Self-Aligned Process for the Development of Surface Stress Capacitive Biosensor Arrays

The fabrication process of a surface stress based capacitive biosensor array is presented. Flexible membranes and a fixed electrode on the substrate constitute the capacitive biosensors. Probe molecules are immobilized on the membrane surface and the surface stress variations during biological interactions force the membrane to deflect and effectively change the capacitance between the flexible membrane and the fixed substrate. The array consists of 60 sensors and thus is suitable for parallel sensing. Through the presented fabrication process, which is described in detail, sensitive membranes can be created. The process simplicity and the increased sensitivity of the biosensors are related to the use of boron implantation and the consequent self-aligned creation of the conductive membranes after the silicon fusion bonding technique. (C) 2011 Published by Elsevier Ltd.