This chip was then wire bonded and packaged with another chip produced in a semi-custom Bi-CMOS process containing the sensors’ interface circuitry. In yet another interesting work, an SOI MEMS chip containing an accelerometer along with pressure, temperature and humidity sensors has been demonstrated by Fujita et al. Similarly, Yoon and Wise reported a mass flow sensor with an on-chip CMOS interface circuitry. Silicon-On-Insulator (SOI) technology has also been used in an integrated pressure-flow sensor for correlation measurements in turbulent gas flow. A CMOS chip has also been demonstrated as a pressure-flow sensor by Li et al. Integrated flow, pressure and temperature sensing capabilities on a single silicon chip have also been reported in. reported acceleration, magnetic field, wind direction, wind speed, pressure, light intensity, humidity and temperature sensors on a single silicon die. Simultaneous utilization of multiple sensors for monitoring flow velocity, direction and ambient temperature on a single chip has also been demonstrated by Ma et al. In addition to the previous examples, sensor systems designed for laboratory and medical applications sensing temperature, fluid density and mass flow rate and fish behaviour and migration movements monitoring light, pressure, temperature and conductivity were also reported. It is worth mentioning that electronic circuit integration on a single chip, as demonstrated in, is possible using the CMOS MEMS approach and is not valid, in general, for all MEMS-based sensors. with calorimetric, capacitive and temperature sensors accompanied by the required circuits for drive and signal conditioning on the same chip. Fabrication of a sensor system using the Complementary Metal Oxide Semiconductor (CMOS) MEMS approach has been reported by Hagleitner et al. Berns and Obermeier reported Aero-MEMS sensor arrays for time-resolved measurement of pressure and wall shear stress. arranged hot film sensors in a grid for two-dimensional wall shear stress imaging. for simultaneous measurements of all three parameters in micro-channels. For example, an array of five pressure, temperature and wall shear stress sensors was integrated on a single chip by Xu et al. Generally, the need to cluster more than one sensor on a chip arises when the investigators are designing a sensor system intended for a specific industrial/scientific application.
There are quite a few examples reported in the literature, where multiple sensors have been integrated on a single MEMS chip. Furthermore, they also bring in the possibility of multiple sensors and electronic circuit integration on a single chip. Compared to their conventional counterparts, the MEMS sensors offer advantages of miniaturization, low power consumption and cost reduction.
The last two decades have witnessed a tremendous growth in the MEMS (Micro-Electro-Mechanical-Systems) market. The multi-sensor chip can be used for simultaneous measurement of fluid pressure, temperature and flow rate in fluidic experiments and aerospace/automotive/biomedical/process industries. Packaged in a micro-channel, the flow rate sensor has a linearized sensitivity of 17.3 mV/(L/min) −0.1 in the tested range of 0–4.7 L/min. The sensitivity of the pressure sensor was 0.0686 mV/(V excit kPa) with a non-linearity of 0.25% between 0 and 69 kPa above ambient pressure. With a drive current of 10 ♚–0.1 ♚, the thermodiodes exhibited sensitivities of 1.41 mV/☌–1.79 mV/☌ in the range 20–300 ☌. Independent apparatuses were used for the characterization of each sensor. Very dense sensor packing per unit area of the chip has been enabled by using technologies/processes like SOI, CMOS and DRIE. The silicon dioxide layers with embedded sensors are relieved from the substrate as membranes with the help of a single DRIE step after chip fabrication from a commercial CMOS foundry. The chip contains ten thermodiodes (temperature sensors), a piezoresistive-type pressure sensor and nine hot film-based flow rate sensors fabricated within the oxide layer of the SOI wafers. The multi-sensor chip has been designed keeping in view the requirements of researchers interested in experimental fluid dynamics. An SOI CMOS multi-sensor MEMS chip, which can simultaneously measure temperature, pressure and flow rate, has been reported.
0 kommentar(er)
