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[IEEE 2018 19th International Conference on Electronic Packaging Technology (ICEPT) - Shanghai (2018.8.8-2018.8.11)] 2018 19th International Conference on Electronic Packaging Technology (ICEPT) - Effect of Ni thickness on the IMC and reliability of ultrathin ENEPIG
摘要： Electroless Ni(P)/electroless Pd/immersion Au （ ENEPIG ） is a common surface finish featured by good solderability, wide application and reliable mechanical properties. With the miniaturization and high integration of the integrated circuits, high thickness of Ni-P will affect the signal integrity because of the gigantic resistance. This study focused on the effect of the Ni layer thickness on the morphology and evolution of IMC and the reliability of ENEPIG. Commercial SAC305 solders were reflowed on different thicknesses of Ni (0.3um and 3um) to study the Cu/Ni IMC evolution while OSP sample was used as a control sample. Aged experiments were conducted at 150°C to evaluate the long term thermal stabilization and After every aging stage, we conducted high speed shear test to estimate the mechanical strength of the IMCs and analysis of fracture morphology. After aging, scallop-shaped IMCs of (Cu,Ni)6Sn5 was formed and its thickness increased with aging as well. Brittle IMC (Cu,Ni)3Sn first began to appear in ultrathin ENEPIG and the shear strength dropped slightly. After 256 h aging, ultrathin Ni layer had been completely consumed and a large number of (Cu,Ni)3Sn formed while 5um ENEPIG still had a good barrier effect. Even if Ni layer had been consumed, ultrathin ENEPIG still had a certain inhibitory effect on IMC growth compared with OSP, probably because of the formation of NiSnP layer. Further drop tests and temperature cycle tests will be conducted and the failure models together with cause will be also presented combined with previous results of IMC evolution.
关键词： ENEPIG,Ni thickness,Reliability,Ultrathin,IMC
更新于2025-09-23 15:19:57
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Flexible transnasal endoscopy with white light or narrow band imaging for the diagnosis of laryngeal malignancy: diagnostic value, observer variability and influence of previous laryngeal surgery
摘要： Purpose Flexible transnasal endoscopy is a common examination technique for the evaluation of laryngeal lesions, while the use of narrow band imaging (NBI) has been reported to enhance the diagnostic value of white light endoscopy (WLE). The purpose of this study is to assess observer variability and diagnostic value of both modalities and investigate the possible influence of previous laryngeal surgery on the detection rates of laryngeal malignancy. Methods The study was based on the retrospective evaluation of 170 WLE and NBI images of laryngeal lesions by three observers in a random order. The histopathological diagnoses serve as the gold standard. Results In identifying laryngeal malignancy, the sensitivity of NBI proved to be higher than that of WLE (93.3% vs. 77.0%). NBI was also superior to WLE in terms of accuracy (96.3% vs. 92%) and diagnostic odds ratio (501.83 vs. 120.65). Both modalities had a specificity of 97.3%. The inter-observer agreement was substantial (kappa = 0.661) for WLE and almost perfect (kappa = 0.849) for NBI. Both WLE and NBI showed a high level of intra-observer agreement. The sensitivity was significantly lower in images with history of previous laryngeal surgery compared to those without. Conclusions Flexible transnasal endoscopy has been proved to be a valuable tool in the diagnosis of laryngeal malignancy. The use of NBI can increase the sensitivity and observer reliability in that context and can also provide a diagnostic gain in cases with previous laryngeal surgery
关键词： Observer reliability,Narrow band imaging,Laryngeal endoscopy,Laryngeal cancer
更新于2025-09-23 15:19:57
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Benefits of Considering More than Temperature Acceleration for GaN HEMT Life Testing
摘要： The purpose of this work was to investigate the validity of Arrhenius accelerated-life testing when applied to gallium nitride (GaN) high electron mobility transistors (HEMT) lifetime assessments, where the standard assumption is that only critical stressor is temperature, which is derived from operating power, device channel-case, thermal resistance, and baseplate temperature. We found that power or temperature alone could not explain difference in observed degradation, and that accelerated life tests employed by industry can bene?t by considering the impact of accelerating factors besides temperature. Speci?cally, we found that the voltage used to reach a desired power dissipation is important, and also that temperature acceleration alone or voltage alone (without much power dissipation) is insuf?cient to assess lifetime at operating conditions.
关键词： lifetime testing,device degradation,HEMT,gallium nitride,reliability
更新于2025-09-23 15:19:57
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Fabrication of Two-Dimensional Crystalline Organic Films by Tilted Spin Coating for High-Performance Organic Field-Effect Transistors
摘要： We developed a facile method for fabricating large-area two-dimensional (2D) organic highly crystalline films and extended it to organic thin-film transistor arrays. Tilted spinning provided oriented flow at the three-phase contact line and 2D crystalline film that consisted of layer-by-layer stacked 2,7-diocty[1]benzothieno[3,2-b]benzothiophene (C8-BTBT) was obtained facilely for organic thin-film transistor (OTFT). The extracted field-effect mobility is 4.6 cm-2 V-1 s-1 but with non-ideal features. By applying this method to microdroplet arrays, oriented crystal was fabricated, and the channel region for OTFTs was covered by adjusting the spinning speed. By tuning the tilt angle (θ) of the revolving substrate, we fabricated high-performance OTFT arrays with average and maximum mobilities of 7.5 and 10.1 cm-2 V-1 s-1, respectively, that exhibited high reliability factors of over 90 % and were closed to ideal transistors. These results suggest that high-quality crystalline film can be obtained via a facile tilted spinning method.
关键词： oriented flow,reliability factor,tilted spin coating,two-dimensional,highly crystalline film
更新于2025-09-19 17:15:36
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Gate Reliability of p-GaN gate AlGaN/GaN High Electron Mobility Transistors
摘要： The gate reliability of p-GaN gate AlGaN/GaN high electron mobility transistors with a ring-gate structure is investigated by step-stress experiments under gate bias, combined with electroluminescence imaging and pulsed measurements. For gate stress (VGstress) from 0 V to 13 V, drain current is found to be stable and decreased at 13 V at off-state and increased at on-state. For VGstress from 13 V to 31 V, drain current increases at off-state and decreases at on-state, whereas VTH is stable and increases slightly. The changes in drain current characteristic and VTH of the device after applying various VGstress are associated with the injection and trapping of holes from the p-GaN layer to the AlGaN layer, supported by the results of pulsed measurements and by the simulation of energy band diagrams. When VGstress is further increased to a high voltage of 31 V, VTH becomes noisy and a strong luminescence signal occurs with a sudden reduction in drain current, and finally, a catastrophic failure happens in the gate-channel region.
关键词： AlGaN/GaN,HEMTs,reliability
更新于2025-09-19 17:15:36
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Reliability of rare-earth-doped infrared luminescent nanothermometers
摘要： The use of infrared-emitting rare-earth-doped luminescent nanoparticles as nanothermometers has attracted great attention during the last few years. The scientific community has identified rare-earth-doped luminescent nanoparticles as one of the most sensitive and versatile systems for contactless local temperature sensing in a great variety of fields, but especially in nanomedicine. Researchers are nowadays focused on the design and development of multifunctional nanothermometers with new spectral operation ranges, outstanding brightness, and enhanced sensitivities. However, no attention has been paid to the assessment of the actual reliability of the measurements provided by rare-earth-doped luminescent nanothermometers. In fact, it is assumed that they are ideal temperature sensors. Nevertheless, this is far from being true. In this work we demonstrate that the emission spectra of rare-earth-doped nanothermometers can be affected by numerous environmental and experimental factors. These include the numerical aperture of the optical elements used for their optical excitation and luminescence collection, the local concentration of nanothermometers, optical length variations, self-absorption of the luminescence by the nanothermometers themselves, and solvent optical absorption. This work concludes that rare-earth-doped luminescent nanothermometers are not as reliable as thought and, consequently, special care has to be taken when extracting temperature estimations from the variation of their emission spectra.
关键词： reliability,solvent absorption,self-absorption,excitation power dependence,infrared luminescent nanothermometers,rare-earth-doped
更新于2025-09-19 17:15:36
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[IEEE 2019 IEEE 8th International Conference on Advanced Optoelectronics and Lasers (CAOL) - Sozopol, Bulgaria (2019.9.6-2019.9.8)] 2019 IEEE 8th International Conference on Advanced Optoelectronics and Lasers (CAOL) - Computed tomography dataset analysis for stereotaxic neurosurgery navigation
摘要： First-ever 28 nm embedded split-gate MONOS (SG-MONOS) ?ash macros have been developed to increase memory capacity embedded in micro controller units and to improve performance over wide junction temperature range from C to 170 C as demanded strongly in automotive uses. Much attention has been paid to the degradation of the reliability characteristics along with the process shrinkage. Temperature-adjusted word-line overdrive scheme improves random read access frequency by 15% and realizes both of 6.4 GB/s read throughput by 200 MHz no-wait random access of code ?ash macros and more than ten times longer TDDB lifetime of WL drivers. Temperature-adaptive step pulse erase control (TASPEC) improves the TDDB lifetime of dielectric ?lms between metal interconnect layers by three times. TASPEC is particularly useful for a data ?ash macro with one million rewrite cycles. Source-side injection (SSI) program with negative back-bias voltage achieves 63% reduction of program pulse time and, consequently, realizes 2.0 MB/s write throughput of code ?ash macros. A spread spectrum clock generation and a clock phase shift technique are introduced for charge pump clock generation in order to suppress EMI noise due to high write throughput of code ?ash macros, and peak power of EMI noise is reduced by 19 dB.
关键词： high-temperature operation,time dependent dielectric breakdown,Automotive application,high reliability,spread spectrum clock generation,word-line over-drive,split-gate MONOS(SG-MONOS),embedded ?ash memory,Fast random read operation
更新于2025-09-19 17:13:59
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[IEEE 2019 Workshop on Recent Advances in Photonics (WRAP) - Guwahati, India (2019.12.13-2019.12.14)] 2019 Workshop on Recent Advances in Photonics (WRAP) - Shadowgraphic Imaging of Cavitation Bubble Dynamics in Pulsed Laser Ablation of a Solid in Liquid
摘要： Insulated-gate bipolar transistor (IGBT) power modules find widespread use in numerous power conversion applications where their reliability is of significant concern. Standard IGBT modules are fabricated for general-purpose applications while little has been designed for bespoke applications. However, conventional design of IGBTs can be improved by the multiobjective optimization technique. This paper proposes a novel design method to consider die-attachment solder failures induced by short power cycling and baseplate solder fatigue induced by the thermal cycling which are among major failure mechanisms of IGBTs. Thermal resistance is calculated analytically and the plastic work design is obtained with a high-fidelity finite-element model, which has been validated experimentally. The objective of minimizing the plastic work and constrain functions is formulated by the surrogate model. The nondominated sorting genetic algorithm-II is used to search for the Pareto-optimal solutions and the best design. The result of this combination generates an effective approach to optimize the physical structure of power electronic modules, taking account of historical environmental and operational conditions in the field.
关键词： fatigue,power cycling (PC),insulated-gate bipolar transistors (IGBTs),thermal cycling (TC),reliability,optimization methods,finite-element (FE) methods,Aging,multiobjective
更新于2025-09-19 17:13:59
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Degradation mechanisms of bias stress on nitride-based near-ultraviolet light-emitting diodes in salt water vapor ambient
摘要： Degradation mechanisms of nitride-based near-ultraviolet (near-UV) light-emitting diodes (LEDs) were systematically analyzed by applying forward- and reverse-bias stresses to them in a salt water vapor ambient. The surface temperature of the forward-bias stress sample was higher than that of the reverse-bias stress sample. The high temperature of the forward-bias stress sample accelerated the chemical reaction of the device structure with salt water vapors and led to faster degradation. Composition analyses of the sample surface and cross-section were conducted to investigate the failure mechanism. The analyses results indicated that the erosion of the indium–tin–oxide layer enhanced the diffusion of the conducting metal into the LED crystal. The proposed method can effectively characterize the quality of near-UV LEDs in a short duration.
关键词： failure mechanisms,bias stress,reliability,near-UV LEDs
更新于2025-09-19 17:13:59
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Accurate Sizing of Residential Stand-Alone Photovoltaic Systems Considering System Reliability
摘要： In rural areas or in isolated communities in developing countries it is increasingly common to install micro-renewable sources, such as photovoltaic (PV) systems, by residential consumers without access to the utility distribution network. The reliability of the supply provided by these stand-alone generators is a key issue when designing the PV system. The proper system sizing for a minimum level of reliability avoids unacceptable continuity of supply (undersized system) and unnecessary costs (oversized system). This paper presents a method for the accurate sizing of stand-alone photovoltaic (SAPV) residential generation systems for a pre-established reliability level. The proposed method is based on the application of a sequential random Monte Carlo simulation to the system model. Uncertainties of solar radiation, energy demand, and component failures are simultaneously considered. The results of the case study facilitate the sizing of the main energy elements (solar panels and battery) depending on the required level of reliability, taking into account the uncertainties that affect this type of facility. The analysis carried out demonstrates that deterministic designs of SAPV systems based on average demand and radiation values or the average number of consecutive cloudy days can lead to inadequate levels of continuity of supply.
关键词： photovoltaic generation,battery storage,renewable energy,Monte Carlo Simulation,reliability evaluation
更新于2025-09-19 17:13:59