Sensors and actuators b-chemical vol:78 issue:1-3 pages:221-227
In this paper, we propose a new structure for a glucose sensor fabricated by micromachining techniques with the working electrode separated from the enzyme membrane. In this sensor, an array of microholes is etched through a silicon membrane. On the sidewalls of these microholes, a working electrode is formed by platinum sputtering. On the top of the microholes, a membrane of glucose oxidase (GOD) is deposited. Owing to the separation of the working electrode and the enzyme membrane, standard MEMS processes can be carried out as the front-end processes during the fabrication. The enzyme membrane will be deposited as the last process step. This avoids the problem of incompatibility between MEMS processes and biomaterials. In this way, the glucose sensor can be easily integrated in the microchannel. The diffusion of hydrogen peroxide in the microholes was simulated with different ratios of depth and diameter. It is shown that when the ratio of diameter and depth of the microholes is 1, most of the produced hydrogen peroxide can be oxidized at the working electrode on the sidewalls of microholes. Laser drilling and magnetron RIE were exploited, respectively, to fabricate the array of microholes. The responses of both the stand-alone sensor and the sensor integrated in the microchannel are shown. (C) 2001 Elsevier Science B.V. All rights reserved.