Interferometric Sample Measurement Using Electric Field Amplitudes
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Solution Overview
Problem
Conventional contact-type measurement methods for determining the physical properties of samples, such as impurity concentration in semiconductors, risk damaging the sample due to improper probe placement.
Innovation Solution
An interferometric measurement method using an interferometric measurement apparatus that splits measurement light into two paths, one with and one without a sample, and measures interference light intensity to determine electric field amplitudes, allowing non-contact evaluation of physical properties like carrier density in semiconductors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a contact-type measurement method using a probe is used to measure the physical property of a sample, then measurement can be performed, but the sample may be damaged due to improper probe placement
Solution Approach 1:
The patent replaces the mechanical contact measurement system with an optical measurement system. Instead of using a physical probe that contacts the sample, the invention uses light (electromagnetic radiation) to interact with the sample and measure its physical properties through optical absorption characteristics, thereby eliminating mechanical damage while maintaining measurement capability
Solution Approach 2:
The patent introduces light as an intermediary between the measurement device and the sample. The light serves as a mediator that carries measurement information without physically contacting the sample, allowing the extraction of physical property data (such as carrier concentration) through optical absorption measurements while avoiding direct mechanical interaction that could cause damage
2Object-affected harmful factors
If a non-contact measurement method is used to avoid sample damage, then sample integrity is maintained, but measurement precision may be reduced
Solution Approach 1:
The patent utilizes changes in optical absorption parameters at different frequencies to extract physical property information. By measuring absorption characteristics across a frequency spectrum and analyzing the plasma frequency and absorption coefficient, the system achieves precise determination of carrier concentration and other physical properties without contact, maintaining both non-destructiveness and measurement accuracy
Solution Approach 2:
The patent replaces mechanical contact measurement with optical field interaction, using electromagnetic radiation to probe the sample's physical properties. This substitution enables non-contact measurement while achieving high precision through the analysis of light-matter interaction parameters such as absorption coefficient and plasma frequency
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 accurate, non-destructive measurement of semiconductor properties by converting interference light intensity into electric field amplitudes, facilitating high S/N ratio measurements and avoiding sample damage.
Implementation Method 1
an interferometric optical system that includes: a beam splitter that splits the measurement light into a first split light and a second split light
Implementation Method 2
a photomultiplier tube that outputs an electrical signal value corresponding to an incident light intensity of interference light
Data Source
AI summary
An interferometric measurement method using an interferometric measurement apparatus includes a first step of acquiring a first interference waveform in a first state by changing an optical path length difference between a first optical path and a second optical path in the first state in which a sample is not disposed in the second optical path, a second step of converting the first interference waveform into a first electric field amplitude waveform, a third step of acquiring a second interference waveform in a second state by changing the optical path length difference in the second state in which the sample is disposed in the second optical path, a fourth step of converting the second interference waveform into a second electric field amplitude waveform, and a fifth step of acquiring a physical property of the sample based on the peak amplitudes of the first and second electric field amplitude waveforms.