scholarly journals Compressive nano-FTIR chemical mapping

Author(s):  
Gerd Wuebbeler ◽  
Manuel Marschall ◽  
Eckart Rühl ◽  
Bernd Kaestner ◽  
Clemens Elster

Abstract Nano-Fourier-transform infrared spectroscopy (nano-FTIR) combines infrared spectroscopy with scanning probe microscopy (SPM) techniques and enables spectroscopic imaging of molecular and electronic properties of matter at nanometer spatial resolution. The spectroscopic imaging can be used to derive chemical mappings, i.e., the spatial distribution of concentrations of the species contained in a given sample. However, due to the sequential scanning principle underlying SPM, recording the complete spectrum over a large spatial area leads to long measurement times. Furthermore, the acquired spectrum often contains additional signals from species and lineshape effects that are not explicitly accounted for. A compressive chemical mapping approach is proposed for undersampled nano-FTIR data that utilizes sparsity of these additional signals in the spectral domain. The approach combines a projection technique with standard compressed sensing, followed by a spatially regularized regression. Using real nano-FTIR measurements superimposed by simulated interferograms representing the chemical mapping of the contained species, it is demonstrated that the proposed procedure performs well even in cases in which the simulated interferograms and the sparse additional signals exhibit a strong spectral overlap.

Nanoscale ◽  
2021 ◽  
Author(s):  
wei Lv ◽  
hanchao Teng ◽  
chenchen Wu ◽  
Xiaotao Zhang ◽  
Xiangdong Guo ◽  
...  

Nanoscale Fourier transforms infrared spectroscopy (nano-FTIR) based on scanning probe microscopy enables identification of chemical composition and structure of surface species with a high spatial resolution (~10 nm), which is...


Author(s):  
N.J. Tao ◽  
J.A. DeRose ◽  
P.I. Oden ◽  
S.M. Lindsay

Clemmer and Beebe have pointed out that surface structures on graphite substrates can be misinterpreted as biopolymer images in STM experiments. We have been using electrochemical methods to react DNA fragments onto gold electrodes for STM and AFM imaging. The adsorbates produced in this way are only homogeneous in special circumstances. Searching an inhomogeneous substrate for ‘desired’ images limits the value of the data. Here, we report on a reversible method for imaging adsorbates. The molecules can be lifted onto and off the substrate during imaging. This leaves no doubt about the validity or statistical significance of the images. Furthermore, environmental effects (such as changes in electrolyte or surface charge) can be investigated easily.


Author(s):  
Kevin M. Shakesheff ◽  
Martyn C. Davies ◽  
Clive J. Roberts ◽  
Saul J. B. Tendler ◽  
Philip M. Williams

Author(s):  
Benedict Drevniok ◽  
St. John Dixon-Warren ◽  
Oskar Amster ◽  
Stuart L Friedman ◽  
Yongliang Yang

Abstract Scanning microwave impedance microscopy was used to analyze a CMOS image sensor sample to reveal details of the dopant profiling in planar and cross-sectional samples. Sitespecific capacitance-voltage spectroscopy was performed on different regions of the samples.


Author(s):  
Swaminathan Subramanian ◽  
Khiem Ly ◽  
Tony Chrastecky

Abstract Visualization of dopant related anomalies in integrated circuits is extremely challenging. Cleaving of the die may not be possible in practical failure analysis situations that require extensive electrical fault isolation, where the failing die can be submitted of scanning probe microscopy analysis in various states such as partially depackaged die, backside thinned die, and so on. In advanced technologies, the circuit orientation in the wafer may not align with preferred crystallographic direction for cleaving the silicon or other substrates. In order to overcome these issues, a focused ion beam lift-out based approach for site-specific cross-section sample preparation is developed in this work. A directional mechanical polishing procedure to produce smooth damage-free surface for junction profiling is also implemented. Two failure analysis applications of the sample preparation method to visualize junction anomalies using scanning microwave microscopy are also discussed.


Author(s):  
Tsan-Chang Chuang ◽  
Cha-Ming Shen ◽  
Shi-Chen Lin ◽  
Chen-May Huang ◽  
Jin-Hong Chou ◽  
...  

Abstract Scanning capacitance microscopy (SCM) is a 2-D carrier and/or dopant concentration profiling technique under development that utilizes the excellent spatial resolution of scanning probe microscopy. However, PV-SCM has limited capability to achieve the goal due to inherent "plane" trait. On top of that, deeper concentration profile just like deep N-well is also one of restrictions to use. For representing above contents more clearly, this paper presents a few cases that demonstrate the alternated and optimized application of PV-SCM and X-SCM. The case studies concern Joint Test Action Group failure and stand-by failure. These cases illustrate that the correct selection from either plane-view or cross-sectional SCM analysis according to the surrounding of defect could help to exactly and rapidly diagnose the failure mechanism. Alternating and optimizing PV-SCM and X-SCM techniques to navigate various implant issue could provide corrective actions that suit local circumstance of defects and identify the root cause.


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