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Abstract

Results about energy capture from the environment associated with the self-powering of a wireless sensor network (WSN) for structural health monitoring of aircrafts (SHM) are presented. Thermal gradients taking place during specific flight phases are converted into electrical energy by using a small water tank coupled to a thermoelectric generator which output is connected to a storage circuit. The proposed system is experimentally assessed in an environmental chamber. Regarding the energy storage issue, considering the operating temperature (-55°C) and the amount of energy, supercapacitors are suggested instead of batteries. For capacitors charging and later use of energy, a circuit based on a voltage booster associated with a DC-DC regulator is designed and simulated.

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Abstract

Improving the ESD robustness of integrated protection structures to cope with the constraints of severe environments such as the automotive one is a real challenge. Getting a deep understanding of the involved high injection physics during an ESD stress helps defining specific design guidelines. The grounded-base NPN bipolar transistor is a popular and efficient protection device. In this paper, we explore the impact of crystal orientation on the electrical characteristics and the robustness of this device. It is shown for the first time that orienting the structure 45° with respect to the wafer flat allows significantly improving its on-resistance. A 30% improvement is measured on the device under study.

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Abstract

RF MEMS are commonly known as electrostatic devices using high electric field for their actuation. They can be exposed to transient voltages in any environment, and are very sensitive. According to this point of view, it is necessary to understand and analyze the degradations and failure criteria that can make them useless or reduce their lifetime. This paper deals with the investigation of ESD failure signature in capacitive RF MEMS. ESD experiments were carried out using a transmission line pulsing technique. It has been observed that electrical discharges give rise to sparks or electrical arcing and induced DC parameter shift, which can directly lead to changes in RF metrics. The contact-less dielectric charging effects of ESD pulses have been reported in this paper. It has been found that induced charges are predominant compared to injected ones through the trend of slope of the shift in the voltage corresponding to the minimum of capacitance.

Abstract

This paper presents a validation of the methodology based upon backside laser irradiations to characterize the sensitivity of power devices towards Single-Event Burnout. This is done thanks to high-energy heavy ion testing and device simulations.

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This paper proposes a 1D-analytical description of the injection ratio of a self-biased bipolar transistor under very high current injection conditions. Starting from an expression of the current gain based on the stored charge into the emitter and base regions, we derive a new analytical expression of the current injection ratio. This analytical description demonstrates the presence of an asymptotic limit for the injection ratio at very high current densities, as the ratio of electron/hole mobilities in the case of an NPN transistor and to the ratio of hole/electron saturation velocities for a PNP. Moreover, for the first time, a base narrowing effect is demonstrated and explained in the case of a self-biased PNP, in contrast with the base widening effect (Kirk effect [Kirk CT, A theory of transistor cutoff frequency (fT) falloff at high current densities, IRE Trans Electr Dev 1961: p. 16473]) reported for lower current density. These results are validated by numerical simulation and show a good agreement with experimental characterizations of transistors especially designed to operate under extreme condition such as electrostatic discharge (ESD) events

Abstract

Various optical defect localization techniques are applied on the same integrated circuits (IC). These circuits were previously stressed by Electro Static Discharges (ESD) to create defects. The results obtained by each technique were analyzed to determine the nature of the defects. The different data are compared to assess their sensitivity and to evaluate the contribution of each technique in a failure analysis flow.

Abstract

In this paper, it is demonstrated that low frequency noise measurements are an efficient tool for the detection of latent defects induced by CDM stress in a complex circuit such as a DCDC converter. This technique is able to detect the presence of a defect whereas classical electrical testing techniques such as Iddq or functionality test fail. In addition, a correlation between the noise signature and the nature of the defect is established. In particular, the presence of trapped charges in the oxides is clearly identified.

Abstract

We present in this study the effect of electrical ageing on silicon (Si) NPN bipolar transistors. This study is based on a sample of halfhundred components, which have been fabricated in the early 1980s, which represents an exceptional experience feedback. By means of static and low frequency noise measurements, which are used as diagnostic tools for reliability assessment, we have noticed a good accordance with a physical model based on an oxide charge modulation. We have also used emission microscopy and electron beam-induced current analysis in order to visualize and to localize the defects in the structure. These have been located in the spacer oxide at the periphery of the base-emitter junction.