X-ray imaging techniques based on grating interferometers rely on transmission gratings to detect x-ray refraction and
scattering in a sample. Gratings periods below 2 microns are challenging to realize due to the high aspect ratio of the
structures. We propose a method to fabricate transmission gratings with sub-micron periods over centimeter areas by
multilayer coating of a staircase (echelle) substrate. The advantage of this approach is the high aspect ratio of multilayer
coating and the large area of the echelle substrate. The staircase pattern is etched on the surface of a silicon wafer
through anisotropic etching. Multiple layers are deposited on the horizontal surfaces of the stairs by magnetron
sputtering in a single run. The layers alternate between two materials of different absorption coefficients or refractive
indices. The layer thickness d is designed to be (stair height)/2N, where 2N is the total number of layers. The incident xray
beam is parallel to the layers and oblique to the wafer surface. Each stair of the echelle substrate forms a micro
grating of period 2d, and the array of micro gratings together act as a single grating over a large area given the right
continuity conditions. The grating period potentially can be below 100 nm. We present theoretical description of wave
diffraction by the grating array, and results of the first fabrication test with magnetron sputtering deposition.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.