The application of pressure sensors in harsh environments is typically hindered by the stability of the material over long periods of time. This work focuses on the design and fabrication of surface micromachined Pirani gauges which are designed to be compatible with state-of-the-art Silicon Carbide CMOS technology. Such an integrated platform would boost harsh environment compatibility while reducing the required packaging complexity. An analytical model was derived describing the design variables of the Pirani gauges followed by Finite Element Analysis. The Pirani gauges were fabricated in a CMOS compatible cleanroom with a process employing only three masks, thus suitable for mass production. The SiC-based Pirani gauge is far more competitive than the traditional Si-based Pirani gauge in terms of endurance in hightemperature environments. From 25°C to 650°C, the gauge shows a reproducible response to pressure changes and has a maximum sensitivity of 17.63 Ω/Pa at room temperature, and of 1.23 Ω/Pa at 650°C. Additionally, some of the gauges were demonstrated to operate at temperatures up to 750°C.

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The thermal-piezoresistive effect in silicon (Si) has attracted great attention toward high-performance resonant devices but still faces major challenges for harsh environment applications. Instead of using Si, this paper, for the first time, reports a thermal-piezoresistive resonator based on a silicon carbide-on-insulator (SiCOI) platform. The resonance frequency simulation, CMOS-compatible fabrication, and thermoresistive properties characterization of the proposed SiCOI resonator are presented. The experimental results show linear current-voltage characteristics and a constant temperature coefficient of resistance (TCR) up to 200 °C.

The continuous downscaling of microelectronics has introduced many reliability issues on interconnect. Electromigration and dewetting are major reliability concerns in high-temperature micro-and nanoscale devices. In this paper, the local dewetting of copper thin film during the electromigration test was first found and investigated. When the high current was applied, the dewetted copper forming around the edge was observed at the cathode of the conductor. Furthermore, the effect of temperature and conductor size on local dewetting was investigated. Our proposed mechanism for local dewetting is in good agreement with experimental findings.

Fabricating high-aspect-ratio (HAR) structures with silicon carbide (SiC) is a challenging task. This paper presents a silicon carbide (SiC) reinforced vertically aligned carbon nanotubes (VACNT) composite as a promising candidate to fabricate HAR MEMS devices for harsh environment applications. The use of a VACNT array allows the fast realization of HAR structures as a template for MEMS fabrication. The template can later be easily filled by amorphous-SiC due to the porous nature of the VACNT forest. The SiC-CNT nanocomposite has electrical properties dominated by VACNT arrays and mechanical stability dominated by the a-SiC. Based on this concept, a thermal actuator is fabricated and proven to function up to 450°C for the first time.