
The tremendous impact of SEM based EBSD techniques over the past 20 years
demonstrates the value of mapped crystallographic information , which provides
insight on processing history, structure-property relationships, interfaces
and phase structure with resolution range from 50-10 nm. The development of
TEM based- automated crystallographic mapping techniques (ASTAR) in
combination with precession electron diffraction (PED) [1,2] has pushed the
resolution limit at 1 nm scale. Combination of ASTAR 4D scanning
orientation/phase map technique with advanced TEM Cs corrected /FEG
instruments over the last 10 years allowed study of various materials such as
metals /alloys, minerals , semiconductors and even organic materials. The
combination of PED with scanning nanodiffraction enables to measure accurately
strain (precision up to 0.01%) with 1-3 nm resolution at semiconductor
devices.
Although all work done on phase and orientation maps has been limited with
known crystal phase materials (unit cell and atomic coordinates) there are
many problems where we deal with unknown phases. ADT 3D (automatic diffraction
tomography combined with precession diffraction) allows 3D reciprocal space
reconstruction from tilted ED series (usually every 1 deg) from nanocrystals
as small as 20 nm. This way unit cell & structure determination can be
obtained by measuring ED intensities from unknown structures [3] where atomic
positions can be located with picometer level precision via dynamical
refinements [4].
The recent application of e-PDF (electron Pair Distribution Function)
techniques [5] allows to analyse at local scale Electron Diffraction (ED)
patterns even from amorphous materials. e-PDF technique allows to analyse
interatomic distances , bonding and possible short/large scale order of
nanocrystalline /amorphous materials at nm scale , enabling to monitor in situ
solid state reactions, structure of glassy materials, layered thin films
quality and amorphous/ re-crystallization studies in semiconductor devices.
We will present various application examples of PED combination with
orientation imaging, ADT 3D and e-PDF studies for studies of materials from
characterization of colour pigments in Ancient Roman mosaic glass to high tech
semiconductor devices.
[1] Vincent R & Midgley PA (1994) Ultramicroscopy 53, 271-282
[2] Rauch E.F,Portillo J, Nicolopoulos S. Bultreys D. Rouvimov S. Moeck P.
(2010) Zeit fur Krist, 225,103-109
[3] Kolb U, Gorelik T , Kubel C, Otten M, Hubert D (2007) Utramicroscopy ,
107, 507-513
[4] Mugnaioli E., Gemmi M, Merlini M , Gregorkiewitz (2016) Acta Cryst B72 ,
893-903
[5] T.Egami, S.Billinge Underneath the Bragg Peaks Pergamon vol.16
**Host** : A. Chuvilin