Performance and Investigation Analysis of Extended Source Vertical Tunnel Field Effect Transistor‐Based High‐Sensitivity pH Sensor

This article presents an innovative extended source structure for vertical tunnel field effect transistor as a pH sensor for detecting bio‐electrolyte. In this structure, the source has been extended inside the channel to improve the sensitivity. The optimal extended source inside the channel is S h = 30 nm, which shows the higher drain current and drain current sensitivity. Current sensitivity has also been examined for the proposed structure with variations in pH value. An electrolyte model and site binding model have also been developed for surface potential in order to better understand device physics as a pH sensor, as pH changes directly impact surface charge density, thus detecting small changes. In addition, the pH sensor's response to variations in extended sources has been investigated. Additionally, the proposed pH sensor has a voltage sensitivity of about 100 mV pH −1 , exceeding Nernst's limit.