Variability analysis of ferroelectric FETs in program operation using low-frequency noise spectroscopy

We investigate the variability of a ferroelectric FET (FEFET) in program operation using low-frequency noise (LFN) spectroscopy. Contrary to the previous report, LFN characteristics of FEFETs differ significantly depending on the program [low threshold voltage (Vth)] or erase state [high Vth)] [Shin et al., IEEE Electron Device Lett. 43, 13 (2022)]. Furthermore, the 1/f noise variation of the FEFETs is much larger in the program state than that in the erase state. It is revealed that the change in the number of electrons trapped at the FE/dielectric interface and oxygen vacancy in each program operation is the main reason for the variability of the FEFET in program operation. The variation stemming from the change in the number of trapped charges is significantly worsened when the channel area is scaled down.