has been to derate standard X7R ceramic capacitors for high temperature applications and settle for a device characterized by a significant reduction in those critical performance features related to capacitance value, operating voltage, insulation resistance and breakdown voltage, not to mention a substantial roll off in temperature coefficient above +150°C. In addition, the need to provide coated and / or leaded options also presents additional concerns related to operational integrity.
This paper presents packaging options, life test reliability data and compares performance characteristics for a unique high K, high temperature ceramic capacitor, to the more traditional options. This approach utilizes leading edge, Class II dielectric and packaging materials that have been specifically developed for use at +300°C and then benefit from enhanced reliability when operated at lower temperatures. As shown in this paper, capacitors manufactured with this dielectric material exhibit much higher capacitance per unit volume and significant improvements in insulation resistance, without having to sacrifice mechanical strength, voltage rating or long term reliability.
New High Temperature Electronic Components for Power Management and Motor Control Applications
Authors: Delatte Pierre , Dessard V. , Saib A. , Pequignot N. , Picún G. , Demeûs L. , Martinez L. , Krebs T. , Doucet J.-C. 
Published: October 2015

This paper presenst CISSOID's new high temperature chips for Power Management and Motor Control in automotive, oil & gas, aerospace and industrial applications.
High temperature DC-DC reference designs, called respectively ETNA, VESUVIO™ and EREBUS™, have been announced recently. These Buck (step-down) DC-DC converters are built with proven CISSOID products as active components rated from −55°C up to 225°C. These DC-DC converters can have input voltages from 6V up to 50V. The output voltage can be adjusted from 10% up to 90% of the input voltage. Power efficiencies in excess of 90% above 200°C have been demonstrated. VESUVIO™ and EREBUS™ are based on MAGMA PWM controller, HYPERION half-bridge driver and two power transistors to implement a synchronous Buck converter.
For high voltage and power levels, new Silicon-Carbide devices allow operating at high junction temperatures. They enable high power modules with higher densities in terms of size and weight. Having power drivers able to operate very close to these devices allow further integration of power modules while increasing the performances thanks to lower parasitic capacitances and inductances. This will also ease to increase switching frequencies, another key advantage of these new devices. For these applications, CISSOID has released PROMETHEUS I Power Driver reference design that can sink and source currents up to 2Amps at a supply voltage from 11V up to 30V. Recently announced PROMETHEUS II design, based on HYPERION driver, enables rise and fall times of 25ns on a 1nF load.
Application of High Temperature Electronics Packaging Technology to Signal Conditioning and Processing Circuits
Authors: Riches S T , Cannon K , Johnston C , Sousa M , Grant P , Gulliver J , Langley M , Pittson R , Serban S , Baghurst D , Firmstone M 
Published: October 2015

The requirement to install electronic power and control systems in high temperature environments has posed a challenge to the traditional limit of 125°C for high temperature exposure of electronics systems. The leap in operating temperature to above 200°C in combination with high pressures, vibrations and potentially corrosive environments means that different semiconductors, passives, circuit boards and assembly processes will be needed to fulfil the target performance specifications.
Bare die mounted onto ceramic and insulated metal substrates can withstand higher temperatures than soldered surface mount devices on printed circuit boards. The results of the evaluation of electronic interconnect and substrate materials that have been submitted to temperatures of 250°C for up to 2000 hours will be presented, including details on novel adhesive formulations and high temperature insulated metal substrates. The materials and processes developed have been applied to the manufacture of high temperature circuits representative of analogue signal conditioning and processing, using silicon on insulator devices and passive components mounted into HTCC packages and onto thick film on ceramic substrates. Results of the characterisation of these devices and circuits at temperatures of 250°C for up to 2000 hours will be presented.
This work forms part of the UPTEMP project has been set-up with support from UK Technology Strategy Board and the EPSRC, which started in March 2007 with 3 years duration. The project brings together a consortium of end-users (Sondex Wireline and Vibro-Meter UK), electronic module manufacturers (GE Aviation Systems Newmarket) and material suppliers (Gwent Electronic Materials and Thermastrate Ltd) with Oxford University-Materials Department, the leading UK high temperature electronics research centre.
Microstructural Evolution and Thermal Stability Characterization of a High Temperature Die Attach Lead-Free System
Authors: Rodriguez Rogie I. , Ibitayo Dimeji , Quintero Pedro 
Published: October 2015

There is a need for electromechanical devices capable of operating in high temperature environments (&gt;200°C) for a wide variety of applications. Today's wide-bandgap (WBG) semiconductor based power electronics have demonstrated a potential of operating above 400°C, however they are still limited by packaging. Among the most promising alternative is the Au-Sn eutectic solder, which have been widely used due to its excellent mechanical and thermal properties. However, the operating temperature of this metallurgical system is still limited to ∼250°C owing to its melting temperature of 280°C. Therefore, a higher temperature resistant system is much needed, but without affecting the current processing temperature of ∼325°C typically exhibited in most high temperature Pb-Free solders.
This paper presents the development and characterization of a fluxless die attach soldering process based on gold enriched solid liquid inter-diffusion (SLID). A low melting point material (eutectic Au-Sn) was deposited in the face of a substrate, whereas a high melting point material, gold in this instance, was deposited in its mating substrate. Deposition of all materials was performed using a jet vapor deposition (JVD) equipment where thicknesses were controlled to achieve specific compositions in the mixture. Sandwiched coupons where isothermally processed in a vacuum reflow furnace. SEM and EDS were employed to reveal the microstructural evolution of the samples in order to study the interfacial reactions of this fluxless bonding process. Mechanical characterization of the each individual intermetallic phase was achieved by nanoindentation. Differential scanning calorimetry demonstrated the progression of the SLID process by quantifying the remaining low melting point constituent as a function of time and temperature. Post-processed samples confirmed the inter-diffusion mechanism as evidenced by the formation of sound joints that proved to be thermally stable up to ∼490°C after the completion of the SLID process.
Platform for Testing Sensors in HT Geothermal Wells
Authors: Normann Randy 
Published: October 2015

This paper describes a logging tool designed for testing new high-temperature aircraft engine sensors deep inside hot geothermal wells. The tool is a complete logging system ready for field testing with a continuous well exposure rating of 10,000 psi and 275 °C. The tool was designed backwards giving engineers of experimental sensors complete access to the front of the logging tool for well access.
As described in this paper, Perma Works provides a simple electrical interface providing power, sensor reference voltage and data channels. Sensor engineers can transmit their data via Perma Works open data channels OR access the logging cable to monitor sensor dynamic signals.
Surface software is easy to modify to record the sensor readings during the well log. The reader will learn more about geothermal logging tools and how the Perma Works tool can aid aircraft engine sensor developers open new markets by proving their sensors in some of the harshest conditions on Earth.
The melting-point increase of Sn-Bi solder joint by Cu particles addition
Authors: Mokhtari Omid , Nishikawa Hiroshi 
Published: October 2015

Solder is one of the main materials for interconnects in microelectronic packaging and Sn-Pb solder alloys have been the most common solders for a long time. However, the use of Pb has been very limited because of the negative effects of Pb on the human health and the environment. Therefore, Sn-Bi based solders were recommended as a low temperature solder to replace Sn-Pb solders because of their low temperature melting point. Low temperature melting point of Sn-Bi solders reduces the damage due to the thermal effect of the high temperature on the mechanical properties of the joints. However, its low melting point allows Sn-Bi solders to be used in a limited range of applications. The objective of this research is to enable the Sn-Bi based solders to be used in higher temperature applications. Therefore, this research represents how to increase the melting point of the solder joint after the reflow while keeping the advantage of low melting point before the reflow.
The method which was tried in this research in order to increase the melting point of the Sn-Bi solder after the reflow is to convert the whole Sn phase of the solder to Cu6Sn5 and Cu3Sn intermetallics by adding Cu particles to the solder before the reflow. The binary Sn-Bi and Sn-Bi + 30 wt. %Cu particles were investigated in this research. Scanning electron microscopy (SEM) and electron probe micro-analyzer (EPMA) were used to examine the microstructure of the solder parts after the reflow. Various reflow profiles were tried to enable the whole Sn phase react with the added Cu particles. Differential scanning calorimetry (DSC) was also used in this research to investigate the melting point of the solder parts. The results after the reflow at 230°C for 50 min show that almost all Sn phase was successfully converted to the Cu6Sn5 and Cu3Sn phase.
Digital and Analogue Integrated Circuits in Silicon Carbide for High Temperature Operation
Authors: Ramsay E.P , Clark D.T. , Cormack J.D. , Murphy A.E. , Smith D.A , Thompson R.F. , Young R.A.R. , Finney S. 
Published: October 2015

A need for high temperature integrated circuits is emerging in a number of application areas. As Silicon Carbide power discrete devices become more widely available, there is a growing need for control ICs capable of operating at the same temperatures and mounted on the same modules. Also, the use of high temperature sensors, in, for example, aero engines and in deep hydrocarbon and geothermal drilling applications results in a demand for high temperature sensor interface ICs.
This paper presents new results on a range of simple logic and analogue circuits fabricated on a developing Silicon Carbide CMOS process which is intended for mixed signal integrated circuit applications such as those above.
A small family of logic circuits, pin compatible with the 74xx series TTL logic parts, has been designed, fabricated and tested and includes, for example, a Quad Nand gate and a Dual D-type flip-flop. These have been found to be functional from room temperature up to 400°C. Analogue blocks have been investigated with a view to using switched capacitor or autozero techniques to compensate for temperature and time induced drifts, allowing very high temperature operation.
The Effects of Repeated Refresh Cycles on the Oxide Integrity of EEPROM Memories at High Temperature
Authors: Reed Lynn , Reddy Vema 
Published: October 2015

Data retention in stored-charge based memories, such as Flash and EEPROMs, decreases with increasing temperature. Compensation for this shortening of retention time can be accomplished by refreshing the data using periodic erase-write refresh cycles, although the number of these cycles is limited by oxide integrity. An alternate approach is to use refresh cycles consisting of a rewrite only cycles, without the prior erase cycle. The viability of this approach requires that this refresh cycle induces less damage than an erase-write cycle. This paper studies the effects of repeated refresh cycles on oxide integrity in a high temperature environment and makes comparisons to the damage caused by erase-write cycles.
The experiment consisted of running a large number of refresh cycles on a selected byte. The control group was other bytes which were not subjected to refresh only cycles. The oxide integrity was checked by performing repeated erase-write cycles on each of the two groups to determine if the refresh cycles decreased the number of erase-write cycles before failure. Data was collected from multiple parts, with different numbers of refresh cycles, and at temperatures ranging from 25C to 190C.
The experiment was conducted on microcontrollers containing embedded EEPROM memories. The microcontrollers were programmed to test and measure their own memories, and to report the results to an external controller. This greatly simplified the hardware setup, since only six wires were required to operate and test the memories of 77 microcontrollers. It also allowed data collection from the microcontrollers while the experiment was in progress.
Data is presented showing that refresh cycles do not have a significant impact on oxide integrity. This result shows that the refresh cycle approach will not degrade the oxide and suggests that it will provide a mechanism to extend data retention at high temperatures without affecting device reliability.
The data also showed a bimodal distribution of the number of erase-write cycles necessary to damage the oxide. Although the cause of this distribution is not yet understood, it may provide an additional means to significantly improve EEPROM reliability through appropriate screening.
230C Hermetically Sealed SMD Tantalum Capacitors
Authors: Zednicek T. , Biler M. , Petrzilek J. , Pinwill I. , Faltus R. 
Published: October 2015

Certain electronic applications, such as oil and gas exploration drilling, are continuously demanding ever higher operating temperatures. Recently operating temperature requirements have increased from 200°C to 230°C with an increased operating life from hours to one thousand hours and beyond. This need is linked with the continuous development of oil drilling heads and sensors and their use for deeper drilling or drilling in more difficult geological conditions. Capacitors with high capacitance value are a common part of the electronic boards used in these applications, but over 125°C/175°C, available capacitor choice is very limited. Tantalum SMD capacitor technology has proved its reliability in operation up to 175°C and there is a limited choice of special designs up to 200°C. Long life wet tantalum capacitors up to 200°C are available from multiple sources, or up to 230°C with reduced operational life from a single source.
Hermetically sealed MnO2 tantalum capacitors have demonstrated their ability to offer unique long life stability at 230C combined with solid, stable and robust design. [1]. The next testing and development presented in this paper discusses the basic behavior of the solid hermetically sealed MnO2 tantalum capacitor above 200°C. A certain type of “wear out” has been observed in a longer exposure at 230°C depending on applied voltage. Nevertheless, the basic capability of the capacitor meets the “best in class” requirement for 230°C 1000hours continuous operating life with 50% voltage derating. The paper discusses and summarizes the “wear out” phenomenon observed at temperatures above 200°C on these capacitors and impact of different voltage derating to operational life at 230°C .
Long Term Demonstrated Performance Characteristics for Improved High Temperature Ceramic Capacitors Intended for Use in Extreme, Harsh Environments
Authors: Syammach Mustafa A. , Habibi Mustapha , Syammach Fauzi A. 
Published: October 2015

Availability of a reliable and consistent source for high temperature ceramic capacitors has been an ongoing issue for design engineers for the purpose of developing product for applications up to and including +300°C. The general practice has been to de-rate standard X7R ceramic capacitors for high temperature applications and settle for a device characterized by a significant reduction in the critical performance features related to capacitance value, operating voltage, insulation resistance and breakdown voltage, not to mention a substantial roll off in temperature coefficient above +150°C. In addition, the need to provide coated and / or leaded options also presents additional concerns related to operational integrity.
This paper presents packaging options, life tests reliability data and compares performance characteristics for a unique high K, high temperature ceramic capacitor, to the more traditional options. This approach utilizes leading edge, Class II dielectric and packaging materials that have been specifically developed for use at +300°C and then benefit from enhanced reliability when operated at lower temperatures. As shown in this paper, capacitors manufactured with this dielectric material exhibit much higher capacitance per unit volume and significant improvements in insulation resistance, without having to sacrifice mechanical strength, voltage rating or long term reliability.