The present invention relates to a FEMFET device with a semiconductor substrate and to at least one field effect transistor that is provided in the semiconductor substrate. The field effect transistor has a source area, a drain area, a channel area and a gate stack. The gate stack has at least one ferroelectric layer and at least one thin diffusion barrier layer being arranged between the lowest ferroelectric layer and the semiconductor substrate and being configured in such a way that an out-diffusion of the components of the ferroelectric layer into the semiconductor substrate is essentially prevented.