New Methods For Isfet Light Sensitivity Reduction

Three novel ideas for reduction of ISFET light sensitivity are proposed on the basis of simulation. Verification is provided by measurements on processed devices concept is based on shielding the surroundings of the ISFET by polysilicon leads with simultaneous size reduction, the second one utilizes proton irradiation in order to locally reduce the minority carrier lifetime, and the third one closes the ISFET into a p-well to be shielded from optically generated carriers. All the devices were processed by means of a conventional p-well process. Theoretical investigations involved physically- based 2-D device simulation by use of ATLAS simulator with package called LUMINOUS.