Bond Wire Damage Detection Method on Discrete MOSFETs Based on Two-Port Network Measurement

Bond wire damage is one of the most common failure modes of metal-oxide semiconductor field-effect transistor (MOSFET) power devices in wire-welded packaging. This paper proposes a novel bond wire damage detection approach based on two-port network measurement by identifying the MOSFET source parasitic inductance (LS). Numerical calculation shows that the number of bond wire liftoffs will change the LS, which can be used as an effective bond wire damage precursor. Considering a power MOSFET as a two-port network, LS is accurately extracted from frequency domain impedance (Z−parameter) using a vector network analyzer under zero biasing conditions. Bond wire cutoff experiments are employed to validate the proposed approach for bond wire damage detection. The result shows that LS increases with the rising severity of bond wire faults, and even the slight fault shows a high sensitivity, which can be effectively used to quantify the number of bond wire liftoffs of discrete MOSFETs. Meanwhile, the source parasitic resistance (RS) extracted from the proposed two-port network measurement can be used for the bond wire damage detection of high switching frequency silicon carbide MOSFETs. This approach offers an effective quality screening technology for discrete MOSFETs without power on treatment.Electronic Components, Technology and Material

Inactivation of Escherichia coli and Staphylococcus aureus by using a UVC-LED module with a multi-wavelength setting

UVC-LED is known as a deep ultraviolet LED. The application development and disinfection efficiency of UVC-LED modules are important problems encountered when UVC-LED products are rushed into commercialization. In this article, a specific disinfection experiment with a UVC-LED module was combined to analyze the disinfection efficiency. UVC-LEDs with wavelengths of 260 and 280 nm were used and supplemented with UVA-LEDs with wavelengths of 360 and 390 nm. The module was packaged to investigate the inactivation of Escherichia coli and Staphylococcus aureus. Two new findings were obtained through the analysis and comparison of the experiments. First, the short wavelength from UVA might have an enhanced destructive effect on microorganisms when the radiation intensity of UVA-LED was sufficient with coupling UVA and UVC. Second, 260 nm UVC-LED lamp beads might have a shorter response time to inactivate microorganisms than 280 nm UVC-LED lamp beads. Bactericidal experiments near the surface and different radiation distances showed that the inactivation rate reached 99.9% after 1 min of exposure when the UVC-LED module was set at 260 or 280 nm wavelength lamp beads for disinfection. The disinfection efficiency of 280 nm UVC-LED lamp beads was higher than that of 260 nm UVC-LED lamp beads because of the increased UV intensity. The radiation distance was within 7.5 cm range, the exposure time was 60 s, the inactivation rate was over 99.9%, and the disinfection effect was remarkable. For current UVC-LED applications, such as near-surface UVC-LED, disinfection and air purification products have a high value.Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Electronic Components, Technology and Material

The effects of graphene stacking on the performance of methane sensor: A first-principles study on the adsorption, band gap and doping of graphene

The effects of graphene stacking are investigated by comparing the results of methane adsorption energy, electronic performance, and the doping feasibility of five dopants (i.e., B, N, Al, Si, and P) via first-principles theory. Both zigzag and armchair graphenes are considered. It is found that the zigzag graphene with Bernal stacking has the largest adsorption energy on methane, while the armchair graphene with Order stacking is opposite. In addition, both the Order and Bernal stacked graphenes possess a positive linear relationship between adsorption energy and layer number. Furthermore, they always have larger adsorption energy in zigzag graphene. For electronic properties, the results show that the stacking effects on band gap are significant, but it does not cause big changes to band structure and density of states. In the comparison of distance, the average interlamellar spacing of the Order stacked graphene is the largest. Moreover, the adsorption effect is the result of the interactions between graphene and methane combined with the change of graphene’s structure. Lastly, the armchair graphene with Order stacking possesses the lowest formation energy in these five dopants. It could be the best choice for doping to improve the methane adsorption.Electronic Components, Technology and Material

Failure quantitative assessment approach to MOSFET power device by detecting parasitic parameters

With the emerging wide bandgap (WBG) semiconductor development, the increasing power density and efficiency of power electronic converters may cause more switching oscillation, electromagnetic interference noise, and additional power loss, further increasing the probability of device failure. Therefore, determining and quantifying the failure of a metal-oxide-semiconductor-field-effect transistor (MOSFET), which assembled using WBG semiconductor in some applications, is crucial to improving the reliability of a power converter. This study proposes a novel failure quantitative assessment approach based on MOSFET parasitic parameters. According to the two-port network theory, MOSFET is equivalent to some second-order RLC circuits composed of independent inductances, capacitances, and resistances in series. Then, the frequency-domain impedance associated with the physical failure of MOSFET is identified through frequency domain reflectometry. Accelerated aging and bond wires cut-off experiments are employed to obtain various quality states of the MOSFET device. Result shows that the MOSFET quality level and its number of bond wire lift-offs can be quantified effectively. Drain-to-source on-resistance (RDS(on)) that normally represents the MOSFET quality shows a positive linear function relationship on drain-to-source parasitic resistance (RD + RS) during the quality degradation proceeding. This finding matches with the correlation established between RDS (on) and RD + RS in theory. Meanwhile, source parasitic inductance (LS) increases with the severity of bond wires faults, and even the slight fault shows a high sensitivity. The proposed approach would be an effective quality screening technology for power semiconductor devices without power on treatment, which can effectively avoid the impact of junction temperature and test conditions (current and voltage) on test results, and does not need to design additional test circuits. The test frequency range we used in this approach was 10–300 MHz, which to some extent is suitable for providing an on-line quality monitoring technology for high-frequency WBG power devices manufacturing.Electronic Components, Technology and Material

Color Shift Modeling of Light-Emitting Diode Lamps in Step-Loaded Stress Testing

The color coordinate shift of light-emitting diode (LED) lamps is investigated by running three stress-loaded testing methods, namely step-up stress accelerated degradation testing, step-down stress accelerated degradation testing, and constant stress accelerated degradation testing. A power model is proposed as the statistical model of the color shift (CS) process of LED products. Consequently, a CS mechanism constant is obtained for detecting the consistency of CS mechanisms among various stress-loaded conditions. A statistical procedure with the proposed power model is then derived for the CS paths of LED lamps in step-loaded stress testing. Two types of commercial LED lamps with different capabilities of heat dissipation (CHDs) are investigated. Results show that the color coordinates of lamps are easily modified in various stress-loaded conditions, and different CHDs of lamps may play a crucial role in the various CS processes. Furthermore, the proposed statistic power model is adequate for the CS process of LED lamps. The consistency of CS mechanisms in step-loaded stress testing can also be detected effectively by applying the proposed statistic procedure with the power model. Moreover, the constant assumption in the model is useful for judging the consistency of CS mechanisms under various stress-loaded conditions.Electronic Components, Technology and Material

Effects of Thermal Reflowing Stress on Mechanical Properties of Novel SMT-SREKs

A novel silicone rubber elastic key (SREK) is proposed in this paper for surface mounting technology (SMT) applications. Effects of thermal reflowing stress on the mechanical properties of SMT-SREKs are investigated. The manufactured SMT-SREKs, which underwent various reflowing conditions in advance, are subjected to pressing force and fatigue pressing tests. Fatigue lifetime projection model and its predicted error are then assessed systematically. The thermal degradation of silicone rubber materials is illustrated through the dynamic mechanical analysis and the Fourier transform infrared spectroscopy experiments. The mechanical finite element modeling is also conducted to simulate the pressing process. The results show that the pressing force and tactility of the SMT-SREKs are strongly affected by the reflowing condition, which contributes to the degradation of the silicone rubber materials. During the fatigue pressing test, the change rate of tactility increases with the reflowing peak temperature ( T-{p} ) and is accelerated by the repeated reflowing process. Moreover, a linear model can precisely project the tactility before the fatigue pressing number of 2.0E+6 times, and the impact rate of T-{p} on tactility with the increasing fatigue pressing number can be predicted effectively by using a logarithm model.Electronic Components, Technology and Material

Entropy generation methodology for defect analysis of electronic and mechanical components-A review

Understanding the defect characterization of electronic and mechanical components is a crucial step in diagnosing component lifetime. Technologies for determining reliability, such as thermal modeling, cohesion modeling, statistical distribution, and entropy generation analysis, have been developed widely. Defect analysis based on the irreversibility entropy generation methodology is favorable for electronic and mechanical components because the second law of thermodynamics plays a unique role in the analysis of various damage assessment problems encountered in the engineering field. In recent years, numerical and theoretical studies involving entropy generation methodologies have been carried out to predict and diagnose the lifetime of electronic and mechanical components. This work aimed to review previous defect analysis studies that used entropy generation methodologies for electronic and mechanical components. The methodologies are classified into two categories, namely, damage analysis for electronic devices and defect diagnosis for mechanical components. Entropy generation formulations are also divided into two detailed derivations and are summarized and discussed by combining their applications. This work is expected to clarify the relationship among entropy generation methodologies, and benefit the research and development of reliable engineering components.Electronic Components, Technology and Material

Aeshna shennong sp nov., a new species from Hubei Province, China (Odonata: Anisoptera: Aeshnidae)

Aeshna shennnong sp. nov. (holotype male: Dajiuhu national wetland park in Shennongjia National Nature Reserve, Shennongjia City, Hubei Province, China, 28. VIII. 2013) is described, illustrated and compared with its most similar congener, A. petalura Martin, 1908. The holotype will be deposited in the Collection of Aquatic Animals, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan City, Hubei Province, China. New distribution records of A. petalura from mainland China are also provided.Aeshna shennnong sp. nov. (holotype male: Dajiuhu national wetland park in Shennongjia National Nature Reserve, Shennongjia City, Hubei Province, China, 28. VIII. 2013) is described, illustrated and compared with its most similar congener, A. petalura Martin, 1908. The holotype will be deposited in the Collection of Aquatic Animals, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan City, Hubei Province, China. New distribution records of A. petalura from mainland China are also provided

Description of Chlorogomphus auripennis spec. nov from Guangdong Province, with new records of Chlorogomphidae from Yunnan Province, China (Odonata: Chlorogomphidae)

A new chlorogomphid, Chlorogomphus (Orogomphus) auripennis spec. nov. (holotype male; Mt Nankunshan, Longmen County, Guangdong Province, China, 20. V. 2008) is described and illustrated. It is the first species belonging to the sub-genus Orogomphus recorded from mainland China. The holotype will be deposited in the Collection of Aquatic Animals, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan City, Hubei Province, China. Chlorogomphus auratus Martin, 1910 and Chloropetalia selysi (Fraser, 1929) are recoded from Chinese territory for the first time. The total number of Chlorogomphidae in China reaches 20. Description of the hitherto unknown female of Chlorogomphus yokoii Karube, 1995 is provided.A new chlorogomphid, Chlorogomphus (Orogomphus) auripennis spec. nov. (holotype male; Mt Nankunshan, Longmen County, Guangdong Province, China, 20. V. 2008) is described and illustrated. It is the first species belonging to the sub-genus Orogomphus recorded from mainland China. The holotype will be deposited in the Collection of Aquatic Animals, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan City, Hubei Province, China. Chlorogomphus auratus Martin, 1910 and Chloropetalia selysi (Fraser, 1929) are recoded from Chinese territory for the first time. The total number of Chlorogomphidae in China reaches 20. Description of the hitherto unknown female of Chlorogomphus yokoii Karube, 1995 is provided

Discovery of four new species of the genus Planaeschna from Southwestern China (Odonata: Anisoptera: Aeshnidae)

Four new species of the genus Planaeschna, P. robusta sp. nov. (holotype male; Mt. Emeishan, Emeishan City, Sichuan Province, China, 16. VIII. 2007), P. maculifrons sp. nov. (holotype male; Mt. Emeishan, Emeishan City, Sichuan Province, China, 20. VIII. 2007), P. caudispina sp. nov. (holotype male; Mt. Qingchengshan, Dujiangyan City, Sichuan Province, China, 30. VIII. 2007) and P. monticola sp. nov. (holotype male; Sanjiacun Stream, Fengyi Town, Dali City, Yunnan Province, China, 19. XI. 2012) are described and illustrated and diagnosed from their congeners. All the holotypes have been deposited in the Collection of Aquatic Animals, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan City, Hubei Province, China. Brief notes on the biology of each species are also provided.Four new species of the genus Planaeschna, P. robusta sp. nov. (holotype male; Mt. Emeishan, Emeishan City, Sichuan Province, China, 16. VIII. 2007), P. maculifrons sp. nov. (holotype male; Mt. Emeishan, Emeishan City, Sichuan Province, China, 20. VIII. 2007), P. caudispina sp. nov. (holotype male; Mt. Qingchengshan, Dujiangyan City, Sichuan Province, China, 30. VIII. 2007) and P. monticola sp. nov. (holotype male; Sanjiacun Stream, Fengyi Town, Dali City, Yunnan Province, China, 19. XI. 2012) are described and illustrated and diagnosed from their congeners. All the holotypes have been deposited in the Collection of Aquatic Animals, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan City, Hubei Province, China. Brief notes on the biology of each species are also provided