AVS 59th Annual International Symposium and Exhibition
    Nanometer-scale Science and Technology Thursday Sessions
       Session NS-ThM

Paper NS-ThM10
Spectroscopic Imaging of Silicon-Hafnia Interfaces

Thursday, November 1, 2012, 11:00 am, Room 12

Session: Nanoscale Imaging and Microscopy
Presenter: C. Guedj, CEA, LETI, MINATEC Campus, France
Authors: C. Guedj, CEA, LETI, MINATEC Campus, France
H. Grampeix, CEA, LETI, MINATEC Campus, France
C. Licitra, CEA, LETI, MINATEC Campus, France
E. Martinez, CEA, LETI, MINATEC Campus, France
Correspondent: Click to Email
New behavior and phenomena can emerge at oxide interfaces, and the nanocharacterization of these properties is a real challenge for the semiconductor industry [i] . To replace the conventional SiO2 insulator, hafnium-based oxides have been introduced [ii],[iii] into advanced CMOS devices such as MOSFETs or memories [iv], but the nanometric control of their interfacial properties still remains a critical issue. For further industrial implementation of these oxides, it is necessary to obtain sufficiently high dielectric constants and bandgaps, good thermal stability on silicon, good scalability and sufficient reliability [v] at a reasonable cost. In this presentation, we have performed spectroscopic imaging of silicon-hafnia interfaces using energy filtered high-resolution transmission electron microscopy and valence electron energy loss spectroscopy (HRTEM-VEELS), coupled with X-Ray photoelectron spectroscopy (XPS), Reflection energy loss spectroscopy (REELS), UV photoelectron spectroscopy (UPS) and spectroscopic ellipsometry. Optical absorptions and bandgap profiles across the interface are obtained and novel ordering effects like axiotaxy are locally observed. An atomic-scale modelling is proposed, and the consequences in terms of device performances are detailed.
[i] http://www.itrs.net/Links/2011ITRS/2011Chapters/2011Metrology.pdf
[ii] R.M. Wallace and G.D. Wilk, Crit. Rev. Solid State Mater. Sci. 28, 213 (2003)
[iii] M.H. Cho et al., Appl. Phys. Lett. 81, 1071 (2002)
[iv] B.Govoreanu et al., proc. IEEE IEDM , p 729 (2011)
[v] J. Robertson, Solid-state electron., Vol. 49, p 283-293 (2005)