Abstract:A micromachined capacitive temperature sensor is designed and fabricated based on a multilayer cantilever. The top and bottom layers of the cantilever are Al and Si, respectively, which also serve as electrodes of the sensing capacitor. A composite Si 3 N 4 /SiO 2 layer, a dielectric layer, is sandwiched between the top and bottom electrodes. The cantilever thermal response is due to differences in thermal expansion coefficients for the Al, Si 3 N 4 /SiO 2 and silicon materials. With the effect of strain on th… Show more
“…Based on Timoshenko’s assumptions 9 , the multilayer cantilever thermal - mechanical response is analyzed 8,10 . Figure 3 shows the model of the thermo-mechanical analysis.Figure 3The model of the thermo-mechanical analysis.…”
Section: Modeling Of the Temperature Sensormentioning
confidence: 99%
“…As a result, it cannot be used in radiosondes, which requires the temperature sensor to operate at temperature as low as −90 °C. Furthermore, some types of miniature temperature sensors are lately proposed for low temperature detection fields 8 . Even so, there is almost no miniature temperature sensor compatible with CMOS manufacturing process that can operate in the range between −90 °C and 60 °C.…”
Section: Introductionmentioning
confidence: 99%
“…In order to produce a temperature sensor applicable in radiosondes, Dr. Ma in our lab proposed a micromachined monocrystalline silicon capacitive temperature sensor 8 . The experimental results show that the sensor provides a sensitivity of 7 fF/°C in the −70 to 100 °C range.…”
Section: Introductionmentioning
confidence: 99%
“…However, the fabrication process needed wet etching on the backside of silicon substrate, which could lead to ion contamination on CMOS IC and is not compatible with CMOS process. In addition, this fabrication process used by Dr. Ma chose the SOI wafer as the substrate material 8 , which was expensive and increased the cost of the sensor.…”
This paper presents a micromachined monocrystalline silicon piezoresistive temperature sensor fabricated by a surface micromachining CMOS (Complementary Metal Oxide Semiconductor) MEMS (Micro-Electro-Mechanical System) process. The design of the temperature sensor is based on the structure of the multi-layer cantilever beam and the bimetallic effect. The temperature change of the cantilever beam is translated into the change of the piezoresistance’s value. The test results show that the sensitivities of the sensors are 27.9 mV/°C with 100 Ω/▯ piezoresistance between −40 °C to 60 °C and 7.4 mV/°C with 400 Ω/▯ piezoresistance between −90 °C to 60 °C. The temperature sensor proposed in this paper can be used in radiosondes for its low operating temperature (as low as −90 °C), small size (below 1 mm2) and low heat capacity.
“…Based on Timoshenko’s assumptions 9 , the multilayer cantilever thermal - mechanical response is analyzed 8,10 . Figure 3 shows the model of the thermo-mechanical analysis.Figure 3The model of the thermo-mechanical analysis.…”
Section: Modeling Of the Temperature Sensormentioning
confidence: 99%
“…As a result, it cannot be used in radiosondes, which requires the temperature sensor to operate at temperature as low as −90 °C. Furthermore, some types of miniature temperature sensors are lately proposed for low temperature detection fields 8 . Even so, there is almost no miniature temperature sensor compatible with CMOS manufacturing process that can operate in the range between −90 °C and 60 °C.…”
Section: Introductionmentioning
confidence: 99%
“…In order to produce a temperature sensor applicable in radiosondes, Dr. Ma in our lab proposed a micromachined monocrystalline silicon capacitive temperature sensor 8 . The experimental results show that the sensor provides a sensitivity of 7 fF/°C in the −70 to 100 °C range.…”
Section: Introductionmentioning
confidence: 99%
“…However, the fabrication process needed wet etching on the backside of silicon substrate, which could lead to ion contamination on CMOS IC and is not compatible with CMOS process. In addition, this fabrication process used by Dr. Ma chose the SOI wafer as the substrate material 8 , which was expensive and increased the cost of the sensor.…”
This paper presents a micromachined monocrystalline silicon piezoresistive temperature sensor fabricated by a surface micromachining CMOS (Complementary Metal Oxide Semiconductor) MEMS (Micro-Electro-Mechanical System) process. The design of the temperature sensor is based on the structure of the multi-layer cantilever beam and the bimetallic effect. The temperature change of the cantilever beam is translated into the change of the piezoresistance’s value. The test results show that the sensitivities of the sensors are 27.9 mV/°C with 100 Ω/▯ piezoresistance between −40 °C to 60 °C and 7.4 mV/°C with 400 Ω/▯ piezoresistance between −90 °C to 60 °C. The temperature sensor proposed in this paper can be used in radiosondes for its low operating temperature (as low as −90 °C), small size (below 1 mm2) and low heat capacity.
“…Examples include resistance temperature detector (RTD) sensors [6], pyroelectric sensors [7,8] and capacitive sensors [9]. This paper presents the use of a commercially available, cheap ferroelectric sensor based on lead zirconate titanate (PZT) applied to a developing wearable electronics setting, whereby temperature of everyday objects including human body temperature can be measured continuously.…”
Abstract-Response of a ferroelectric capacitor to static temperature (~22 to 90°C) is presented. The sensor is based on ferroelectric ceramic lead zirconate titanate (PZT). The PZT sensor is a cheap, commercially available element used to provide a proof of concept for the initial investigation into using ferroelectric materials for the monitoring of static temperature. The capacitor response to temperature was measured using PZT capacitance changes recorded at 1 kHz. The capacitance was measured after the temperature had stabilised. We have found that the PZT capacitor responds linearly as a function of applied temperature, with a sensitivity ~ 53 pF/°C. Furthermore, to provide some initial electronics capable of measuring sensor capacitance in real time, the PZT element was attached to an Arduino Uno platform. Again, the sensor continues to respond linearly to temperature with a sensitivity of 146 pF/°C. The system developed paves the way for further work to be done on using ferroelectric materials for the monitoring of static temperature changes, for applications such as human body temperature measurement using a textile-based smart-shirt setup.
Capacitive sensors have advanced rapidly to create new applications including wearable sensors for human health monitoring, integrated sensors for intelligent surgical devices, tactile interfaces for robots. Compared to other types of pressure or strain sensors, capacitive sensors require low power consumption and offer excellent linearity and fast response time. Herein, this review concentrates on the recent advancements and developments of high‐performance capacitive sensors with new materials and microstructures, which significantly enhance their sensitivity, accuracy, linearity, and response time. This work also provides a review of recent applications, from which current challenges and future opportunities are proposed and discussed.
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