Application of convergent beam electron diffraction to two-dimensional strain mapping in silicon devices

Abstract

A method of obtaining quantitative two-dimensional (2D) maps of strain by the convergent beam electron diffraction technique in a transmission electron microscope is described. It is based on the automatic acquisition of a series of diffraction patterns generated from digital rastering the electron spot in a matrix of points within a selected area of the sample. These patterns are stored in a database and the corresponding strain tensor at each point is calculated, thus yielding a 2D strain map. An example of application of this method to cross-sectioned cells fabricated for the 0.15 μm technology of flash memories is reported.

Strain measurements by convergent-beam electron diffraction: The importance of stress relaxation in lamella preparations

“…2 In particular, the CBED method has been the subject of the European project STREAM. 3,4 However, the validity of the analysis is limited to regions where deformation is faint, which in our case turn out to be regions situated at a distance of about 200 nm from the interfaces of interest and, moreover, the stress relaxation of the thin TEM lamella is considered negligible due to its relatively large thickness ͑Ͼ100 nm͒. But stress relaxation in TEM lamella is a wellknown phenomenon and has to be included in the analysis of data coming from many TEM techniques like high resolution electron microscopy, 5,6 large angle convergent beam electron diffraction, 7,8 or two-beam images.…”

Elastic relaxation in an ultrathin strained silicon-on-insulator structure

“…Recent progress in probing the strain distribution in nanostructures includes utilizing Raman spectroscopy, 7,8 transmission electron microscopy (TEM) based techniques, 9 and x-ray diffraction based techniques, such as microbeam x-ray diffraction, 10 high resolution x-ray diffraction, 11,12 and grazing incidence x-ray diffraction (GIXRD). 13 Raman spectroscopy provides a fairly good spatial resolution and does not require a specific sample preparation, but it is limited to bare Si structures as the top metallic layer in the device prohibits the laser penetration.…”

Simulation and Characterization of the Strain Induced by an Original "Embedded Buried Nitride" Technique

“…Grazing incidence (α i =0.12°) and emergence angles (α f =0.24°) close to the critical angles of total reflection allow measuring the diffraction of the (220) and (2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20) planes perpendicular to the surface (see inset of Figure 3a) of the top SOI layer. Larger grazing angles (α i =0.3°, α f =0.6°) are used to go through the amorphous nitride layer, in the substrate.…”