Fabrication and characterization of Al gate n-MOSFET, on-chip fabricated with Si3N4 ISFET

This paper reports the fabrication of n-type MOSFET using Si₃N₄ as dielectric on the same wafer as ISFET for ISFET characterization. The paper presents the fabrication, simulation and characterization of metal-oxide field-effect transistor (MOSFET). The gate of the ISFET is stacked with Si₃N₄ sensing membrane layer that has been deposited using LPCVD system to cover the gate area. Output and transfer characteristics of on-chip fabricated MOSFET are obtained and measured in order to study the fabricated ISFET behavior to be used as pH sensor. Silicon nitride is preferred over silicon dioxide sensing film/dielectric (in case of MOSFET) which has better sensitivity and low drift. Process simulations were performed using Silvaco^® TCAD tool.