AFM

Atomic Force Microscopy (AFM)

Also known as Scanning Probe Microscopy (SPM), Scanning Force Microscopy (SFM)

Atomic-force microscopy (AFM) or scanning-force microscopy (SFM) is a type of scanning probe microscopy (SPM), with demonstrated resolution on the order of fractions of a nanometer, more than 1000 times better than the optical diffraction limit. The information is gathered by “feeling” or “touching” the surface with a nano-engineered probe. Piezoelectric elements that facilitate tiny but accurate and precise movements on (electronic) command enable very precise scanning.

Industries:

Thin films development, semiconductors, MEMS, optical components, coatings, piezoelectric materials, magnetic materials.

Atomic Force Microscopy for Advanced Optical Components:

Read White Paper

Covalent has the following capabilities:

AFM Modes Sample Typical data Typical Turnaround Time
Contact AFM All types Surface topography, 3D mapping, Ra, Rq < 48h
Tapping Mode AFM All types Surface topography, 3D mapping, Ra, Rq, phase imaging < 48h
Electrostatic (EFM) Composite Metal, Semiconductor films Local charge distribution < 48h
Magnetic (MFM) Magnetic films Magnetic domain structure, magnetization hysteresis, magnetic coercive field < 48h
Piezo response (PFM) Piezo materials, MEMS Piezo domain structure, polarization vector and switching, ferroelectric coercive field < 48h
Peak Force AFM Thin film Roughness, Surface topography < 48h
Peak Force Quantitative Nanomecanical (QNM) Polymer Coating Mechanical properties (adhesion, modulus and dissipation), Phase imaging, Polymer domains < 48h
Kelvin Probe (AM-KPFM) Thin films, Semiconductors Surface potential, work function < 48h
Scanning Capacitance (SCM) Semiconductor films films Dopant profile, relative capacitance < 48h

Measurements:

  • Topography and surface quality: complete 3D model of sample’s surface with a sub-nanometer lateral resolution and sub-Å vertical resolution.​
    • full 3D/2D topography
    • roughness (Ra, Rq)
    • step height
    • cross sections
    • particle counts
    • defect analysis
  • Mechanical characterization and phase mapping: adhesion, modulus and dissipation
  • Magnetic domains, magnetization hysteresis, magnetic coercive field.
  • Surface potential and work function.
  • Piezoelectric domains, polarization vector and switching, ferroelectric coercive field.
  • Electrostatic gradients, capacitance variations.

Uses & Limitations:

  • What it is great for:
    • Quantified topography/ roughness of very smooth samples
    • Best z resolution
    • Surface imaging of insulating samples with no extra sample prep
    • High definition functional properties mapping (mechanical, electric, magnetic, piezo)
    • Imaging topography of samples in liquid
    • defect analysis
  • Limitations:
    • Requires expertise for reliable results, even on seemingly easy samples
    • No compositional mapping available

Example Outputs

Optical Flat Surface (AFM height sensor – 3D render): AFM reveals very fine scratches on this highly polished surface.

Height Sensor

Freshly cleaved graphite (AFM height sensor – 2D render, 3D render below): atomic steps are visible on this scan.

INSTRUMENTS

Bruker Nano Dimension (Icon and FastScan heads)

AFM in Cleanroom