Fabrication and characterisation of Al gate n-metal–oxide–semiconductor field-effect transistor, on-chip fabricated with silicon nitride ion-sensitive field-effect transistor

摘要

In the present study, temperature drift analysis of metal-oxide-semiconductor field-effect transistor (MOSFET) is carried out using silicon nitride/SiO2 as dielectric film. An n-channel depletion-mode MOSFET was fabricated with silicon nitride ion-sensitive field-effect transistor (ISFET) on the same wafer. The study presents the fabrication, simulation and characterisation of MOSFET. The gate of the ISFET is stacked with silicon nitride/SiO2 sensing membrane that was deposited using low pressure chemical vapour deposition. Output and transfer characteristics of on-chip fabricated Al gate MOSFET were obtained in order to study the fabricated ISFET behaviour to be used as pH sensor. Silicon nitride is preferred over SiO2 sensing film/dielectric (in case of MOSFET) which has better sensitivity and low drift. Process and device simulations were performed using Silvaco® TCAD tool.