Surface potential imaging in oxide-nitride-oxide-silicon structure using a field effect transistor cantilever

To verify the application of the new atomic force microscopy (AFM) cantilever with field effect transistor (FET) structure, the images of the surface potential in the silicon dioxide (SiO₂)-silicon nitride (SiN)-silicon dioxide-silicon (ONOS) structure were examined in this study. The images were obtained under the continuous application of dc bias and short time in the contact-mode AFM. And the FET cantilever was not affected by external parameters, such as moisture and temperature. The duration of the charge confinement in this study was shorter than those in previous studies because the SiN layer was very thin, measuring less than 5 nm. The retention time of the surface potential in the ONOS structure was achieved above 2 h at high voltage applied to the gate. The retention time, however, was about 1 h at low-voltage conditions.