In Situ Fluid Freezing Chip for High-Resolution TEM Imaging
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Solution Overview
Problem
Current in situ transmission electron microscopes struggle to capture high-resolution, instantaneous information during dynamic processes due to high-speed molecular movement, such as changes in element valence state and molecular structure, which is crucial for understanding chemical reactions at molecular and atomic scales.
Innovation Solution
A transmission electron microscope high-resolution in situ fluid freezing chip is designed with a silicon substrate, metal bonding layer, and semiconductor films to enable micro-area rapid freezing and low sample drift, allowing precise temperature control and high imaging resolution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If in situ transmission electron microscopy is used to provide a full dynamic gas-fluid environment, then more dynamic structural change information can be captured, but high-resolution instantaneous information cannot be captured due to high-speed molecular movement
Solution Approach 1:
The system performs preliminary rapid freezing of the sample before observation. The freezing layer with Peltier elements and liquid nitrogen channels pre-cools and rapidly freezes the sample to preserve instantaneous high-resolution structures before molecular movement blurs the details, enabling subsequent high-resolution imaging of captured states
Solution Approach 2:
The system utilizes phase transition of liquid nitrogen to achieve rapid cooling. Liquid nitrogen flows through channels in the freezing layer, transitioning from liquid to gas phase, absorbing heat and rapidly freezing the sample to preserve instantaneous molecular and atomic structures for high-resolution observation
2Measurement precision
If micro-area rapid freezing is performed during in situ testing, then high-resolution instantaneous information can be captured, but sample drift may occur during freezing and imaging
Solution Approach 1:
The system divides the sample chamber into an observation chamber and a freezing layer with separate temperature control zones. The upper chip maintains observation temperature while the lower chip's freezing layer performs rapid freezing, allowing localized temperature control that minimizes thermal stress and drift during freezing while maintaining stability in the observation region
Solution Approach 2:
The chip structure uses asymmetric design with the upper chip having a slightly smaller area than the lower chip, with center windows aligned for electron transmission. This asymmetric configuration optimizes heat flow paths and structural stability, reducing sample drift during the freezing process while maintaining imaging quality
3Ease of manufacture
If a conventional chip structure is used, then manufacturing is simpler, but micro-area rapid freezing with precise temperature control cannot be achieved
Solution Approach 1:
The system changes temperature parameters dynamically using Peltier elements that can rapidly switch between heating and cooling modes. The freezing layer temperature is controlled independently from the observation chamber, enabling precise micro-area rapid freezing (achieving -196°C rapidly) while maintaining simpler overall chip manufacturing through standard semiconductor fabrication processes
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 chip achieves rapid freezing and high-resolution imaging with minimal sample drift, capturing critical instantaneous information during chemical reactions, enhancing the understanding of molecular and atomic processes.
Implementation Method 1
the lower chip is provided with a Peltier element, a freezing layer, an insulating layer, an opening, and a second center window; the freezing layer is provided with three contact electrodes, six pairs of semiconductor films, and a conductive metal film
Implementation Method 2
In order to obtain these information, technicians need to perform micro-area rapid freezing during in situ testing in combination with high-resolution STEM/EDS/EELES characterization
Implementation Method 3
an upper chip and a lower chip combined via a metal bonding layer, the upper chip and the lower chip each include a front side and a back side, the front side of the upper chip is directly bonded to the front side of the lower chip via the metal bonding layer
Implementation Method 4
the upper chip and the lower chip are each made of a silicon substrate with silicon nitride or silicon oxide on two sides
Implementation Method 5
the freezing layer is provided with three contact electrodes, six pairs of semiconductor films, and a conductive metal film; one ends of the six pairs of semiconductor films are lapped on the conductive metal film, and the other ends of the six pairs of semiconductor films are lapped on the electrodes
Data Source
AI summary
A transmission electron microscope high-resolution in situ fluid freezing chip includes a lower chip and an upper chip. The lower chip is provided with a support layer, a freezing layer, an insulating layer, an opening, and a center window. The freezing layer is provided with contact electrodes, semiconductor films, and a conductive metal film. The center window is surrounded by the conductive metal film; the contact electrodes are disposed at an edge of the chip. One ends of the semiconductor films are lapped on the conductive metal film, and the other ends are lapped on the electrodes. In the outer edge of the conductive metal film, silicon is etched to form the opening. The support layer covers the opening. The conductive metal film is disposed on the support layer. A plurality of holes are provided in the center window.