DEVELOPMENT OF MATERIALS INTEGRATION STRATEGIES FOR ELECTROCERAMIC FILM-BASED DEVICES VIA COMPLEMENTARY IN SITU AND EX SITU STUDIES OF FILM GROWTH AND INTERFACE PROCESSES

摘要

We review our studies of film growth and interface processes performed using complementary in situ and ex situ characterization techniques that provide valuable information critical to the development of materials integration strategies for the fabrication of electroceramic film-based devices. Specifically, we review our work performed using in situ time-of-flight ion scattering and recoil spectroscopy (TOF-ISARS)/X-ray photoemission spectroscopy (XPS)/spectroscopic ellipsometry (SE), in conjunction with ex situ TEM and other techniques to study film growth and interface processes critical to the fabrication of non-volatile ferroelectric memories (NVFRAMs), dynamic random access memories (DRAMs), and high frequency devices based on high-K thin films. TOF-ISARS involves three distinct but closely related experimental methods, namely: ion scattering spectroscopy, direct recoil spectroscopy and mass spectroscopy of recoiled ions, which provide monolayer-specific information on film growth and surface segregation processes. Spectroscopic Ellipsometry enables investigation of buried interfaces. XPS provides valuable information on the chemistry of surface and interfaces. Specifically, we discuss: a) studies of oxidation of Ti-Al layers and synthesis and properties of La_(0.5)Sr_(0.5)CoO_9/Ti-Al heterostructured layers for integration of PZT capacitors with Si substrates, and b) studies of BaSr_xTi_(1-x)O_3 layer integration with Si substrates relevant to DRAMs, high frequency devices and high-K gate oxides for integrated circuits. This review shows the power of combined in situ/ex situ analytical techniques to provide valuable information for material integration strategies for electroceramic thin film-based devices.