Theoretical and Experimental Investigations of Thermoresistive Micro Calorimetric Flow Sensors Fabricated by CMOS MEMS Technology

Xu, Wei; Song, Kui; Ma, Shenhui; Gao, Bo; Chiu, Yi; Lee, Yi-Kuen

doi:10.1109/jmems.2016.2596282

Cited by 51 publications

(34 citation statements)

References 18 publications

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“…Micromachines 2020, 11,205 6 of 10 top-view optical micrograph (OM) images of the whole fabricated sensors presented in Figure 6c,d confirm the intact composite membrane. In addition, the scanning electron microscope (SEM) images in Figure 6a,b clarify that the size of sensor chips shrunk to 0.7 mm × 0.7 mm for both sensors.…”

Section: Fabricationmentioning

confidence: 66%

“…Micromachines 2020, 11,205 2 of 10 flow sensors are generally fabricated using double-sided micromachining [9]. With the technical approaches, thermal insulation membrane is formed by potassium hydroxide (KOH) anisotropic etching from the wafer backside.…”

Section: Sensor Designmentioning

confidence: 99%

“…Thus, developing a new strategy to minimize the chip size for realizing batch-fabrication with a lower cost is an important issue. Recently, a commercial 0.35 µm 2P4M microelectromechanical systems (MEMS) process was used in [11] to fabricate a sensor from the front-side of a (100) wafer. The approach decreased the chip-size and fabrication cost.…”

Section: Sensor Designmentioning

confidence: 99%

“…Micromachines 2020, 11,205 3 of 10 field and the temperature field. For laminar flow field, the inlet and outlet of the flow channel were established and other boundary conditions defined as no-slip.…”

Section: Sensor Designmentioning

confidence: 99%

“…Micromachines 2020, 11,205 7 of 10 operating principle of this CTD circuit is described in [14]. Our design incorporates the Wheatstone bridge readout method [15], for the type A sensor, the circuit is constituted with upstream and downstream resistors with the addition of two on-chip resistors.…”

Section: Device Characterizationmentioning

confidence: 99%

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A Front-Side Microfabricated Thermoresistive Gas Flow Sensor for High-Performance, Low-Cost and High-Yield Volume Production

Xue

Wang

2020

Micromachines

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In this paper, we present a novel thermoresistive gas flow sensor with a high-yield and low-cost volume production by using front-side microfabricated technology. To best improve the thermal resistance, a micro-air-trench between the heater and the thermistors was opened to minimize the heat loss from the heater to the silicon substrate. Two types of gas flow sensors were designed with the optimal thermal-insulation configuration and fabricated by a single-wafer-based single-side process in (111) wafers, where the type A sensor has two thermistors while the type B sensor has four. Chip dimensions of both sensors are as small as 0.7 mm × 0.7 mm and the sensors achieve a short response time of 1.5 ms. Furthermore, without using any amplification, the normalized sensitivity of type A and type B sensors is 1.9 mV/(SLM)/mW and 3.9 mV/(SLM)/mW for nitrogen gas flow and the minimum detectable flow rate is estimated at about 0.53 and 0.26 standard cubic centimeter per minute (sccm), respectively.Micromachines 2020, 11, 205 2 of 10 insulation membrane is formed by potassium hydroxide (KOH) anisotropic etching from the wafer backside. The anisotropic etching-induced inclined sidewalls cause the chip size to be quite large and the back-sided KOH etching is time-consuming, which yield a higher batch-fabrication cost [10]. Thus, developing a new strategy to minimize the chip size for realizing batch-fabrication with a lower cost is an important issue. Recently, a commercial 0.35 µm 2P4M microelectromechanical systems (MEMS) process was used in [11] to fabricate a sensor from the front-side of a (100) wafer. The approach decreased the chip-size and fabrication cost. However, the insulation membrane was released through XeF 2 isotropic etching, Thus, a depth-limited insulation cavity was formed, which would increase the heat loss, lower the thermal resistance and cause a relatively lower sensitivity of the sensor. Here, this paper expands on preliminary research presented in [12] and explores a tiny-sized ultrasensitive thermoresistive gas flow sensor that is single-side processed in an ordinary single-polished (111) silicon wafer. By changing the number of thermoresistive sensors, we developed two types of differential thermoresistive gas flow sensors, a half-bridge type and a full-bridge type.

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Section: Fabricationmentioning

confidence: 66%

Section: Sensor Designmentioning

confidence: 99%

Section: Sensor Designmentioning

confidence: 99%

Section: Sensor Designmentioning

confidence: 99%