Electron Spectroscopy Depth Profiling with Laser Ablation

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Solution Overview

Problem

Existing electron spectroscopy methods, such as XPS and AES, face issues with sample damage and preferential sputtering, particularly in ion beam-sensitive materials, and have low material removal rates, making depth profiling beyond 5 microns impractical.

Innovation Solution

The use of laser pulses in combination with electron spectroscopy techniques like XPS and AES for material ablation, allowing for improved chemical composition analysis and increased depth profiling by ablating material with femtosecond laser pulses, and adjusting parameters based on sample composition.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of substance

If ion beam sputtering is used for material removal in XPS/AES depth profiling, then material can be removed from the surface, but sample damage and preferential sputtering occur particularly in ion beam-sensitive materials

Engineering Contradiction:

Improvematerial removalVSAvoidsample damage and preferential sputtering

Core Design Contradiction:

Loss of substanceVSObject-affected harmful factors

Solution Approach 1:

The patent replaces the mechanical ion beam sputtering process with a laser-based ablation system. The laser beam delivers energy to the sample surface, causing material removal through thermal vaporization and plasma formation rather than mechanical bombardment. This substitution eliminates the preferential sputtering effect that occurs with ion beams while maintaining effective material removal capability for depth profiling.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the fundamental parameter of material removal from mechanical momentum transfer (ion beam) to thermal energy deposition (laser). By controlling laser pulse duration, wavelength, and intensity, the system achieves clean ablation without the preferential sputtering that plagues ion beam methods, particularly for sensitive materials.

Inventive Principle:

Principle #35Parameter changes

2Loss of substance

If conventional ion beam sputtering is used for depth profiling, then material removal is achieved, but the material removal rate is low making depth profiling beyond 5 microns impractical

Engineering Contradiction:

Improvematerial removal rateVSAvoiddepth profiling time

Core Design Contradiction:

Loss of substanceVSLoss of time

Solution Approach 1:

The laser ablation system replaces the slow mechanical sputtering process with a highly efficient thermal vaporization mechanism. The concentrated laser energy rapidly heats and ejects material from the sample surface, achieving material removal rates orders of magnitude higher than ion beam sputtering, thereby enabling practical depth profiling to depths of 200 microns and beyond.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Productivity

If laser pulses are used for material ablation, then material removal rate increases and sample damage is reduced, but new apparatus complexity is introduced

Engineering Contradiction:

Improvematerial removal rateVSAvoidapparatus complexity

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The laser system serves multiple functions: it performs material removal through ablation, provides in-situ cleaning of the sample surface, and can be integrated with the existing electron spectroscopy detection system. This multi-functionality justifies the added complexity by consolidating several operations into a single integrated platform.

Inventive Principle:

Principle #6Universality (Multi-functionality)

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

This approach provides accurate chemical composition and state information with reduced sample damage, enabling deeper depth profiling up to 200 microns, overcoming the limitations of conventional ion beam sputtering.

Implementation Method 1

ablating material from an area on a surface of a sample by irradiating the area with one or more pulses of a laser

Methodology Applied

Scientific EffectLaser ablation: Laser Ablation

Implementation Method 2

irradiating at least part of the area with an excitation beam of electrons or electromagnetic radiation; measuring the intensities and energies of electrons emitted from the at least part of the area of the sample as a result of the excitation beam

Methodology Applied

Scientific EffectPhotoelectric effect: Photoelectric Effect

Data Source

PatentUS20260088243A1Electron spectroscopy apparatus and methods

Publication Date: 2026.03.26 VG SYST LTD

AI summary

There is described a method of determining a chemical composition of a sample using electron spectroscopy, the method comprising: ablating material from an area on a surface of a sample by irradiating the area with one or more pulses of a laser; irradiating at least part of the area with an excitation beam of electrons or electromagnetic radiation; measuring intensities and energies of electrons emitted from the at least part of the area of the sample as a result of the excitation beam; and repeating the steps of: ablating material, irradiating with the excitation beam, and measuring intensities and energies, to determine a quantitative surface depth profile of the chemical composition of at least part of the sample. There is also described an electron spectroscopy apparatus for determining a chemical composition of a sample.