Studies of ferroelectric heterostructure thin films, interfaces, and device-211 related processes via in situ analytical techniques

摘要

The science and technology of ferroelectric thin films has experienced an211u001eexplosive development during the last ten years. Low-density non-volatile 211u001eferroelectric random access memories (NVFRAMS) are now incorporated in commercial 211u001eproducts such as 'smart cards', while high permittivity capacitors are 211u001eincorporated in cellular phones. However, substantial work is still needed to 211u001edevelop materials integration strategies for high-density memories. We have 211u001edemonstrated that the implementation of complementary in situ characterization 211u001etechniques is critical to understand film growth and device processes relevant to 211u001edevice development. We are using uniquely integrated time of flight ion 211u001escattering and recoil spectroscopy (TOF-ISARS) and spectroscopic ellipsometry 211u001e(SE) techniques to perform in situ, real-time studies of film growth processes in 211u001ethe high background gas pressure required to growth ferroelectric thin films. TOF-211u001eISARS provides information on surface processes, while SE permits the 211u001einvestigation of buried interfaces as they are being formed. Recent studies on 211u001eSrBi(sub 2)Ta(sub 2)O(sub 9) (SBT) and Ba(sub x)Sr(sub 1(minus)x)TiO(sub 3) (BST) 211u001efilm growth and interface processes are discussed. Direct imaging of 211u001eferroelectric domains under applied electric fields can provide valuable 211u001einformation to understand domain dynamics in ferroelectric films. We discuss 211u001eresults of piezoresponse scanning force microscopy (SFM) imaging for nanoscale 211u001estudies of polarization reversal and retention loss in Pb(Zr(sub x)Ti(sub 211u001e1(minus)x))O(sub 3) (PZT)-based capacitors. Another powerful technique suitable 211u001efor in situ, real-time characterization of film growth processes and 211u001eferroelectric film-based device operation is based on synchrotrons X-ray 211u001escattering, which is currently being implemented at Argonne National Laboratory.