Performance Evaluation of Innovative Ion-Sensitive Field Effect Diode for pH Sensing

摘要： In this paper, we have successfully introduced and characterized an innovative ion sensitive device called “Ion sensitive field effect diode”, a completely new ion-sensitive sensor. In conventional ion-sensitive devices, electrolyte/insulator interface reactions produce a conductive channel between the drain and the source whereas in our proposed structure, a p-n junction forms and is responsible for the conductivity. Since it is for the first time that such device is proposed as an ion sensor, comprehensive characterizations have been performed based on our previously TCAD-based model which was developed to simulate electrolyte and electrolyte/insulator interface. Considering this reliable model, sensing parameters of pH sensors such as sensitivity and signal to noise ratio are investigated and evaluated. Meanwhile, an accurate model to approximate the noise behavior of the device is proposed. Moreover, the effect of Silicon active layer thickness and doping concentration on the sensitivity of the device have been studied. Results reveal that ion sensitive field effect diode can achieve sensitivity about 5 times higher than the Nernst limit and can be considered as a promising candidate toward accurate and more sensitive ion sensors and this new type of sensor deserves further attention and development.