Devices For Automotive Applications Research Articles

Impact of neutron irradiation on SiC power MOSFETs after stress tests qualification

The failure of power devices produced by atmospheric neutrons, even at sea level, is a critical issue to assess the reliability of these devices in automotive applications. Usually, accelerated neutron tests are performed to estimate the failure in time (FIT) values of the power devices under different operating conditions, by using virgin device samples. In this work, neutron tests were performed on commercial SiC power MOSFETs which pass HTGB and HTRB qualification tests, commonly used in automotive qualification procedures to verify the gate-oxide and junction and termination integrity. The impact of these reliability qualification tests on the neutron FIT values was investigated.

Enhancement of Board Level Reliability on Automotive DRAM Package by Optimized Thermal & Mechanical Properties

Abstract As increased in demand for using memory devices in automotive applications, board level reliability (BLR) has been the one of the critical issue for using FBGA type packages in automotive. The required specification of BLR is listed in various standards (AEC-Q100, Q104 etc) and it is varied by automotive application customers. Most of customers are targeting grade from 1 to 3, however, requirement to memory package is grade 1 (−40°C~125°C). Currently low power (LP) memory device is widely adopted in automotive applications due to its wide bandwidth and high density capability. From package reliability point of view, it is challenge to satisfy the required BLR for target package by 1) dimension optimization, 2) selection of material, 3) mount condition, and 4) work around method. In this paper, the best combination to achieve the highest BLR life time was investigated compared with current mobile application LP4 package. Large pad size with large ball, high content of Ag in solder ball and Ni/Au pad finish were the best combination to result in the longest life time. Various density of LP4 package BLR were also estimated by mechanical simulation based from actual thermal cycling test on the highest Si volume LP4 package.

Multimirror Array Optics for Augmented Reality Devices in Automotive Applications

This paper is an overview of multimirror array (MMA) optics for augmented reality (AR) devices. MMA optics is compact optics for constructing augmented reality devices. We made a prototype wearable display with MMA optics. By using MMA, the appearance of our wearable display is like a typical eyeglasses. We also made a prototype wide field of view combiners for head-up displays (HUD) with a Fresnel reflector. In addition, we developed optical distortion correction for projecting the images on MMA. Projected images are undistorted, thus ghost images are eliminated.

Thermal Management and Characterization of High-Power Wide-Bandgap Semiconductor Electronic and Photonic Devices in Automotive Applications

GaN-based high-power wide-bandgap semiconductor electronics and photonics have been considered as promising candidates to replace conventional devices for automotive applications due to high energy conversion efficiency, ruggedness, and superior transient performance. However, performance and reliability are detrimentally impacted by significant heat generation in the device active area. Therefore, thermal management plays a critical role in the development of GaN-based high-power electronic and photonic devices. This paper presents a comprehensive review of the thermal management strategies for GaN-based lateral power/RF transistors and light-emitting diodes (LEDs) reported by researchers in both industry and academia. The review is divided into three parts: (1) a survey of thermal metrology techniques, including infrared thermography, Raman thermometry, and thermoreflectance thermal imaging, that have been applied to study GaN electronics and photonics; (2) practical thermal management solutions for GaN power electronics; and (3) packaging techniques and cooling systems for GaN LEDs used in automotive lighting applications.

Impact of electromagnetic interference on the functional safety of smart power devices for automotive applications

Integrated smart power devices gain more and more importance in the field of automotive systems. In addition to power transistors such devices usually contain several integrated diagnostic and protection functions. In the event of a fault these functions enable the connected control unit to react appropriately and to protect the application and thus the people. Smart power devices are often responsible for important tasks within a vehicle and are nowadays more and more used to substitute conventional elements like fuses, relays and switches. During the operation they are often exposed to harsh environmental conditions such as high operating temperatures, mechanical stress, etc. At the same time different electromagnetic interferences (EMI) may occur, which can affect their normal functionality. Especially in safety-critical applications such as the airbag control module or the Anti-lock Braking System their correct function is very important to avoid dangerous operating conditions and to ensure functional safety. Based on EMI investigations on a representative smart power high side switch it is shown in this paper to what degree of electromagnetic interference smart power devices are still able to correctly detect critical fault conditions and remain in their fail-save state.

두께와 열전소자 부착위치를 고려한 자동차용 고효율 전자 냉온 모듈 형상 최적화 연구

The demand for user convenient devices in automotive applications are fast growing, mainly driven by the customer's requirement for higher efficiency and more features. In important such feature is the cold module for cars, which are convenient luxuries that warm or cool drinks placed in the cup holder by means of a thermoelectric element. In present study, we would like to find out the optimal thickness of the cup holder and mounting position of the thermoelectric element through experiments under various testing conditions and thermal analysis. The resulting thermal distribution of the primary area of thermal analysis was found to be lowest when the thickness was 2.5 mm. The temperature distribution was also lowest when the thermal element was positioned underneath the holder (A-type).

Development of high-efficiency and high-power vertical light emitting diodes

We provide an overview of the vertical chip technology and discuss recent improvements that have enabled (AlGaIn)N-based light-emitting diodes to further extend the range of their applications. In particular, the excellent scalability of chip size and low electric losses make related devices predestinated for use in high-power and high-luminance tasks. The evolution from standard vertical chips to the advanced chip design is described from a conceptual as well as from a performance point of view. Excellent stability data under demanding conditions are shown, which are the basis for the operation of devices in automotive applications requiring high reliability at current densities exceeding 3 A/mm2. As the vertical chip technology is not directly dependent on the substrate owing to its removal in the chip process, it is highly flexible with respect to the change of substrate materials to the very promising (111) silicon, for example.

Intercalated Metal-Organic Framework Electrode Materials for High-Voltage Stacked Batteries

The research and development of rechargeable batteries is of particular importance because of their promise as large-scale energy storage devices in automotive applications and stationary power-storage systems. By stacking multiple positive and negative electrode pairs described as bipolar electrodes within a single cell, design of more powerful and useful stacked rechargeable batteries for the large-scale applications is possible. While Al and Cu are typically used as current collectors for positive and negative electrodes, respectively, the bipolar electrodes for the proposed battery use a single Al foil coated with both positive and negative electrode materials. When designing a stacked cell with bipolar electrodes based on Al current collectors, unfortunately, conventional negative electrode material of graphite carbon cannot be used because Al reacts with Li at a potential (0.4 V (vs. Li/Li+)) higher than that of the Li intercalation of graphite (0.1). When t lithium titanate spinel (Li4Ti5O12) operating at a potential of 1.55 V is used, on the other hand, the cell voltage becomes considerably low and total energy density decreases drastically as a result. Therefore, reversible Li intercalation materials which operate from 0.5 to 1.0 V are essential for the negative electrode. So, we focus on redox systems of π-conjugated dicarboxylate materials 1,2 and found that some of the π-conjugated dicarboxylate materials had a characteristic molecular self-assembly which provided reversibility. In the presentation, we introduce the intercalated metal-organic framework (iMOF), 2,6-naphthalene dicarboxylate dilithium (2,6-Naph(COOLi)2) as the target negative electrode material (Fig. 1).3, 4 This material has repeating organic and inorganic units comprising π-stacked naphthalene packing and tetrahedral LiO4 units. The naphthalene units interact with each other through π-stacking interactions. The Li atoms form slightly distorted LiO4 tetrahedral structures, which are connected by an extensive network of one edge-sharing and two corner-sharing tetrahedral LiO4units that are framed by four O atoms of different naphthalene dicarboxylate units. Hence, such molecular self-assembly ensures high structural stability.The 2,6-Naph(COOLi)2 electrode shows a reversible two-electron-transfer reaction (230 mAh g–1 per active material) at a flat potential plateau of 0.8 V with narrow polarization in in LiPF6/EC+DMC+EMC. This material exhibits an intercalation reaction of Li into the tetrahedral LiO4 layer by redox systems of the π-stacked naphthalene packing layer. Its volumetric change was ca. 10 % while the framework remains constant during charging and discharging. This value is approximately the same volumetric change as that observed for graphite carbons. Intercalated Li+ is stabilized as a tetrahedral LiO3C structure composed of three O atoms of different dicarboxylate units and naphthalene C atom covalently-bonded carboxylate groups indicating Li+transport channel. The organic-inorganic interlayer distance remains constant while π-stacking interaction for naphthalene packing slightly increases, which contributes to electron-transfer channel. Such molecular self-assembly having two-dimensional pathways for efficient electron and ion transports provides the observed electrochemical reversibility.As a preliminary step for the high-voltage stacked Li-ion batteries, a 4-V Li-ion cell was fabricated with 2,6-Naph(COOLi)2 negative and high potential-operating LiNi0.5Mn1.5O4spinel positive electrodes in the available potential range of the Al current collector. The resulting charge–discharge profile reveals a cell voltage of 3.9 V (Fig. 2) and the same reproducible reversible capacity. In addition, the operating potential of the negative electrode is expected to suppress the deposition of metallic Li (0 V). Thus, our results show that the use of iMOFs will aid in designing high-energy-density batteries with improved safety.ReferencesM. Armand, S. Grugeon, H. Vezin, S. Laruelle, P. Ribière, P. Poizot, J.-M. Tarascon, Nature Mater. 8, 120 (2009).W. Walker, S. Grugeon, H. Vezin, S. Laruelle, M. Armand, F. Wudl, J.-M. Tarascon, J. Mater. Chem. 21, 1615 (2011)N. Ogihara. Japanese Patent, JP2011-074054.N. Ogihara. PTC Patent, WO2012-053553.

Quality assurance in automotive electronics

The qualification of semiconductor devices for automotive applications is based on a qualification procedure described in the AEC-Q100 and Q101 which are internationally accepted standards. As the requirements regarding reliability, lifetime and application conditions for automotive electronics are increasing dramatically this qualification method is not sufficient anymore to release the devices for the application in the car. In the following article new concepts for qualification and safe launch measures will be described. With the data resulting from a feasibility study for a new semiconductor package at Infineon Technologies the importance of extended stress tests beyond the AEC-Q100 will be shown.

Lifetime prediction and design of reliability tests for high-power devices in automotive applications

Different procedures are defined and compared to extract the statistical distribution of the thermal cycles experienced by power devices that are installed in hybrid vehicles and operated according to arbitrary mission profiles. This enables both to design efficient accelerated tests tailored on realistic data and to provide the input for lifetime prediction models. Initially, the system lifetime is predicted under the assumption of linear accumulation of the damage produced by low cycling fatigue. Also, a novel prediction model based on some fundamental equations is introduced which takes into consideration the creep experienced by compliant materials when they are submitted to thermal cycles.