Atomic Layer deposition of 2D and 3D standards for quantitative synchrotron-based composition and structural analysis methods

TL;DR

This paper demonstrates that Atomic Layer Deposition can produce highly uniform 2D and 3D standards, improving the accuracy and reproducibility of synchrotron-based compositional and structural analysis methods.

Contribution

It introduces ALD as a scalable technique for creating homogeneous standards to replace traditional NIST SRMs in synchrotron analysis.

Findings

ALD produces uniform films over hundreds of microns to nanometers.

ALD standards improve measurement reproducibility.

The methods include Rutherford Backscattering, X-ray Reflectivity, and more.

Abstract

The use of Standard Reference Materials (SRM) from the National Institute of Standards and Technology (NIST) for quantitative analysis of chemical composition using Synchrotron based X-Ray Florescence (SR-XRF) and Scanning Transmission X-Ray Microscopy (STXM) is common. These standards however can suffer from inhomogeneity in chemical composition and thickness and often require further calculations, based on sample mounting and detector geometry, to obtain quantitative results. These inhomogeneities negatively impact the reproducibility of the measurements and the quantitative measure itself. Atomic Layer Deposition (ALD) is an inexpensive, scalable deposition technique known for producing uniform, conformal films of a wide range of compounds on nearly any substrate material. These traits make it an ideal deposition method for producing films to replace the NIST standards and create SRM on a wide range of relevant 2D and 3D substrates. Utilizing Rutherford Backscattering, X-ray Reflectivity, Quartz crystal microbalance, STXM, and SR-XRF we show that ALD is capable of producing films that are homogenous over scales ranging from 100's of microns to nms