Erbium oxide as pH-sensing membranes in extended gate field effect transistors

The Erbium oxide (Er₂O₃) sensing membrane was deposited on polysilicon and applied in the extendedgate field-effect transistor (EGFET) for pH detection. The device performance was improved with proper postannealing RTA treatment. To evaluate the sensor performance, pH sensitivity, hysteresis effects, and drift rate were measured to find the optimal annealing condition. XRD material analysis further confirms that the membrane annealed at 800 °C could achieve high sensitivity, high linearity, low hysteresis voltage, and low drift ratio due to reinforcements of crystalline structures. The high-k Erbium oxide sensing membrane in the EGFET is promising for future generation of bio-medical device applications.