Highly Responsive Metal Oxide (V2O5)-Based NEMS Pirani Gauge for In-Situ Hermeticity Monitoring

Garg, Manu; Arya, Dhairya Singh; Sharma, Sumit; Kumar, Sushil; Uddin, Wasi; Das, Samaresh; Chiu, Yi; Singh, Pushpapraj

doi:10.1109/jmems.2021.3072005

Cited by 14 publications

(8 citation statements)

References 12 publications

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“…Thermal conductivity of a homogeneous solid material remains constant under a certain temperature, which is independent of the variation of gas pressure [ 3 ]. The thermal conductance by the solid can be evaluated according to Fourier’s Law of heat conduction [ 7 , 18 , 19 , 20 ]:

where

is the thermal conductivity of the cantilever beam,

is the cross-sectional area of the contact position of the cantilever beam and the sensor wall, and

is the length of the cantilever beam. Since there are four cantilevers, the thermal conductance by the solid should be multiplied by four.…”

Section: Principle and Heat Transfermentioning

confidence: 99%

“…The Pirani gauge in reference [ 6 ] has a large measuring range but low sensitivity in the low- and high-pressure range, which reduces the practical performance. In addition, the Pirani gauges in references [ 1 , 2 , 3 , 7 , 8 ] have generally smaller ranges. Furthermore, the Pirani gauges in references [ 4 , 9 , 10 , 11 , 12 , 13 , 14 ] have problems relating to complex structure, difficult manufacturing processes, and high cost.…”

Section: Introductionmentioning

confidence: 99%

“…The novel Pirani vacuum gauge we proposed uses a VOx membrane as the thermosensitive layer to achieve high sensitivity at high vacuum. The high temperature coefficient of resistance (TCR) of VOx increased the sensitivity of the Pirani vacuum gauge, while low thermal conductivity reduced the detection limit [ 7 ]. In addition, we optimized the floating structure to decrease the thermal conductivity so that the detecting range of the Pirani gauge tended to be in the low-pressure end.…”

Section: Introductionmentioning

confidence: 99%

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Design of a High Sensitivity Pirani Gauge Based on Vanadium Oxide Film for High Vacuum Measurement

Guo

Feng

Chen

et al. 2022

Sensors

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We have designed a hot-plate-type micro-Pirani vacuum gauge with a simple structure and compatibility with conventional semiconductor fabrication processes. In the Pirani gauge, we used a vanadium oxide (VOx) membrane as the thermosensitive component, taking advantage of the high temperature coefficient of resistance (TCR) of VOx. The TCR value of VOx is −2%K−1∼−3%K−1, an order of magnitude higher than those of other thermal-sensitive materials, such as platinum and titanium (0.3%K−1∼0.4%K−1). On one hand, we used the high TCR of VOx to increase the Pirani sensitivity. On the other hand, we optimized the floating structure to decrease the thermal conductivity so that the detecting range of the Pirani gauge was extended on the low-pressure end. We carried out simulation experiments on the thermal zone of the Pirani gauge, the width of the cantilever beam, the material and thickness of the supporting layer, the thickness of the thermal layer (VOx), the depth of the cavity, and the shape and size. Finally, we decided on the basic size of the Pirani gauge. The prepared Pirani gauge has a thermal sensitive area of 130 × 130 μm2, with a cantilever width of 13 μm, cavity depth of 5 μm, supporting layer thickness of 300 nm, and VOx layer thickness of 110 nm. It has a dynamic range of 10−1~104 Pa and a sensitivity of 1.23 V/lgPa. The VOx Pirani was designed using a structure and fabrication process compatible with a VOx-based uncooled infrared microbolometer so that it can be integrated by wafer level. This work contains only our MEMS Pirani gauge device design, preparation process design, and readout circuit design, while the characterization and relevant experimental results will be reported in the future.

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where

is the thermal conductivity of the cantilever beam,

is the cross-sectional area of the contact position of the cantilever beam and the sensor wall, and

is the length of the cantilever beam. Since there are four cantilevers, the thermal conductance by the solid should be multiplied by four.…”

Section: Principle and Heat Transfermentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Design of a High Sensitivity Pirani Gauge Based on Vanadium Oxide Film for High Vacuum Measurement

Guo

Feng

Chen

et al. 2022

Sensors

View full text Add to dashboard Cite

show abstract

“…Since its invention, the quest for wider dynamic range, power efficiency, and improved sensitivity has been active [8][9][10][11][12][13][14][15]. Different approaches based on structural and dimensional optimizations were proposed for improving the gauge performance [9].…”

Section: Introductionmentioning

confidence: 99%

Electrostatically actuated all metal MEMS Pirani gauge with tunable dynamic range

Garg,

Arya,

Kumar

et al. 2024

J. Micromech. Microeng.

Self Cite

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An electrostatically actuated all-metal MEMS Pirani gauge with a tunable dynamic range is proposed. Contrary to the conventional fixed gap Pirani gauges, an electrostatic mechanism is employed to tune the gaseous conduction gap. Due to the electrostatic force between the heating element and heat sink, this tuning results in shifting the transition pressure to a higher pressure. As a result, the operating range of the Pirani gauge can be tuned depending on the magnitude of the actuation voltage. Theoretical estimation of the transition pressure corresponding to different gaseous conduction gaps is also presented. Depending on the available margin of gap tuning, the electromechanical and electrothermal analyses are carried out in COMSOL Multiphysics. The analytical approach is validated by experimentally characterizing the fabricated device. The experimentally tested device with the proposed actuation mechanism shows an 11.2 dB increase in dynamic range in comparison to the conventional design. In a CMOS-compatible fabrication process flow, the proposed gauge can be used to monitor vacuum from 40 Pa to 5×10^5 Pa with the electrostatic actuation.

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“…After a long period of development and improvement, Pirani sensors are now widely used in many fields involving vacuum monitoring [22][23][24][25][26][27][28], such as automotive industry, food processing and others. Although traditional Pirani sensors are very classic, they are large, costly, laborious and have difficulty in mass production [29].…”

Section: Introductionmentioning

confidence: 99%

Overview of the MEMS Pirani Sensors

Zhou

Shi

et al. 2022

Micromachines

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Vacuum equipment has a wide range of applications, and vacuum monitoring in such equipment is necessary in order to meet practical applications. Pirani sensors work by using the effect of air density on the heat conduction of the gas to cause temperature changes in sensitive structures, thus detecting the pressure in the surrounding environment and thus vacuum monitoring. In past decades, MEMS Pirani sensors have received considerable attention and practical applications because of their advances in simple structures, long service life, wide measurement range and high sensitivity. This review systematically summarizes and compares different types of MEMS Pirani sensors. The configuration, material, mechanism, and performance of different types of MEMS Pirani sensors are discussed, including the ones based on thermistors, thermocouples, diodes and surface acoustic wave. Further, the development status of novel Pirani sensors based on functional materials such as nanoporous materials, carbon nanotubes and graphene are investigated, and the possible future development directions for MEMS Pirani sensors are discussed. This review is with the purpose to focus on a generalized knowledge of MEMS Pirani sensors, thus inspiring the investigations on their practical applications.

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Highly Responsive Metal Oxide (V₂O₅)-Based NEMS Pirani Gauge for In-Situ Hermeticity Monitoring

Cited by 14 publications

References 12 publications

Design of a High Sensitivity Pirani Gauge Based on Vanadium Oxide Film for High Vacuum Measurement

Design of a High Sensitivity Pirani Gauge Based on Vanadium Oxide Film for High Vacuum Measurement

Electrostatically actuated all metal MEMS Pirani gauge with tunable dynamic range

Overview of the MEMS Pirani Sensors

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