Si technology based microinductive devices for biodetection applications

This work presents the design and fabrication of inductive devices integrated in Si technology aimed at high sensitivity biodetection applications. The sensing principle is based on the changes of the coil inductance due to the presence of magnetic particles in the active region of the device. These particles act as markers of the biological molecule to be detected. For the simulation of the devices, a very simple finite elements model has been developed. To increase the device sensibility to the presence of the magnetic particles, a magnetic layer has been locally deposited on the back of the substrate in the region of the coils. The analysis of these devices has shown their ability to detect a minimum amount of 110 magnetic particles fixed on an 0.8 mm2 active area, which gives an estimation of the detection limit of the devices of about 4 × 10−14 M. This corroborates the potential of the proposed microinductive devices for very high sensitivity detection of biological molecules.