MEMS flow sensors for nano-fluidic applications

Author

Wu, S. ; Lin, Q. ; Yuen, Y. ; Tai, Y.C.

Author_Institution

Dept. of Electr. Eng., California Inst. of Technol., Pasadena, CA, USA

fYear

2000

fDate

23-27 Jan 2000

Firstpage

745

Lastpage

750

Abstract

This paper presents micromachined thermal sensors for measuring liquid flow rates in the nanoliter-per-minute range. The sensors use a boron-doped polysilicon thin-film heater that is embedded in the silicon nitride wall of a microchannel. The boron doping is chosen to increase the heater´s temperature coefficient of resistance within tolerable noise limits. And the microchannel is suspended from the substrate to improve thermal isolation. The sensors have demonstrated a flow rate resolution below 10 nL/min, as well as the capability for detecting micro bubbles in the liquid. Heat transfer simulation has also been performed to explain the sensor operation and yielded good agreement with experimental data

Keywords

flow measurement; microfluidics; micromachining; microsensors; MEMS flow sensor; Si:B; Si₃N₄; boron doping; heat transfer simulation; liquid flow measurement; micro bubble detection; microchannel flow; micromachining; nano-fluidic system; noise; polysilicon thin film heater; silicon nitride wall; temperature coefficient of resistance; thermal isolation; thermal sensor; Boron; Electrical resistance measurement; Fluid flow; Fluid flow measurement; Microchannel; Micromechanical devices; Semiconductor thin films; Silicon; Thermal sensors; Thin film sensors;

fLanguage

English

Publisher

ieee

Conference_Titel

Micro Electro Mechanical Systems, 2000. MEMS 2000. The Thirteenth Annual International Conference on

Conference_Location

Miyazaki

ISSN

1084-6999

Print_ISBN

0-7803-5273-4

Type

conf

DOI

10.1109/MEMSYS.2000.838611

Filename

838611