Optimization of structural parameters and fabrication of monocrystalline silicon gratings with small blazed angle

In order to meet the requirements of the national synchrotron radiation source, the anisotropic wet-etching technology of monocrystalline silicon grating with small blazed angle is studied, and the blazed grating suitable for the medium wave soft X-ray band is prepared. Based on the rigorously coupled wave theory, the structural parameters and process tolerance of the small blazed angle grating are designed. In the crystal alignment process, the crystal orientation of the silicon wafer is determined by ring-preetching, and then the grating mask is aligned with the crystal direction of monocrystalline silicon <111> based on the frequency doubling adjustment method. At the same time, the effect of the photoresist ashing technique and the active agent on the groove quality of the grating is investigated, and the scintillating gratings close to the ideal sawtooth groove shape are successfully prepared by the monocrystalline silicon anisotropic wet etching process. The experimental results show that the blazed angle of the prepared grating is 1°, the linear density is 1200 gr/mm, and the root mean square roughness of the blazed surface is less than 0.5 nm. This method can be applied to the fabrication of the medium wave soft X-ray blazed grating, which can greatly reduce the difficulty and cost of fabrication while achieving high diffraction efficiency.