The TGF calibration gratings feature one-dimensional arrays of trapezoidal steps etched into a silicon substrate. The sidewalls of the structures are very smooth and planar surfaces with well-defined orientation formed by the (111) crystallographic planes in monocrystalline silicon. The sidewalls and the horizontal top surfaces form a well defined angle.
TGF11 grating can be used for the assessment of scanner nonlinearity in the vertical direction. Direct calibration of the lateral force can be obtained by analyzing the contact response measured on the flat and sloped facets. This can be done for the calibration of conventional Si probes or cantilevers with an attached colloidal particle with any radius of curvature up to 2μm.