Abstract
A ferroelectric field effect transistor (FeFET) device includes a semiconductor substrate and a 3D transistor. The 3D transistor includes drain and source electrodes; a channel structure that includes a channel body and a gate dielectric layer; and a gate electrode that is disposed on the gate dielectric layer and that is electrically isolated from the drain and source electrodes. The channel body is disposed between and connected to the drain and source electrodes. The gate dielectric layer covers the channel body, is made of crystalline hafnium zirconium oxide, and has a thickness ranging from 2 nm to 5 nm. The FeFET device has an on/off current ratio that is greater than 5×104.