Scanning Probe Microscopy/Atomic Force Microscopy (SPM/AFM)

Scanning Probe Microscopy (SPM), more commonly known as Atomic Force Microscopy (AFM), provides atomic or near-atomic-resolution surface topography, which is ideal for determining angstrom-scale surface roughness on a sample. In addition to presenting a surface image, AFM can also provide quantitative measurements of feature sizes, such as step height, and other sample characteristics, such as capacitance measurements for identifying carrier and dopant distributions

Evans Analytical Group® (EAG) uses this technique in a variety of applications to help customers across a range of industries. Examples include:

• Assessing wafers (SiO₂, GaAs, SiGe, etc.) before and after processing
• Determining processing effects (e.g. plasma treatment) on contact lenses, catheters, coated stents, and other biomedical surfaces
• Examining the impact of surface roughness on adhesion and other process challenges
• Assessing trench shape/cleanliness on patterned wafers
• Determining whether morphology is the source of surface hazes

When performing an SPM or AFM analysis, the experience of the analyst is invaluable, and our scientists have seen a wide variety of samples and are attuned to the idiosyncrasies of the technique. This allows us to account for potential artifacts (e.g. tip convolution) that may occur during the analysis. When necessary, we acquire multiple images using multiple tips to ensure an accurate representation of the sample morphology.

Scanning Capacitance Microscopy (SCM)

We can acquire SCM and AFM images simultaneously, allowing you to view two-dimensional carrier distributions, which is particularly important to the semiconductor industry. Unlike Secondary Ion Mass Spectrometry (SIMS), which only shows the vertical distribution of doping elements, SCM can show the lateral distribution of active dopants. This enables semiconductor companies to study the affect of lateral dopants on device performance much more accurately.

View Application Notes

Ideal Uses for SPM & AFM Analysis		Relevant Industries for SPM & AFM Analysis
Three-dimensional surface topographic imaging, including surface roughness, grain size, step height, and pitch Imaging of other sample characteristics, including magnetic field, capacitance, friction, and phase		Aerospace Automotive Biomedical/biotechnology Compound Semiconductor Data Storage Defense Displays Electronics Industrial Products Lighting Pharmaceutical Photonics Polymer Semiconductor Solar Photovoltaics Telecommunications
Strengths of SPM & AFM Analysis		Limitations of SPM & AFM Analysis
Quantifying surface roughness Whole wafer analysis (150, 200, 300 mm) High spatial resolution Imaging of conducting and insulating samples		Scan range limits: 100 microns laterally and 5 microns in z direction Potential problems with samples that are too rough and oddly shaped Tip-induced errors possible

Application Notes