Nanostructures

Cadmium Telluride (CdTe) is a semiconductor with a wide range of applications extending from gamma or x-ray detectors to solar cells. Due to the heterogeneity of the CdTe compound, the planarity of the focused ion beam (FIB) etched structures is uneven and requires FIB milling process optimization.

LiteScope benefits:

• Surface modification using FIB/GIS techniques can be performed directly on a tilted LiteScope inside SEM, which is crucial for sensitive samples prone to oxidation.
• Immediate assessment of the modified surface profile and process quality control.
• FIB milling process optimization by sputtering rate and roughness estimation.

Published with courtesy: Ondrej Sik and Martin Konecny, CEITEC BUT, Czechia, and Veronika Hegrová, NenoVision, Czechia

Microcrystalline silicon is a silicon film where the sizes of the silicon crystals are in the order of dozens of nanometers. The μc-Si: H thin films are suitable for various devices, such as TFTs, thin solar cells with larger IR absorption, and more stable against sun radiation. LiteScope supports conductive AFM (cAFM) analysis inside SEM, which helps to easily localize particular structures and to assess conductivity mapping with nanometer precision.

LiteScope benefits:

• AFM-in-SEM enables complex correlative imaging and analysis
  • SEM: material contrast and fast nanostructure localization
  • c-AFM: topography and conductivity map

Published with courtesy: RNDr. Antonín Fejfar, Czech Academy of Science, Czechia

Metastable Fe78Ni22 thin film grown on a copper substrate has the potential for magnetic patterning - it is paramagnetic at room temperature but can be transformed by the FIB irradiation into a ferromagnetic material. Simultaneous measurement of AFM and SEM signals revealed that the crystallography transformation is accompanied by a topography change.

LiteScope benefits:

• Surface modification using FIB/GIS techniques can be performed directly on a tilted LiteScope inside SEM, which is crucial for sensitive samples prone to oxidation.
• Immediate assessment of the modified surface profile and process quality control.

Published with courtesy: Lukas Flajsman, CEITEC BUT, Czechia

Due to miniaturization, failure analysis of advanced integrated circuits is possible only by local-focused ion beam (FIB) delayering. Planarity and roughness of delayered surfaces need to be analyzed.

LiteScope benefits:

• Precise identification of a particular layer, excellent planarity of FIB milled structures with minimal sample damage.
• 3D reconstruction: in-situ assessment of topography and roughness of milled structure.

Gallium Nitride (GaN) is a very promising material for electronic and optoelectronic applications, however, a variety of dislocations can occur at the different material interface, which leads to low-quality films.

LiteScope benefits:

• Various defects can be localized and characterized only by the CPEM view, combining AFM, SEM, and EBIC (Electron Beam Induced Current).
• CPEM allows for a direct comparison between surface topography, electrical activity, and sample surface chemistry.

Published with courtesy: Roman Gröger, IPM CAS, Czechia

Time-of-Flight Secondary Ion Mass Spectrometry (ToF-SIMS) provides elemental, chemical state, and molecular information from surfaces of solid materials. The alloy with lithium and aluminum particles is used for the sensitivity verification of SIMS detectors for light elements.

Correlation of SEM ToF-SIMS with AFM provides the missing sample topography and allows the calculation of e.g. sputter rates to optimize the process, which is crucial especially for  heterogeneous materials.

LiteScope benefits:

• Fast and accurate localization of surface structures.
• Initial sample topography assessment and  3D CPEM visualization of the sputtered volume containing SEM material contrast.