Scanning probe arrays for life sciences and nanobiology applications

Various 1D and 2D scanning probe arrays with integrated piezoresistive sensors have been developed in view of nanobiology and life science applications. For such applications, the experiments need usually to be performed under liquid conditions. The probe arrays have been fabricated by using silicon micromachining techniques and SOI wafers. For biological applications, when the cantilevers are immersed in electrically conductive buffer environments, the piezoresistive sensing elements have to be protected. For this purpose, the sensors were coated with a 50 nm thick silicon nitride film. The realized piezoresistive cantilevers had low spring constants between 0.1 and 0.5 N/m, well suited for biological applications. Parallel imaging using a 1 × 2 probe array was demonstrated by simultaneous imaging of a test sample in buffer solution.