Advanced Raman Spectroscopy Using Nanofocusing of Light

Abstract

Raman spectroscopy is uniquely sensitive to crucial material properties like stress and composition, but is inherently diffraction-limited, impeding its application potential in nanostructured devices. Under correct polarization conditions, the Raman response from a periodic array of fins is dramatically enhanced inside the semiconductor material, re-enabling fast and non-destructive optical characterization of deep-subwavelength semiconductor patterns. In this paper, it is shown that the effect is not limited to the material system where it was first observed, and results of nanofocused Raman spectroscopy in a variety of semiconductor materials are presented. The authors illustrate and discuss how the universality of the enhancement creates a unique potential for non-invasive and rapid stress and composition measurements at the nanoscale.

Rutherford backscattering spectrometry analysis of InGaAs nanostructures

“…By exploiting the underlying physics of the characterization methods, it has been possible to isolate the information of the devices from the surrounding matrix. The study of embedded nanostructures using ensemble measurements has already been reported for small-angle x-ray scattering, for grazing-incidence x-ray fluorescence, 7 for medium energy ion scattering, 8 for Raman spectroscopy, 9 and for secondary ion mass spectrometry. 10 In the present work, we will present the developments required to extend this approach toward Rutherford backscattering spectrometry (RBS).…”

Taming the Distribution of Light in Gate-All-Around Semiconductor Devices

“…stress to be measured in nanometer-scale fin field-effect transistors (finFETs) with Raman spectroscopy. 6,9,10 However, these previous studies were limited to single arrays of lines and consequently could not be applied after the replacement gate processing of modern GAA transistors, when two perpendicular gratings are processed on top of each other with the top grating being made of 150−200 nm thick amorphous Si lines. 11,12 The present paper extends our previous studies and demonstrates that the nanofocusing effect is also of application in systems constituted of two perpendicular gratings.…”

“…The strongly enhanced signal-to-noise ratio allowed e.g. stress to be measured in nanometer-scale fin field-effect transistors (finFETs) with Raman spectroscopy. ,, However, these previous studies were limited to single arrays of lines and consequently could not be applied after the replacement gate processing of modern GAA transistors, when two perpendicular gratings are processed on top of each other with the top grating being made of 150–200 nm thick amorphous Si lines. , …”

“…This paper distinguishes itself from our past work − by the extra complexity of the structures of interest. The gate-all-around (GAA) samples used in this Letter are so-called forksheet devices , shown in Figure .…”

Quantification of area-selective deposition on nanometer-scale patterns using Rutherford backscattering spectrometry

“…Recently, a new group of techniques has emerged which are based on the principle of the ensemble measurement. This is the simultaneous measurement of a large ensemble of structures and leads to an enhanced sensitivity [8][9][10][11][12][13][14][15] . It is enabled by the excellent uniformity of the nano-scale patterns produced by semiconductor manufacturing [16][17][18] , characterized by a standard deviation on the size of the nanostructures of the order of 1 nm.…”