透射电子显微镜

Transmission Electron Microscopy (TEM) and Scanning Transmission Electron Microscopy (STEM) Analysis

Technical Principle
TEM and STEM are analogous techniques that utilize electron beams for sample imaging, achieving remarkable resolutions of 1-2Å. These methods employ high-energy electrons (80keV-200keV) to penetrate electron-transparent samples (typically ~100nm thick). While offering superior spatial resolution compared to SEM, TEM/STEM requires more sophisticated sample preparation protocols.

Key Applications
• Metrology with 1nm resolution capability
• Identification of nanoscale defects in ICs (embedded particles, via residues)
• Nanocrystalline phase determination
• Nanoparticle characterization (size, core/shell studies, agglomeration, annealing effects)
• Catalyst research
• Nanoscale elemental mapping
• III-V superlattice characterization
• Crystal defect analysis (dislocations, grain boundaries, voids, stacking faults)

Advantages of TEM/STEM
• Unparalleled spatial resolution for elemental mapping among analytical techniques
• Sub-nanometer (<1Å) imaging resolution
• Capability for nanoscale crystallographic analysis
• Strong contrast differentiation between crystalline/amorphous materials without chemical staining

Technical Limitations
• Extended sample preparation time (1-4 hours)
• Limited sampling volume (typical specimen dimensions: 100nm thickness × 5μm×5μm area)
• Potential beam sensitivity for certain materials under high-energy electron irradiation

Performance Specifications

• Resolution: 1-2Å (image), <1nm (elemental mapping)

• Accelerating Voltage: 80-200kV

• Typical Sample Thickness: ≤100nm

• Analytical Capabilities:

  • Crystallographic structure determination

  • Compositional mapping (EDS/EELS)

  • Defect characterization at atomic scale