Kelvin Force Probe Microscopy of Ferroelectric Si:HfO2

Thursday, 5 October 2017: 12:00
Chesapeake D (Gaylord National Resort and Convention Center)
D. Marinskiy (Semilab SDI), P. Polakowski (Fraunhofer IPMS-CNT), J. Lagowski, M. Wilson, P. Edelman (Semilab SDI), and J. Müller (Fraunhofer Institute for Photonic Microsystems IPMS)
Since the demonstration of the ferroelectric properties in hafnium based oxides in 2011 there is large interest to such films for ferroelectric FET, memory, and other applications. Engineering of ferroelectricity in HfO2 relies on doping and annealing. For Si-doped HfO2films, a top metal electrode capping layer is deposited prior to annealing which is shown to cause ferroelectric behavior.

In this paper we present results of non-contact corona-Kelvin characterization of poling phenomena for ferroelectric Si:HfO2 thin films. Measurements were performed on free dielectric surfaces. The method uses corona charging and Kelvin force probe measurements. Corona charging pulses are analogous to voltage biasing, except that no top electrode is needed. Corona charging enables biasing the Si:HfO2to a near coercive field where onset of poling occurs. Mapping of the surface voltage with a small diameter Kelvin force probe allows to quantify poling phenomena, its uniformity and degradation during repetitive switching (Fig. 1).

These results are of importance for fundamental understanding of switching mechanisms of ferroelectric Si:HfO2 films.