A linear-field scanning-force microscope: Application to x-ray gabor holography

Abstract

We have built a linear field Scanning Force Microscope to readout x-ray Gabor holograms recorded in photoresist. A field linearity yielding one half or less pixel registration error (for 10-50nm pixel sizes) across the scanned hologram is needed so that the resulting reconstruction is not significantly degraded. The desire for a large (75μm)2 and linear scanning field necessitated designing our own stage since these conditions could not be met commercially.Gabor holography is well positioned to exploit flash x-ray sources, such as x-ray lasers and free electron lasers, as well as ultra-bright third generation synchrotron sources as a sub-50nm resolution imaging technique for biological samples. Gabor holography requires no optics (except for a monochromator with λ/Δλ ∽ 500) and no sample prefocusing since the image is focused in the reconstruction process. Furthermore, sample alignment is eased since the area of illumination can be quite large. In fact, Gabor holography can be used to image large fields with multimode sources with the resulting numerical aperture, and hence resolution, being limited by the size of a single mode.