Self-aligned process for the development of surface stress capacitive biosensor arrays

A new fabrication process and first experimental results of a surface stress based capacitive biosensor array are presented. Flexible membranes and a fixed electrode on the substrate constitute the capacitive sensors. 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. The process is characterized by the self-alignment of the sensitive flexible membranes and the use of silicon fusion bonding to fabricate the complete device. First experimental results on biosensing indicate that the sensors are able to detect the hybridization of beta-thalassemia oligonucleotides.