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Abstract

A reliable factorial experimental design was applied to DRIE for specifically producing high-aspect ratio trenches. These trenches are to be used in power electronics applications such as active devices: deep trench superjunction MOSFET (DT-SJMOSFET) and passive devices: 3D integrated capacitors. Analytical expressions of the silicon etch rate, the verticality of the profiles, the selectivity of the mask and the critical loss dimension were extracted versus the process parameters. The influence of oxygen in the passivation plasma step was observed and explained. Finally, the analytical expressions were applied to the devices objectives. A perfectly vertical trench 100-¼m deep was obtained for DT-SJMOSFET. Optimum conditions for reaching high-aspect ratio structures were determined in the case of high-density 3D capacitors.

Mots-Clés / Keywords

High aspect ratio; DRIE; DoE; Power electronics;

Abstract

High-k ZrO2 thin films suitable for microelectronics applications were deposited by DLI-MOCVD method on planar Si (1 0 0) and pores etched in Si (1 0 0). The effects of various experimental parameters such as temperature of substrates, injection frequency, concentration of the precursor and oxygen partial pressure in the reactive chamber, were investigated in order to produce a single tetragonal ZrO2 phase which exhibits, according to the literature, the best permittivity. Taking into account the crystal structure, microstructure and chemistry of the films, the expected phase was successfully deposited for high temperature of substrates, relatively high feeding rate and low oxygen partial pressure. Although the 3D coverage is actually not perfect in high aspect ratio pores, the electric properties of this sample are very promising with permittivity up to 27.

Abstract

In this paper, we present the realization of a new self-controlled integrated power switch dedicated to selfswitching mode power converters. To achieve this function, an original topology based on an IGBT is proposed. Its operating modes are analyzed using 2D physical simulation. To realize this new power switch, a technological process compatible with the IGBT process and with 3D capacitors realization is proposed.

Abstract

Vibration harvesting has been intensively developed recently and systems have been simulated and realized, but real-life situations (including aircraft Structure Health Monitoring (SHM) involve uneven, low amplitude, low frequency vibrations. In such an unfavorable case, it is very likely that no power can be harvested for a long time. To overcome this, multi-source harvesting is a relevant solution, and in our application both solar and thermal gradient sources are available. We propose in this paper a complete Microsystem including a piezoelectric vibration harvesting module, thermoelectric conversion module, signal processing electronics and supercapacitor. A model is proposed for these elements and a VHDL-AMS simulation of the whole system is presented, showing that the vibration harvesting device alone cannot supply properly a SHM wireless node. Its role is nevertheless important since it is a more reliable source than thermoelectric generators (which depends on climatic conditions). Moreover, synergies between vibration harvesting and thermoelectric scavenging circuits are presented.

Mots-Clés / Keywords

SHM; Energy harversting; Scavenging; Piezoelectric; Thermoelectric; Supercapacitor; VHDL-AMS; Simulation; MEMS;