One of the key components of a chemical gas sensor is a MEMS micro-heater. Micro-heaters are used in both semiconductor gas sensors and NDIR gas sensors; however they each require different heat dissipation characteristics. For the semiconductor gas sensors, a uniform temperature is required over a wide area of the heater. On the other hand, for the NDIR gas sensor, the micro-heater needs high levels of infrared radiation in order to increase sensitivity. In this study, a novel design of a poly-Si micro-heater is proposed to improve the uniformity of heat dissipation on the heating plate. Temperature uniformity of the micro-heater is achieved by compensating for the variation in power consumption around the perimeter of the heater. With the power compensated design, the uniform heating area is increased by 2.5 times and the average temperature goes up by 40 °C. Therefore, this power compensated micro-heater design is suitable for a semiconductor gas sensor. Meanwhile, the poly-Si micro-heater without compensation shows a higher level of infrared radiation under equal power consumption conditions. This indicates that the micro-heater without compensation is more suitable for a NDIR gas sensor. Furthermore, the micro-heater shows a short response time of less than 20ms, indicating a very high efficiency of pulse driving.
In the present study, we demonstrate the performance of Zinc oxide thin film transistors (ZnO TFTs) array subjected to the strain under high bending test and the reliability of TFTs was confirmed for the bending fatigue test of 2000 cycles. Initially, ZnO TFTs were fabricated on Si substrate and subsequently transferred on flexible PET substrate using transfer printing process. It was observed that when the bending radius reached ≥ 11 mm then cracks start to initiate first at SiO 2 bridges, acting as interconnecting layers among individual TFT. Whatever the strain is applied to the devices, it is almost equivalently adopted by the SiO 2 bridges, as they are relatively weak compared to rest of the part. The initial cracking of destructed SiO 2 bridge leads to the secondary cracks to the ITO electrodes upon further increment of bending radius. Numerical simulation suggested that the strain of SiO 2 layer reached to fracture level of 0.55% which was concentrated at the edge of SiO 2 bridge layer. It also suggests that the round shape of SiO 2 bridge can be more fruitful to compensate the stress concentration and to prevent failure of device.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.