Integrated ferroelectric thin films for electronic devices of the future

Worldwide the incorporation of ferroelectric thin films in the future generations of DRAMs and in memory devices in which the remnant polarization is used to achieve a non volatile data storage (FeRAMs) is under intense investigation. Currently all the leading companies in the memory chip business are running programs to integrate the new materials into their semiconductor fabrication. On a smaller scale, but also expected as rapidly growing in the near future are thin film pyroelectric detector arrays for the presence and motion detection of persons in a wide range of applications. Currently three materials are favored for these three applications: For the storage capacitor of the DRAMs (Ba,Sr)TiO3, for the FeRAMs SrBi2Ta2O9 and for the pyroelectric detector arrays lead based perovskites like PbTiO3 and Pb(Zr, Ti)O3(PZT). The focus of this paper is thin film pyroelectric detector arrays on silicon substrates using PZT thin films as pyroelectric material. A planar multi-target approach was used to deposit PZT films on Pt electrodes at very low substrate temperatures of about 450 degrees Celsius. These films have been used for fabricating a two dimensional 11 by 6 pixel pyroelectric detector array for motion detection. The array pixels with a sensitive area of 280 by 280 micrometer2 have a noise equivalent power NEP of less than 0.7 nW at 1 Hz.