High temperature SiC pressure sensors with low offset voltage shift

2014 ◽  
Author(s):  
Robert S. Okojie ◽  
Dorothy Lukco ◽  
Vu Nguyen ◽  
Ender Savrun
Keyword(s):  
High Temperature ◽  
Pressure Sensors ◽  
Voltage Shift ◽  
Offset Voltage ◽  
Low Offset

Thin Film Polymer Stress Measurement Using Piezoresistive Anisotropically Etched Pressure Sensors

1996 ◽  
Vol 436 ◽  
Author(s):  
G. Bitko ◽  
R. Harries ◽  
J. Matldn ◽  
A. C. McNeil ◽  
D. J. Monk ◽  
...  
Keyword(s):  
Thin Film ◽  
Thermal Stress ◽  
High Temperature ◽  
Material Properties ◽  
Applied Pressure ◽  
Pressure Sensors ◽  
Offset Voltage ◽  
High Temperature Storage ◽  
Linear Expression ◽  
Temperature Storage

AbstractSilicon bulk micromachined piezoresistive pressure sensors are very sensitive to applied stresses: that is, applied pressure and/or packaging-related stresses. Device encapsulation has been observed to affect the electrical output of the pressure sensor significantly. The magnitude of the zero applied pressure output voltage (i.e., the offset voltage) that can be attributed to a thin film encapsulant is proportional to the magnitude of the roomtemperature thermal stress of that film. Parylene C coatings have been used as encapsulants in this work. Finite element and analytical modeling techniques were used to evaluate the effect of material property variation on the offset of a pressure sensor. A simple, linear expression of offset as a function of a material property parametric group, that includes: parylene thickness, parylene biaxial modulus, parylene CTE, silicon thickness, and annealing temperature; has been established. Experimental analysis of parylene coated pressure sensors and parylene coated silicon and gallium arsenide wafers was performed to confirm the resulting model. Known variations in parylene material properties caused by processing (i.e., uncontrolled deposition, annealing, and high temperature storage) have been used as an experimental vehicle for this purpose. An empirical relationship between offset voltage on parylene coated devices and room-temperature thermal stress on parylene coated wafers that have been exposed to the same processing is a linear expression with a similar slope to the modeling results. Furthermore, stress measurements from parylene coated silicon wafers and parylene coated gallium arsenide wafers have been used to estimate the parylene biaxial modulus (approximately 5000 MPa) and the parylene CTE (approximately 50 ppm/°C) independently. These material properties were observed to shift following parylene annealing and high temperature storage exposure experiments in a manner that is consistent with the established model.

scholarly journals Study on the Stability of the Electrical Connection of High-Temperature Pressure Sensor Based on the Piezoresistive Effect of P-Type SiC

Micromachines ◽  
2021 ◽  
Vol 12 (2) ◽  
pp. 216
Author(s):  
Yongwei Li ◽  
Ting Liang ◽  
Cheng Lei ◽  
Qiang Li ◽  
Zhiqiang Li ◽  
...  
Keyword(s):  
High Temperature ◽  
Pressure Sensor ◽  
Pressure Sensors ◽  
Extreme Environment ◽  
Maximum Temperature ◽  
Piezoresistive Effect ◽  
Electrical Connection ◽  
Contact Stability ◽  
The Stability ◽  
P Type

In this study, a preparation method for the high-temperature pressure sensor based on the piezoresistive effect of p-type SiC is presented. The varistor with a positive trapezoidal shape was designed and etched innovatively to improve the contact stability between the metal and SiC varistor. Additionally, the excellent ohmic contact was formed by annealing at 950 °C between Ni/Al/Ni/Au and p-type SiC with a doping concentration of 1018cm−3. The aging sensor was tested for varistors in the air of 25 °C–600 °C. The resistance value of the varistors initially decreased and then increased with the increase of temperature and reached the minimum at ~450 °C. It could be calculated that the varistors at ~100 °C exhibited the maximum temperature coefficient of resistance (TCR) of ~−0.35%/°C. The above results indicated that the sensor had a stable electrical connection in the air environment of ≤600 °C. Finally, the encapsulated sensor was subjected to pressure/depressure tests at room temperature. The test results revealed that the sensor output sensitivity was approximately 1.09 mV/V/bar, which is better than other SiC pressure sensors. This study has a great significance for the test of mechanical parameters under the extreme environment of 600 °C.

scholarly journals A Ceramic Diffusion Bonding Method for Passive LC High-Temperature Pressure Sensor

Sensors ◽  
2018 ◽  
Vol 18 (8) ◽  
pp. 2676
Author(s):  
Chen Li ◽  
Boshan Sun ◽  
Yanan Xue ◽  
Jijun Xiong
Keyword(s):  
High Temperature ◽  
Pressure Sensor ◽  
Pressure Sensors ◽  
Alumina Ceramic ◽  
Harsh Environments ◽  
Ceramic Substrates ◽  
Integrated Technology ◽  
All Ceramic ◽  
Test Platform ◽  
Bonding Method

Alumina ceramic is a highly promising material for fabricating high-temperature pressure sensors. In this paper, a direct bonding method for fabricating a sensitive cavity with alumina ceramic is presented. Alumina ceramic substrates were bonded together to form a sensitive cavity for high-temperature pressure environments. The device can sense pressure parameters at high temperatures. To verify the sensitivity performance of the fabrication method in high-temperature environments, an inductor and capacitor were integrated on the ceramic substrate with the fabricated sensitive cavity to form a wireless passive LC pressure sensor with thick-film integrated technology. Finally, the fabricated sensor was tested using a system test platform. The experimental results show that the sensor can realize pressure measurements above 900 °C, confirming that the fabricated sensitive cavity has excellent sealing properties. Therefore, the direct bonding method can potentially be used for developing all-ceramic high-temperature pressure sensors for application in harsh environments.

Epoxy-free high-temperature fiber optic pressure sensors for gas turbine engine applications

2004 ◽  
Author(s):  
Juncheng Xu ◽  
Gary Pickrell ◽  
Bing Yu ◽  
Ming Han ◽  
Yizheng Zhu ◽  
...  
Keyword(s):  
High Temperature ◽  
Gas Turbine ◽  
Fiber Optic ◽  
Pressure Sensors ◽  
Gas Turbine Engine ◽  
Turbine Engine

CMOS-compatible capacitive high temperature pressure sensors

2000 ◽  
Vol 85 (1-3) ◽  
pp. 147-152 ◽  
Author(s):  
Klaus Kasten ◽  
Jörg Amelung ◽  
Wilfried Mokwa
Keyword(s):  
High Temperature ◽  
Pressure Sensors ◽  
Cmos Compatible
Sign in / Sign up

Export Citation Format

Share Document