Conventional SFM tip deforms surface of polyethylene sample ... while non-contact technique gives sharper image.
A new scanning force microscope technique enables imaging of delicate surfaces without risk of surface damage caused by contact with the tip.
Commercially developed by Park Scientific Instruments, Sunnyvale, CA, the non-contact--or attractive-mode--SFM technique uses the long-range van der Waals forces between the tip and the sample to map the surface's topography. The tip remains 50 A to 100 A from the surface.
The company's Ultralevers silicon cantilevers with integral probe tips used in the attractive-mode technique offer improved image resolution over instruments using low force constant cantilevers and traditional pyramidal tips (left), as shown by the accompanying images of a polyethylene sample.
The new tips (below) are conical in shape with an improved nominal radius of 100 A, compared with conventional pyramidal tips at 400 A.
The higher aspect ratio of the new tips results in truer imaging of steep sidewall and deep trench surface features.
Increased cantilever thickness offers higher force constants, making attractive mode operation possible.
The technique can be used to study surfaces such as soft polymers, biological samples, and organic materials.
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|Title Annotation:||scanning force microscope|
|Publication:||R & D|
|Date:||Apr 1, 1992|
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