In-Situ Thin Film Composition Analysis via Zero-Thickness Ratio
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Solution Overview
Problem
Existing X-ray spectrometry techniques for determining the chemical composition of thin films are limited by complex interactions between electron beams and materials, leading to inaccurate measurements due to unknown parameters and multiple composition-dependent effects, requiring cumbersome calibrations and theoretical corrections, and are inefficient in generating X-rays within the film thickness.
Innovation Solution
A dynamic spectrometry method that acquires and analyzes multiple X-ray spectra during film growth, calculating a zero-film thickness ratio of elemental line intensities to determine chemical composition independently of film thickness, using a self-calibration routine and optimizing electron beam incidence angles for efficient X-ray generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional X-ray spectrometry techniques are used to determine chemical composition, then measurement can be performed, but measurement precision deteriorates due to complex electron-beam material interactions and unknown parameters
Solution Approach 1:
The patent applies preliminary action by acquiring X-ray spectra at multiple stages of film growth before the final composition is achieved. By measuring at different thicknesses during the deposition process, the system can extrapolate to determine the zero-thickness ratio of elemental line intensities, which directly relates to chemical composition without requiring complex corrections for electron-beam interactions.
Solution Approach 2:
The patent introduces a new dimension by analyzing the dependence of X-ray intensity ratios on film thickness. Instead of measuring composition at a single point, the system measures at multiple thickness values during growth and uses the thickness-dependent behavior to eliminate systematic errors, thereby improving measurement precision without increasing device complexity.
2Measurement precision
If multiple calibrations and theoretical corrections are applied to account for composition-dependent effects, then measurement precision may improve, but device complexity and difficulty of operation increase
Solution Approach 1:
The patent implements self-service by using the film itself during its growth process as the calibration reference. The system automatically acquires spectra at multiple stages and performs self-calibration by analyzing the change in intensity ratios with thickness, eliminating the need for external standard samples and complex manual calibration procedures.
Solution Approach 2:
The patent employs feedback by continuously monitoring the X-ray spectra during the deposition process and using the measured intensity changes to track film growth and composition evolution. This real-time feedback allows the system to compensate for composition-dependent effects dynamically, simplifying the overall operation while maintaining high measurement precision.
3Measurement precision
If X-ray spectra are acquired at multiple stages during film growth, then measurement precision improves by enabling zero-thickness ratio determination, but loss of time increases due to multiple measurements
Solution Approach 1:
The patent ensures continuity of useful action by performing spectral acquisitions continuously during the film deposition process without interrupting the growth. Multiple spectra are collected at different stages as the film thickens, allowing the system to determine composition through the thickness-dependent intensity ratio without requiring separate calibration measurements or stopping the deposition process.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables real-time, in-situ determination of thin film composition without requiring knowledge of film thickness or deposition rate, improving accuracy and efficiency by eliminating thickness-dependent corrections and using a single calibration sample, while allowing for real-time thickness monitoring and composition analysis of layered films.
Implementation Method 1
bombarding a predetermined area on the underlying structure with an electron beam incident on a surface of the underlying structure
Implementation Method 2
acquiring a 'zero-film' X-ray spectrum produced by the underlying structure upon exposure to the electron beams
Implementation Method 3
at least one X-ray sensor positioned at a second predetermined angle relative to the surface to collect X-rays emitted therefrom
Data Source
AI summary
System and method for determining the composition of deposited thin films by acquiring multiple sequential X-ray spectra for a film of interest during the deposition process as the film thickness increases, computing intensities of peaks found in the X-ray spectra corresponding to elements present in the film material, followed by computing, for each pair of elements, ratios of corresponding peak intensities, graphing the intensities and ratios against a parameter correlated to the film thickness, and applying a physically meaningful function to the graphed data for best fitting the data down to a ratio RA/B(0) for each pair of the elements for a virtual film of zero thickness. Elemental concentrations ratio for each pair of elements is subsequently computed as a product of RA/B(0) and a factor which is specific for the pair of elements, constant for the instrument as set up, and independent of elements concentrations, and of film thickness.