AVS 52nd International Symposium
    MEMS and NEMS Monday Sessions
       Session MN-MoP

Paper MN-MoP6
CO Gas Sensor based on a Doped ZnO Film with a Microhotplate/Floating-Gate MIS Structure

Monday, October 31, 2005, 5:00 pm, Room Exhibit Hall C&D

Session: General Aspects of MEMS and NEMS Poster Session
Presenter: W. Calleja-Arriaga, Inaoe Mexico
Authors: W. Calleja-Arriaga, Inaoe Mexico
J. De la Hidalga-Wade, Inaoe Mexico
A. Heredia-Jimenez, Upaep Puebla-Mexico
G. Rosas-Guevara, Inaoe Mexico
I. Juarez-Ramirez, Inaoe Mexico
C. Zuñiga-Islas, Inaoe Mexico
N. Carlos-Ramirez, Inaoe Mexico
P. Alarcon-Peña, Inaoe Mexico
L. Tecuapetla-Quechol, Inaoe Mexico
M. Escobar-Aguilar, Inaoe Mexico
J. Silva, Inaoe Mexico
J.L. Gonzalez-Vidal, Citis-Uaeh Mexico
M.A. Reyes-Barranca, Cinvestav Mexico
M.L. Olvera, Cinvestav Mexico
A. Maldonado, Cinvestav Mexico
Correspondent: Click to Email
Doped and undoped zinc oxide (ZnO) single thin films, used as the active element in a gas microsensor, is presented in this work. The gas sensor arrangement is based on a double polysilicon micro-hotplate (MHP) and a polysilicon floating gate MIS transistor (FG-MIS). The ZnO films were doped with 6% of either copper, chromium, or gallium. The ZnO film, with an active area of 80x80 microns, was deposited onto a polysilicon plate that forms the gate of the MIS transistor. This sensing section is heated by a U-shaped polysilicon stripe, which is located beneath the polysilicon plate and electrically isolated from it by nitride/oxide films. The microhotplate is thermally isolated using a deep cavity micromachined in the silicon substrate, and mechanically supported by four polysilicon arms. The sensing film induces a charge in the floating-gate in such a way that the channel conductance is modulated. The sensor structure was characterized by detecting carbon monoxide (CO) at 300 ºC. Finally, a complete procedure of fabrication of this sensor structure will be presented at the conference.