SnO2Separative Structure Extended Gate H+-Ion Sensitive Field Effect Transistor by the Sol–Gel Technology and the Readout Circuit Developed by Source Follower

In this study, the tin oxide membrane, fabricated by the sol–gel technology, was used as the pH-sensing layer of the extended gate H + -ion sensitive field effect transistor (EGFET) device. The sensing membrane was deposited on the silicon substrate. The cost of fabricating the EGFET device by the sol–gel technology is lower than by the other methods. The sensitivity of the sol–gel prepared tin oxide separative structure EGFET device is about 57.63 mV/pH in the range of pH1 to pH9. The readout circuit of the tin oxide EGFET was developed by the source follower.