Characterization of the field-effect addressable potentiometric sensor (FAPS)

The field-effect addressable potentiometric sensor (FAPS) is a surface pote ntial sensor with the option of high spatial resolution. It is based on the ability to control the resistance of field-effect channels in thin semicon ductor films with electrical potentials. Compared to arrays of standard fie ld-effect transistors (FET), the number of required leads is drastically re duced by arranging the field-effect channels and underlying gate electrodes in a grid structure. In order to investigate the practicability of the phy sical concept, a test structure was built by using the epitaxial lift-off t echnique. It was demonstrated that the concept of the FAPS can be put into practice. The frequency dependence of the test structure was analyzed exper imentally and theoretically. Ar a time resolution of 3 kHz, the potential s ensitivity was found to be better than 150 mu V. (C) 2000 Elsevier Science S.A. All rights reserved.