Thin and short cantilevers possess both a low force constant and a high
resonance frequency, thus are highly desirable for atomic force
microscope (AFM) imaging and force measurement. According to some
embodiments, the invention provides small silicon (Si) cantilevers
integrated with a Si tip, for example fabricated from SOI wafers that are
used for reducing the variation of thickness of the cantilevers. In one
example, the fabrication process provided SOI chips containing 40 silicon
cantilevers integrating with an ultra-sharp Si tip. The resolution of
images obtained with these tips was much higher than those obtained with
the commercial tips, while the force constants were much less, that is,
more suitable for imaging soft samples. The availability of such SOI
chips greatly facilitates large scale modification of the surfaces of the
silicon cantilever tips with a monolayer of oligo(ethylene glycol)
derivatives that resist the non-specific interactions with proteins,
rendering them most suitable for imaging and measurement of biological
samples.