In situ, real-time analysis of the growth of ferroelectric and conductive oxide heterostructures by a new time-of-flight pulsed ion beam surface analysis technique

A new time-of-flight ion scattering and recoil spectroscopy (TOF-ISARS) technique has been developed and is now used to perform in situ, real-time analysis of ferroelectric and conductive oxide layers during growth. Initial results presented here show various major effects, namely: (a) RuO₂ films on MgO substrates appear to be terminated in O atoms on the top layer located in between Ru atoms lying in the layer underneath (This effect may have major implications for the explanation of the elimination of polarization fatigue demonstrated for RuO₂/PZT/RuO₂ heterostructure capacitors); (b) deposition of a Ru monolayer on top of a Pb monolayer results in surface segregation of Pb until a complete Pb layer develops over the Ru monolayer; and (c) a Pb/Zr/Ti layered structure yields a top Pb layer with first evidence of the existence of Pb vacancies, which also may have major implications in relation to the electrical characteristics of PZT-based capacitors.