Browse Prior Art Database

Force Sensor with Simultaneous Detection of Vertical and Lateral Movements

IP.com Disclosure Number: IPCOM000121684D
Original Publication Date: 1991-Sep-01
Included in the Prior Art Database: 2005-Apr-03
Document File: 3 page(s) / 64K

Publishing Venue

IBM

Related People

Bayer, T: AUTHOR [+4]

Abstract

A raster force microscopy sensor normally consists of a cantilever, the front end of which is provided with a tip and the rear end of which is fixed to a macroscopic holding element.

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This is the abbreviated version, containing approximately 75% of the total text.

Force Sensor with Simultaneous Detection of Vertical and Lateral
Movements

      A raster force microscopy sensor normally consists of a
cantilever, the front end of which is provided with a tip and the
rear end of which is fixed to a macroscopic holding element.

      Fig. 1 shows how vertical movements of the cantilever are
optically detected at the back of the cantilever.

      Figs. 2A and 2B are cross-sectional views of a new type of
cantilever proposed in this article.  The cantilever preferably
consists of monocrystalline silicon which permits the desired mirror
surfaces to be anisotropically etched. For this purpose, the back of
the cantilever is designed as a V-shaped groove (111-crystal planes).
Fig. 2A shows the etch process which is carried out until the two
111-planes are touched.  This etch process leads to a highly
effective etch stop, as the 111-plane etches 300 times more slowly
than the 100-plane.  In Fig. 2B, the etch process is interrupted at
an earlier time, retaining a horizontal 100-plane as a groove base.
The latter etch process, similar to state-of-the-art cantilevers,
allows the laser beam to be reflected back onto itself.

      Figs. 3A and 3B show details of the production process of this
new cantilever.  After the tip has been formed on the front side of
the cantilever, the front side is coated with an Si3N4 protection
layer.  Then, silicon is KOH-etched from the back, when the
111-planes start to form (Fig. 3B). The etch...