FET-Addressed Biosensor Arrays

Besides the biomolecular probes and the packaging components, the electronic components of a fully integrated biosensor array can be divided into three categories transducer, array addressing circuit, and measurement unit. As the most widely used microelectronic devices, FETs play an important role in all these three categories. 

Two possible architectures for TFT-addressed biosensor arrays are illustrated in Figs. 6.10 and 6.11. For potentiometric sensing, the biosensing pad is connected to the gate of the TFT (see Fig. 6.10), which acts as the transducer. A dummy transistor, where no biomolecular interaction occurs, can be used for differential measurements [45]. For current detection, the sensing pad needs to be connected to the source or the drain of the TFT as shown in Fig. 6.11. 

As the biomolecular interaction delivers a very weak electronic signal, integrated amplification and noise canceling are often 

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