US Patent 7198959 Process for fabrication of a ferrocapacitor

In a process for fabricating a ferrocapacitor comprising providing ferroelectric PZT elements over an Al2O3 layer, the Al2O3 layer is covered with a seed layer comprising layers of PZT and TiO2. Then a thicker layer of PZT is formed over the seed layer and crystallized. By this process, the crystallinity of the thick PZT layer is much improved, and its orientation is improved to be in the (111) direction. Furthermore, the seed layer reduces downward diffraction of Pb from the thick PZT layer, such as through the Al2O3 into a TEOS structure beneath.