Coplanar Waveguide Sample Carrier for RF In Situ TEM
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Solution Overview
Problem
Conventional in situ transmission electron microscopy (TEM) lacks the capability to adequately investigate electrical stimuli in the radio-frequency (RF) or microwave regime, preventing the microscopic characterization of interactions between RF signals and materials, which is crucial for modern electronic devices.
Innovation Solution
A specimen assembly for in situ TEM that uses a sample carrier with a dielectric substrate and a conductive layer forming coplanar waveguides to transmit broadband alternating electrical signals in the RF or microwave regimes, allowing RF or microwave signals to be applied to a specimen within a vacuum chamber, enabling in situ characterization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If conventional TEM setups are used for signal transmission, then the structure is simple and easy to operate, but signal transmission losses increase significantly at high frequencies
Solution Approach 1:
The patent introduces coplanar waveguides as intermediary transmission structures to bridge the RF source and specimen. These waveguides are specifically designed to minimize signal loss at high frequencies while maintaining compatibility with the TEM vacuum chamber environment, thus resolving the contradiction between transmission efficiency and structural simplicity.
Solution Approach 2:
The patent changes the transmission line parameters by using coplanar waveguide geometry with specific characteristic impedances (50 ohms) and optimized dimensions. This parameter optimization reduces signal attenuation and reflections, thereby minimizing transmission losses without requiring fundamentally new transmission mechanisms.
2Adaptability or versatility
If conventional in situ TEM capabilities are used, then the system is simpler to operate, but the capability to investigate RF or microwave electrical stimuli is insufficient
Solution Approach 1:
The specimen assembly is designed to serve multiple functions: it holds the specimen for TEM imaging, transmits RF/microwave signals to the specimen, and maintains vacuum compatibility. This multi-functionality enables RF regime investigations without requiring separate dedicated equipment, thus improving adaptability while managing complexity.
Solution Approach 2:
The specimen assembly is segmented into distinct functional components: the sample carrier with coplanar waveguides for signal transmission, the specimen mounting area, and the vacuum interface components. This segmentation allows each component to be optimized for its specific function while maintaining overall system compatibility.
3Reliability
If broadband AC electrical signals in RF or microwave regimes are transmitted through conventional cables, then the connection is simple, but transmission losses increase and signal integrity deteriorates
Solution Approach 1:
Coplanar waveguides serve as intermediary transmission structures between the RF cables and the specimen. These waveguides are designed with controlled impedance and optimized geometry to minimize signal reflections and losses, thereby improving transmission reliability while maintaining a relatively simple integrated structure.
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 solution minimizes signal transmission losses and allows for the investigation of RF or microwave interactions with specimens, facilitating the characterization of semiconductor devices and other materials at their operating frequencies, thereby enhancing the capabilities of TEM systems.
Implementation Method 1
a coplanar waveguide can be configured to transmit an electrical signal to a specimen held by the sample carrier. The coplanar waveguide can have a first lead formed by the conductive layer and a pair of second leads formed by the conductive layer
Implementation Method 2
The sample carrier can have a dielectric substrate with a conductive layer that forms a coplanar waveguide
Data Source
AI summary
A sample carrier for in situ transmission electron microscopy (TEM) has a dielectric substrate with a conductive layer that forms a coplanar waveguide. The coplanar waveguide has a first and second leads formed by the conductive layer. The first lead is between an adjacent pair of second leads and is spaced from the second leads by a respective gap. The coplanar waveguide is configured to transmit an electrical signal to a specimen held by the sample carrier, in particular, an electrical signal having a frequency in the radio-frequency (RF) regime (3 kHz-300 GHz), for example, up to 100 GHz. The sample carrier may be mounted to a TEM sample holder, which supports the sample carrier within a vacuum chamber of the microscope and provides electrical connection between the leads of the sample carrier and an RF source external to the vacuum chamber.