Threshold voltage adjustment of ferroelectric-gate field effect transistors by ion implantation

The electric properties of ferroelectric-gate field-effect transistors (FeFETs) are investigated by using ion implantation. The doping concentration increases from 4 × 10 14 to 1 × 10 18 cm −3 , and the corresponding threshold voltages of the FeFETs shift from 0.18 to −1.65 V, and from 0.98 to −0.54 V for the left- and right-side threshold voltages, respectively, which can be fitted to a theoretical result. The retention is measured at different doping concentrations for about 2 days, and all exhibit good retention characteristic. The results show that ion implantation is an effective method to adjust the threshold voltage in FeFET technology.