Determination by high-resolution X-ray diffraction of shape, size and lateral separation of buried empty channels in silicon-on-nothing architectures

Abstract

High‐resolution multi‐crystal X‐ray diffraction was employed to characterize silicon‐on‐nothing samples made by a one‐dimensional periodic planar array of buried empty channels. When the channels are normal to the scattering plane, under the constraint of lattice continuity from the perfect substrate to the surface, this periodic array gives rise to a well defined Fraunhofer diffraction in a scan crossing a selected reciprocal lattice point and normal to the reciprocal lattice vector (transverse or ω scan). In a longitudinal scan (ω/2θ scan crossing the reciprocal lattice point and parallel to the reciprocal lattice vector) interference fringes are observed. By analysis of the ω scan and numerical fit of the ω/2θ scan, the period of the buried empty channels and their shape, size and lateral gap were easily determined, thanks to the high‐resolution optics used for the measurements.

PCA-Based Analysis Applied to Germanium-On-Nothing: Revealing Buried Sub-Surface Structures and Analyzing Defects From Nanoscale Surface Topography

“…Interpolating from the SEM image PCA database only requires a single surface image, either AFM or SEM, reducing the acquisition period by a few orders with the use of the latter. Compared to exhaustive sub-surface inspection methodologies where acquisition durations are in the range of double to triple digit seconds [18][19][20][21][22] , acquisition of a single SEM image is instantaneous with the correct environmental setup. In the future, utilization of the correlation between SEM images and optical microscope images would take one step further, once again increasing the process simplicity by only requiring a much easily accessible microscopic image.…”

“…Since the cavity is buried under the covering layer, an accurate yet non-destructive inspection methodology is in demand to scrutinize the roughness and thickness of the self-assembled membrane to its definitive morphology requirements while preserving the subject for operation. Today, widely used thorough sub-surface imaging techniques include ultrasonic atomic force microscopy (UAFM) [18][19][20] , X-ray 21 and interferometry 22 . While such techniques provide 3-D profiles, they have their own limitations: UAFM has a limitation in subject thickness that could be inspected, interferometry cannot measure structures smaller than the wavelength of light used, and x-ray measurement resolution is larger than 100 nm 21 , not to mention the low-throughput of all these methodologies.…”

“…Today, widely used thorough sub-surface imaging techniques include ultrasonic atomic force microscopy (UAFM) [18][19][20] , X-ray 21 and interferometry 22 . While such techniques provide 3-D profiles, they have their own limitations: UAFM has a limitation in subject thickness that could be inspected, interferometry cannot measure structures smaller than the wavelength of light used, and x-ray measurement resolution is larger than 100 nm 21 , not to mention the low-throughput of all these methodologies. Therefore, a different approach must be considered to overcome the aforementioned intrinsic limitations.…”

Projected gradient methods for synchrotron radiation spectra distribution function reconstruction

“…It provides X-rays which are used for a wide range of analytical techniques. Since SR was first observed in 1947, it has been applied to many fields due to its good characteristics, and the theory of SR has been well understood and published [1][2][3]. One of the important characteristics is that the spectrum of SR source can be accurately calculated.…”

PCA-based sub-surface structure and defect analysis for germanium-on-nothing using nanoscale surface topography

“…S ince the cavity is buried under the covering layer, an accurate yet non-destructive inspection methodology is in demand to scrutinize the topography and thickness of the self-assembled membrane to its definitive morphology requirements while preserving the subject for operation. Today, widely used thorough sub-surface imaging techniques include ultrasonic atomic force microscopy (UAFM) 19 – 21 , X-ray 22 and interferometry 23 . While such techniques provide a stack of 2-D profiles, they have their own limitations: UAFM and most interferometries have a limitation in subject thickness that could be inspected, interferometry cannot measure structures smaller than the wavelength of light used, and X-ray measurement resolution is larger than 100 nm 22 , not to mention the low-throughput of all these methodologies, ranging between tens of seconds to minutes.…”