Retour au site du LAAS-CNRS

Abstract

This paper addresses an innovative solution to develop a circuit to perform accelerated stress tests of capacitive microelectromechanical-system (MEMS) switches and shows the use of instruments and equipment to monitor physical aging phenomena. A dedicated test circuit was designed and fabricated in order to meet the need for accelerated techniques for those structures. It integrated an in-house miniaturized circuit connected to additional test equipment (e.g., oscilloscopes and capacitance meters) that enabled the reliability characterization of capacitive switches. The accelerated stress test (AST) circuit generated an electrostatic-discharge-like impulse that stressed the device. This setup allowed the simultaneous measurement of the current and voltage waveforms, and the capacitance variation of the device under test after each stress. The results obtained using the miniature AST circuit were discussed and were correlated with results obtained using a commercial human-body-model tester as well as data from a cycling benchmark. The scope of this paper encompasses the theory, methodology, and practice of measurement; the development of a testing miniaturized board; and the analysis and representation of the information obtained from a set of measurements. As a result, it may contribute to the scientific and technical standards in the field of instrumentation and measurement of electrostactically actuated devices having insulating layers.

Abstract

A new junction termination for high-voltage devices using a deep trench filled with dielectric, which dramatically decreases the junction-termination area, is proposed and fabricated. The termination breakdown voltage dependence on the dielectric critical electric field (E Cd) and its permittivity (epsivrd) is theoretically studied. Finally, the proposed junction termination is experimentally validated using BenzoCycloButene (BCB) as dielectric material. Experimental results show that the proposed termination sustains more than 1200 V with a 70-mum-width and 100- mum-depth trench filled by BCB.

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

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.

Mots-Clés / Keywords

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.