(S)TEM ： (Scanning)Transmission Electron Microscopy
Features
TEM is a technique in which a thinned sample is irradiated with a beam of high-energy electrons. The transmitted and scattered electrons are imaged, and the sample structure can thereby be observed at a high magnification.
Advantages
- Sub-nano-meter spatial resolution enables analysis of sample microstructures and lattice defects.
- Evaluation of the crystallinity and identification of the substance.
- Focused ion beam (FIB) preparation enables precise positioning of the region of interest.
- Material composition and chemical state analysis of local areas (by using the attached elemental analyzer together).
Challenges
- Ultra-thin samples necessary. Sufficient thinning might not be possible for some samples.
- Image averaged along the thickness direction (usually about 100 nm); single-atom imaging not possible.
- Sample preparation and observation might alter the sample structure.
Application Examples
- Observation of various shapes and morphologies.
- Evaluation of three-dimensional shapes of ultra-small particles.
- Evaluation of various device dimensions, e.g., film thickness, and field-effect transistor (FET) gate length/width.
- Observation of crystal lattice defects such as dislocations, stacking faults, grain boundaries, and precipitates.
- Crystal lattice evaluation; orientation, crystallinity, grain size.
- Failure cause analysis at a specific location.
- Evaluation of impurities; morphology observation, qualitative analysis by energy-dispersive X-ray (EDX) spectroscopy.
- Evaluation of stress and strain.
Principle of operation
When electrons hit the thin specimen, some travel straight through it, while others are subject to scattering by the atomic lattice. The scattering can broadly be either elastic or inelastic. By selecting the electrons according to their scattering nature, we can gain knowledge of the morphology, crystal structure, composition, and electronic states inside the sample.
Data examples
Data format of deliverables
- High-resolution JPEG files using MST’s download service.
- High-resolution MPT* images.
*MPT is an MST proprietary file format which allows length analysis using MST’s Image Measuring Tool (available upon request).
Specifications
Items for enquiries
Purpose and content of measurement
1. Observation purposes and regions of interest (ROI)
2. Desired magnification and imaging method
Sample information
1. Number of samples, and availability of preliminary samples
2. Sample dimensions and shape
i. Fabricated patterns, if any, and their dimensions
ii. Material/layer structure and film thickness
iii. Evaluation target outline indicated by a diagram
iv. Observation direction (plane/cross-section), cross-sectional direction
3. Handling instructions
i. Susceptibility to cracking
ii. Destructive or non-destructive testing
iii. Required storage environment if different from normal room conditions.
iv. Any other issues
Details on delivery
1. Preferred due date for preliminary analysis report
2. Due date for delivery of final report
Additional requests
1. Possibility of additional observation and analysis
2. Comparison with previously observed samples measured under the same conditions.
［(S)TEM］（走査）透過電子顕微鏡法の分析事例はこちらからご覧ください。