The Dimension 3000 is a scanned tip SPM which allows for great flexibility: imaging in liquids as well as imaging with magnetic and non-ambient temperature stages. What is lost is lateral stability of the scanner due to the large lateral scan range of 100 μm. The vertical noise floor is still quite good at ~ 0.75 Å.To test the noise floor one images freshly cleaved mica. The image is a 25 nm scan of V4 mica in contact mode with nearly zero normal force-- i.e. no deflection. Image drift has been minimized by scanning for an extended period to eliminate any piezo hysteresis and to allow the sample mounting to fully relax. The Z-limit has been set to its minimum value for maximum Z-piezo digital resolution. A sharpened Veeco SiN DNP-S probe with 0.12 N/m spring constant was used.
Note that some period structure is visible through the noise. 2D Fourier transform of the image shows significant noise bands in the vertical direction-- i.e. the slow scan direction-- which prevents spectral filtering and recovering of a high resolution atomic level image. The roughness, Ra, is 0.95 Å which is a bit above the spec'd noise floor of 0.75 Å.
This image is a 500 nm AFM image taken with an Veeco OTESP Si tapping tip. Again the X-Y hysteresis and sample drift were minimized by scanning for some time. The Z-limit was minimized for maximum Z-piezo digital resolution. Note the Ra of 0.45 Å which is a typical noise floor measurement for this system.
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