High Temperature Electronics Research Articles

Materials for high-temperature digital electronics

Materials for high-temperature digital electronics

Ga2O3/NiO junction barrier Schottky diodes with ultra-low barrier TiN contact

Power Schottky barrier diodes (SBDs) face an inherent trade-off between forward conduction loss and reverse blocking capability. This limitation becomes more severe for ultra-wide bandgap (UWBG) SBDs due to the large junction field. A high Schottky barrier is usually required to suppress the reverse leakage current at the price of an increased forward voltage drop (VF). This work demonstrates a Ga2O3 junction barrier Schottky (JBS) diode that employs the embedded p-type NiO grids to move the peak electric field away from the Schottky junction, thereby allowing for the use of an ultra-low barrier TiN Schottky contact. This JBS diode concurrently realizes a low VF of 0.91 V (at forward current of 100 A/cm2) and a high breakdown voltage over 1 kV, with the VF being the lowest in all the reported vertical UWBG power diodes. Based on the device characteristics measured up to 200 °C, we further analyze the power loss of this JBS diode across a wide range of operational duty cycles and temperatures, which is found to outperform the TiN/Ga2O3 SBDs or NiO/Ga2O3 PN diodes. These findings underscore the potential of low-barrier UWBG JBS diodes for high-frequency, high-temperature power electronics applications.

Compare gallium nitride, silicon carbide and monocrystalline silicon: application scenarios and research status

This paper conducts a comprehensive analysis of gallium nitride (GaN), silicon carbide (SiC), and silicon (Si) in the electronics and power industries, highlighting their current applications and future trends. GaN emerges as a front-runner for high-speed switching with its high-frequency, high-efficiency characteristics, and its superior electron mobility and voltage endurance are vital for miniaturized, high-performance electronics. In contrast, SiC's robustness at high temperatures, superior thermal conductivity, and exceptional breakdown field strength make it the material of choice for high-power, high-temperature electronics, playing a pivotal role in LED lighting, renewable energy systems, and power grid technologies. While Si lags behind in high-temperature and high-power performance, its cost-effectiveness and mature manufacturing keep it significant in the market. Furthermore, the paper addresses the technical challenges and innovative solutions in switch component applications for SiC and GaN, such as gate drive issues, breakdown mechanism optimization, and Si's ongoing advancements in microelectronics. By examining the strengths and weaknesses of each material, future research directions are pinpointed, including material synthesis, device design, and system integration advancements, aiming to enhance their application performance and efficiency in the electronics and power sector. In summary, GaN, SiC, and Si each bring unique advantages to electronics and power applications, indicating a future of more efficient, reliable, and eco-friendly technological innovations in power electronics.

Prediction of NbTaTiZr-based high-entropy alloys with high strength or ductility: First-principles calculations

Refractory high-entropy alloys (RHEAs) have a great potential in high-temperature electronics, extensive aerospace and biomedical applications due to their unique strength and ductility. Herein, the effects of alloying elements on the mechanical and electronic properties of NbTaTiZrX (X = V, Mo, Hf, W and Re) RHEAs are investigated by using the density functional theory (DFT) in combination with the special quasi-random structure (SQS) and virtual crystal approximation (VCA) methods. The calculated results show that alloying of Mo, W and Re with high elastic modulus can enhance the strength and the hardness of RHEAs. Among them, NbTaTiZrRe RHEA with the best strengthening effect has a yield strength of exceeds 2 GPa, which is notably higher than other considered high-entropy alloys. For alloying of V and Hf, the ductility of RHEAs is improved, and among which, NbTaTiZrHf RHEA has a relatively best ductility. Compared with other NbTaTiZrX RHEAs, spiral dislocations in NbTaTiZrHf RHEA are more prone to nucleate, and which confirms its excellent ductility. Moreover, the reduction of pseudo energy gaps and the formation of Hf–Hf strong metallic bonds further confirm its metallic ductility from the electronic density of states and charge density. The theoretical predictions in this study are congruent with the existing experimental data, and have certain theoretical guidance relevance for enhancing the mechanical characteristics of NbTaTiZrX (X = V, Mo, Hf, W and Re) RHEAs.

An analog to digital converter in a SiC CMOS technology for high-temperature applications

Integrated circuits based on wide bandgap semiconductors are considered an attractive option for meeting the demand for high-temperature electronics. Here, we report an analog-to-digital converter fabricated in a silicon carbide complementary metal–oxide–semiconductor technology now available through Europractice. The MOSFET component in this technology was measured up to 500 °C, and the key parameters, such as threshold voltage, field-effect mobility, and channel-length modulation parameters, were extracted. A 4-bit flash data converter, consisting of 266 transistors, is implemented with this technology and demonstrates correct operation up to 400 °C. Finally, the gate oxide quality is investigated by time-dependent dielectric breakdown measurements at 500 °C. A field-acceleration factor of 4.4 dec/(MV/cm) is obtained by applying the E model.

Конструктивно-технологические особенности высокотемпературных интегральных микросхем

The problems of design and technological solutions for high-temperature analog microcircuits have been studied. Based on a review of publications devoted to the problems of designing high-temperature electronics products, it is shown that the most studied and used in mass production materials for the manufacture of crystals operating in the temperature range up to 300-350 ºС and in some cases up to 500 ºС are silicon carbide of the 4H-SiC and 6H-SiC. The use of gallium nitride GaN as a material for crystals makes it possible to expand the operating temperature range of semiconductor devices to 600 ºС. These materials have a large band gap, a high charge carrier saturation rate, and a low concentration of intrinsic charge carriers. One of the main factors limiting the growth rate of production of high-temperature electronics products is the complexity of packaging. It is shown that special attention of researchers is currently paid to the selection of case materials, materials for fastening crystals and materials of conductors connecting the contact pad of the crystals with the traverses of the case and coordinating the coefficient of thermal expansion of the crystal, the material for fastening the crystal and the housing seat on which the crystal is placed.

The advantages and short circuit characteristics of SiC MOSFETs

SiC MOSFETs have exhibited considerable benefits in high-frequency, high-voltage, and high-temperature power electronics applications with outstanding material attributes as a result of the rapid advancement of power electronics technology. SiC MOSFETs slower short-circuit tolerance and faster switching rates provide new issues for the short-circuit prevention technology. In the opening section of the study, Si and SiC MOSFETs are compared and evaluated using various models and parametric factors. It has been demonstrated that SiC MOSFETs outperform Si MOSFETs in a variety of conditions and applications. The many SiC MOSFET short-circuit failure types as well as their underlying theories are initially explained in the papers main body. In addition, it examines the fundamentals of short-circuit test procedures and SiC MOSFET test circuits. The issues and limitations of the currently available SiC MOSFET short-circuit protection technology are then explored, along with factors impacting the short-circuit of SiC MOSFETs that are thoroughly examined. Lastly, the SiC MOSFET short-circuit protection technology development trend is forecasted, and potential future areas for improvement and innovation are considered. SiC MOSFET short-circuit protection technology will be enhanced and optimized to satisfy the needs of efficient and dependable power electronic systems as technology advances and application requirements expand.

Design and Fabrication of Piezoresistive Strain-Gauges for Harsh Environment Applications

Maximum operating temperature is usuallyone of the limiting factors for using of conventional sensors and other electronic devices. High-temperature sensors and electronics are required in some special applications e.g. measurement of deformations, stresses and pressures inside power generators. The design methodology of the some piezoresistive sensors utilizing FEM simulations is presented. Piezoresistive sensors based on thin-film metal sputtered layers, silicon-on-insulator (SOI) and nanocrystalline diamond layers (NCD) were successfully designed, fabricated and measured. The fabricated sensors are able to operate at temperatures up to 250 °C. Extensive study of sensor parameters e.g. deformation sensitivity, edge and contact resistances, temperature dependences gauge factor, bridge output voltage was performed. The measured values and investigated findings can be used for calibration of simulation software and in prospective design of more complex sensor structures.

β -rays induced displacement damage on epitaxial 4H-SiC revealed by exciton recombination

One of the most interesting wide-bandgap semiconductor is 4H-SiC that has an indirect wide-bandgap of 3.3 eV. This material holds great potential to develop power devices that find applications in the field of high-voltage and high-temperature electronics and harsh environments. In this study, we employed complementary noninvasive characterization techniques, including micro-Raman, optical absorption, steady-state, and time-resolved photoluminescence spectroscopy, to investigate the characteristics of a 12 μm thick epitaxial layer of 4H-SiC grown on 4H-SiC. Furthermore, we explored the impact of ionizing radiation on this material, utilizing β-rays and two x-ray sources. The doses are in the range of 1–100 kGy for electrons with energy of 2.5 MeV, 16 kGy for the first x-ray source (an x-ray tube with a W target operating at an anode bias voltage of 28 kV), and 100 kGy for the second x-ray source (an x-ray tube with a W target operating at an anode bias voltage of 100 kV). When exposed to the electron beam, the excitonic band at 3.2 eV exhibits a reduction in its lifetime as the deposited dose increases. In particular, in samples characterized by a greater amount of native defects, both extended and point defects, this effect becomes evident at lower deposited doses. Conversely, in the samples subjected to x-ray irradiation, these effects are not observed. These findings indicate that electron beam irradiation triggers the formation of defects associated with atomic displacement. Ultimately, we have examined the impact of thermal treatments in air, ranging from 100 to 900 °C, to investigate the recovery characteristics of 4H-SiC.

Low-temperature packaging through Ag-Cu supersaturated solid solution nanoparticle paste for high-temperature power electronics

In this work, anti-oxidative single-phase Ag-Cu supersaturated solid-solution nanoparticles (Ag-Cu SS-NPs) were synthesized by a one-step method to serve as packaging materials for high-temperature power electronics. After sintering at 250 ℃ in air, a dense supersaturated structure with nano-sized Cu precipitates and coherent twins, high shear strength over 133 MPa and low resistivity (4.35 μΩ·cm) were obtained. Notably, the supersaturated structure with nano-sized Cu precipitates enhanced the thermomechanical properties and high-temperature stability. The high-temperature shear strengths of the sintered Ag-Cu joints reached remarkable 93.5 MPa at 300 ℃. Meanwhile, the room-temperature shear strength of the sintered Ag-Cu SS-NP joints after aging at 300 ℃ for 500 h was maintained at 98.7 MPa, doubling that of the sintered Ag joints. Hence, the Ag-Cu SS-NP paste presents excellent feasibility and potential for high-temperature power electronics.

Heteroepitaxy of N-polar AlN on C-face 4H-SiC: Structural and optical properties

To date, it has remained challenging to achieve N-polar AlN, which is of great importance for high power, high frequency, and high temperature electronics, acoustic resonators and filters, ultraviolet (UV) optoelectronics, and integrated photonics. Here, we performed a detailed study of the molecular beam epitaxy and characterization of N-polar AlN on C-face 4H-SiC substrates. The N-polar AlN films grown under optimized conditions exhibit an atomically smooth surface and strong excitonic emission in the deep UV with luminescence efficiency exceeding 50% at room temperature. Detailed scanning transmission electron microscopy (STEM) studies suggest that most dislocations are terminated/annihilated within ∼200 nm AlN grown directly on the SiC substrate due to the relatively small (1%) lattice mismatch between AlN and SiC. The strain distribution of AlN is further analyzed by STEM and micro-Raman spectroscopy, and its impact on the temperature-dependent deep UV emission is elucidated.

GREEN CHEMISTRY FOR PROTECTION OF HIGH TEMPERATURE (> 250°C) ELECTRONICS

A new modified “green” thermoset resin was developed and evaluated as an alternative encapsulation packaging material in comparison to traditional higher temperature resistant resins such as epoxies, silicones, cyanate esters and polyimide resins. Where epoxies and silicones have shown to provide good reliability for applications up to 150 – 200°C, high temperature applications, often required other chemistries, such as cyanate ester or polyimides. However, cyanate ester and/or polyimide based resins have recently been affected by new European environmental legislation making their usability, and especially environmental and health acceptance, not viable for the medium and long term. In combination to these environmental concerns, the current significant growth of the market for high power and high temperature electronics, also in more “consumer-type” applications, imply the need for “green” chemistry, capable to respond to high temperature (> 250°C) requirements. This paper will describe new materials, based on hybrid chemistry, in line with current European chemical (SVHC-compliant) regulations, responding to the current and future harsh environment requirements. DSC analysis was done to demonstrate the newly developed green chemistry provides Tg values well over 250°C. The combination of a hybrid chemistry with optimized adhesion properties, high Tg and low coefficient of thermal expansion seem to provide mechanical features which can address the problem of mechanical fatigue of traditional epoxy solutions, which did historically not provide the solutions which often, non-environmental friendly solutions, based on poly-imides or cyanate esters could offer.

Pt/HTCC Alumina based Electronic Packaging System and Integration Processes for High Temperature Harsh Environment Applications

Electronic devices capable of operation at 500°C are required for long term Venus surface missions, as well as for in situ monitoring and control of next generation aeronautical engines. High temperature sensors and electronics can also find many applications in military, and energy and automobile industries. Various silicon carbide (SiC) sensors and electronic devices have been developed for operation at 500 °C, and a compatible packaging system is needed for long term test and deployment of these high temperature devices. High temperature co-fired ceramics (HTCC) alumina with platinum (Pt) conductor was proposed for high temperature electronic packaging. A prototype Pt/HTCC alumina packaging system including chip-level package and circuit board has been briefly reported previously for long-term electrical testing of SiC integrated circuits at 500 °C, and brief testing at much higher temperatures. HTCC alumina is an excellent dielectric material with acceptable dielectric constant and low dielectric loss over wide temperature and frequency ranges. Pt is chemically noble and can be co-fired with HTCC alumina in air ambient producing a viable electronic packaging material system for high temperature applications. This paper presents a more detailed description of this packaging system including prototype low power packages and circuit boards based on HTCC alumina and Pt metallization for 500°C and other harsh environment applications. The key technical considerations for chip-level packaging and circuit board assembly, including materials and processes for 500 °C durable wire-bonding and SiC die attach, and integration of multi-chip circuit boards, are presented. Experimental test results of this packaging approach applied to SiC integrated circuits at 500 °C and 700°C are discussed as well.

Bonding with brazing alloys as high-temperature interconnection filler through self-propagating exothermic reaction

There has been growing interest in wide bandgap (WBG) semiconductors including SiC and GaN due to the increasing demands for electronic devices serving at high temperatures. However, to maximise the potential capacity of WBG devices, new high-temperature interconnection materials and processes are indispensable as the current existing Sn-based solder alloys and bonding processes developed for Si devices are unable to meet the reliability requirements. In the present work, reactive brazing alloys including Cu-15Ag-5P and Incusil (Ag-27.25Cu-12.5In-1.25Ti) with melting points above 600°C have been utilized as the interconnection materials which offer excellent properties under high operation temperature. The self-propagating exothermic reaction (SPER) was applied for the bonding process via an intense rapid local heating and cooling at a millisecond scale. The strong Cu/Cu-15Ag-5P/Cu and Cu/Incusil/Cu sandwich bonded structures have been created with the assistance of SPER, where the nanofoil was applied from the outside of stacked structures as an external heat source and the bonding process was conducted in the ambient atmosphere without using flux. It has been found that the P element in Cu-15Ag-P alloy has the self-flux effect, which is beneficial for the ultra-fast interfacial reaction process. The experiments where the nanofoil was placed inside of stacked structures between two sheets of brazing alloys have also been conducted, which exhibited the well-bonded interface microstructures between nanofoil and brazing alloys. The outlook on the design for practicality and industrial uses for SPER-assisted bonding with brazing alloys has also been discussed, as a potential viable assembly route for the high-temperature and high-power electronics packaging.

Prototyping Na0.5Bi0.5TiO3-based multilayer ceramic capacitors for high-temperature and power electronics

Prototyping Na0.5Bi0.5TiO3-based multilayer ceramic capacitors for high-temperature and power electronics

High Temperature Inertial Navigation Sensors, Electronics and Packaging for reliable 300°C Operation

Conventional oil and gas drilling measurement while drilling (MWD) systems are typically designed to operate at temperatures <200°C. To increase the efficiency of drilling unconventional geothermal wells, downhole MWD tools are needed that can operate in the unique thermal challenges encountered in enhanced geothermal systems (EGS). GE demonstrated a 300°C downhole navigation system. The system utilizes GE’s internally developed state-of-the-art MEMS multiple ring Gyroscope (MRG), and a high temperature gyroscope control and readout application specific integrated circuit (ASIC). The MRG, ASIC and associated high temperature, high reliability packaging were integrated to demonstrate the performance and functionality of the gyroscope across the temperature range from room temperature to 300°C. Specialized long-term capable high temperature test platforms were developed to enable the characterization and testing of the gyroscope system and utilized to validate application-relevant lifetime capability.

Additive Manufacturing of High‐Temperature Hybrid Electronics via Molecular‐Decomposed Metals

AbstractAs the modern electronic technology extends into operating in harsh working conditions, it calls for a system that is capable of uncompromising performance in extreme environments, thus providing a strong motivation to look for advanced materials and electronics with the capability of high‐throughput and rapid prototyping. Coupled with additive manufacturing, molecular decomposition metals bypass the challenging oddities of traditional material‐limited and thermally initiated metalworking, enabling high throughput and rapid prototyping of stoichiometry and composition‐controlled metals. Here, a new paradigm for the design and additive manufacturing of copper metallic alloy materials onto ceramics is described by printing molecular decomposable metal materials, capable of withstanding thermo‐mechanical loading, operating in extreme environments in static and dynamic conditions. The resulting printed hybrid electronics are electrically stable for 25 h of aging at 1000 °C. This curious fact paves a way for printed antenna and sensor electronics that reliably operate up to 1000 °C. These results can be further extended to establish other printable molecular decomposable materials as a platform for rapid prototyping of high temperature electronics that are suitable for harsh environments.

High-Temperature Electronics Enabled by Copper–Platinum and Polymer-Derived Silicon Oxycarbide through Additive Manufacturing

High-Temperature Electronics Enabled by Copper–Platinum and Polymer-Derived Silicon Oxycarbide through Additive Manufacturing

Temperature and field dependencies of current leakage mechanisms in IrOx contacts on InAlN/GaN heterostructures

This Letter reports on the mechanisms of reverse leakage current transport in InAlN/GaN heterostructure Schottky diodes with intentionally oxidized iridium oxide (IrOx) contacts across a wide temperature range. Current–voltage characteristics were experimentally measured from 25 to 500 °C (≈ 300 to 773 K). Three distinct regions in the reverse bias regime of operation and their corresponding dominant current transport mechanisms are identified. A trap-assisted tunneling mechanism is observed at low reverse bias, and trap energy levels are between 1.12 and 1.99 eV. At medium reverse bias, Poole–Frenkel emission is decomposed into low-field, mid-field, and high-field regions and the related trap activation energies vary from 0.38 to 2.04 eV. At high reverse bias, the Fowler–Nordheim model is applied and the effective barrier height to tunneling is 0.78 eV. The model of the reverse leakage current constructed using the parameters associated with these transport mechanisms closely aligns with the experimental data and supports the advancement of high-temperature electronics based on IrOx -gated InAlN/GaN heterostructure technology.

Polyarylene ether nitrile dielectric films modified by HNTs@PDA hybrids for high-temperature resistant organic electronics field

Abstract In this work, mussel-inspired surface functionalization of halloysite nanotubes (HNTs) were coated by in situ self-polymerization of polydopamine (PDA) to synthesize core-shell structural composites (HNTs@PDA), and then incorporated into polyarylene ether nitrile (PEN) matrix. Due to the strong adhesion of the PDA modification layer and the formation of hydrogen bonds between the polar nitrile group of PEN and the catechol group of PDA, the dispersion and interfacial compatibility of HNTs@PDA in the PEN matrix are improved. The results show that the dielectric constant of PEN/HNTs@PDA 20 nanocomposites reaches 11.56 (1 kHz), which is 3.2 times that of pure PEN. In addition, after heat treatment, a chemical cross-linking reaction occurred between the PEN matrix to form a cross-linked PEN (CPEN) based nanocomposites, which further improved the thermal stability of the nanocomposites. The results show that the T g of CPEN/HNTs@PDA 20 nanocomposites reaches 215.5°C, which is 47.7°C higher than that of PEN/HNTs@PDA 20. Moreover, the dielectric constant-temperature coefficient of all CPEN nanocomposites is less than 7 × 10−4°C−1 at the temperature range of 25–180°C. All in all, this work provides a simple and environmentally friendly strategy to adjust the dielectric properties of polymer-based ceramic nanocomposites, which provides a pathway for its application as a dielectric material in the film capacitors field.