Embodiments of the present disclosure provide a method including forming a gate electrode over a substrate, forming a ferroelectric layer over the gate electrode, forming a channel layer over the ferroelectric layer, forming a capping layer over the channel layer, wherein the capping layer includes one or more of CeOx, BeOx, InOx, GaOx, AlOx, SnOx, VOx, WOx, TiOx, ZrOx, NbOx, HfOx, SiOx, TaOx, a binary metal oxide based on any combination of the preceding metal oxides, or a ternary metal oxide based on any combination of the preceding metal oxides, annealing, after forming the capping layer, at a temperature less than 350° C., forming a dielectric layer over the capping layer, and forming a source contact and a drain contact in the dielectric layer.