Title :
Gas sensor fabricated in commercial CMOS technology
Author :
Srivastava, A. ; George, N.
Author_Institution :
Dept. of Electr. & Comput. Eng., Louisiana State Univ., Baton Rouge, LA, USA
fDate :
31 Mar-2 Apr 1996
Abstract :
Reports the design of a bulk-micromachined gas sensor fabricated in commercial 2 μm n-well CMOS technology using a high level computer aided design tool. The gas sensor is a palladium-oxide-polysilicon micromachined MOS structure. The design includes an additional layer in CMOS called `open´ which enables the formation of a `cavity´ in the silicon substrate. After the fabrication of CMOS chips single maskless etch in an aqueous solution of ethylenediamine-pyrocatechol (EDP) or xenon difluoride (XeF2) is done to create a cavity. This results in a micromachined structure with the polysilicon and the oxide on it, suspended over the `cavity´ formed. Finally palladium is deposited over the micromachined structure in a high vacuum evaporator. The adsorption of the hydrogen gas in palladium changes C-V characteristics of the MOS structure. In the present work we report part of the studies on gas sensor development
Keywords :
MIS devices; etching; gas sensors; micromachining; microsensors; semiconductor technology; 2 micron; C-V characteristics; CMOS technology; H; Pd-SiO2-Si; adsorption; aqueous solution; bulk micromachining; cavity; ethylenediamine-pyrocatechol; fabrication; gas sensor; high level computer aided design tool; open layer; palladium-oxide-polysilicon MOS structure; silicon substrate; single maskless etch; vacuum evaporation; xenon difluoride; CMOS technology; Chemical industry; Circuits; Etching; Fabrication; Gas detectors; Hydrogen; Palladium; Silicon; Substrates;
Conference_Titel :
System Theory, 1996., Proceedings of the Twenty-Eighth Southeastern Symposium on
Conference_Location :
Baton Rouge, LA
Print_ISBN :
0-8186-7352-4
DOI :
10.1109/SSST.1996.493526
