Semiconductor Sample Support for Electron Microscopy
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Solution Overview
Problem
Existing sample support structures for electron microscopy suffer from thermal and mechanical instability, leading to sample drift and electron charging issues, particularly at low temperatures, due to the mismatch in thermal expansion coefficients between metal grids and carbon films, which limits high-resolution imaging and tomographic analysis.
Innovation Solution
A sample support structure made from semiconductor materials with integrated holes, featuring a base and a sample support layer with enhanced rigidity and conductivity, manufactured using a multi-layer etching process to achieve specific dimensions and properties, such as a Young's modulus greater than 300 GPa and resistivity less than 10 ohm-cm, minimizing drift and electron charging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a thin carbon film is placed on a metal grid for sample support, then the sample support allows electron microscopy analysis, but the carbon film drifts due to thermal and mechanical instability degrading image resolution
Solution Approach 1:
The patent changes the material parameters of the sample support by using semiconductor materials (silicon, silicon nitride, silicon carbide) instead of traditional metal grids. These materials have matched thermal expansion coefficients with carbon films, eliminating the drift problem while maintaining mechanical stability for high-resolution imaging
Solution Approach 2:
The patent employs composite material structures where semiconductor materials are combined with carbon films in a compatible configuration. The semiconductor substrate provides mechanical stability and thermal compatibility, while the carbon film maintains its function as a stable support for biological specimens during electron microscopy analysis
2Area of stationary object
If a metal grid is used to support the carbon film, then the sample support structure is mechanically stable, but the grid bars block imaging area and limit tomographic analysis
Solution Approach 1:
The patent extracts and removes the problematic grid bars from the sample support structure. By using a continuous semiconductor substrate instead of a grid, the blocking bars are completely eliminated, maximizing the imaging area while the semiconductor material itself provides the necessary mechanical stability through its inherent strength and matched thermal properties
3Reliability
If traditional carbon film on metal grid is used, then the sample support is conductive at room temperature, but conductivity degrades at very low temperatures causing electron charging
Solution Approach 1:
The patent changes the material composition from carbon-based to semiconductor-based materials. Semiconductor materials like silicon and silicon carbide maintain their electrical conductivity properties across a wide temperature range including cryogenic conditions, preventing electron charging while the carbon film layer preserves its biocompatibility and structural function
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
The semiconductor-based sample support structure provides minimal drift, increased rigidity, improved conductivity at low temperatures, and reduced electron charging, enabling high-resolution imaging and tomographic analysis without the limitations of traditional carbon films on metal grids.
Implementation Method 1
The sample support may include monocrystalline silicon, polycrystalline silicon, amorphous silicon, silicon nitride, silicon carbide, boron nitride, aluminum nitride, graphite, graphene, other semiconductor materials or ceramics
Implementation Method 2
The sample support structure contains a sample support manufactured from a semiconductor material... improved conductivity at low temperatures... decreased electron charging
Implementation Method 3
A method of making a sample support structure is provided. The method may include etching a sample support layer to a first thickness... etching a base layer to a second thickness
Data Source
AI summary
A sample support structure comprising a sample support manufactured from a semiconductor material and having one or more openings therein. Methods of making and using the sample support structure.