Basically, there are two different reasons for including anisotropy into a TCAD tool for ferroelectric materials. First, the ferroelectric materials show strong anisotropy and inclusion of it will meet the physics in an accurate way, thus allowing a deeper insight into the properties inside the device. Second, the ever decreasing device geometries and the thin film thicknesses lead to a regime where anisotropy cannot be neglected.
Satisfying this generic approach, the new algorithm is capable of dealing with materials with one or two anisotropy axes with arbitrary orientations. For the first basic steps of anisotropy simulation all dipoles are assumed to be oriented in one of the anisotropy axes.
Since rotation processes which might occur at high fields are neglected, the dipoles have to switch between the anisotropy axes. Furthermore it is presumed that the number of dipoles and domains is still big enough that they do not influence the macroscopic field properties.