TCAD process simulation for light effect improvement of ion sensitive field effect transistor

The conventional open gate ISFET sensor is normally very sensitive to light exposure which influences the sensor characteristics. In this study, different process conditions of ISFET were simulated using SILVACO TCAD in order to find the right doping profile which minimizes light effect. Various channels doping levels for ISFET sensor have been analyzed. Comparison with SRP samples was done in order to ensure the accuracy of the simulation output. Based on simulation results, the ISFETs were then fabricated and tested under the same intensities of light exposure and ambient temperatures. It shows that ISFET which underwent double PWELL implant and with deeper junction depth experiences lower light effect. This paper will discuss on how doping profiles affect ISFET performance with respect to light effect.