真空紫外闪耀硅光栅的制作

摘 要：本文基于单晶硅在KOH溶液中的各向异性刻蚀的特性，在相对于Si（111）面偏向切割5度的单晶片上制作1200线/毫米的闪耀光栅。工艺上结合全息干涉以及光刻胶灰化技术，得到小占宽比、平滑且干净的光刻胶掩模，用湿法刻蚀将光栅图形转移到硅单晶表面的天然氧化层上，并将其作为硅各向异性刻蚀的掩模，成功获得接近于理想槽形的锯齿形闪耀光栅。经过原子力显微镜对闪耀面进行分析，表面均方根粗糙度约为0.2nm，这对光栅在短波光学上的应用显得尤为重要。经过真空紫外波段的效率测量，发现光栅在135nm波长处显示出良好的闪耀特性。此方法可以应用于极紫外和软X射线波段的光栅制作上，在获得较高的槽形效率的同时，可以大大减少其制作难度及成本。

Vacuum-ultraviolet Blazed Silicon Grating Anisotropically Etched in KOH Solution

Abstract: Combined with the technigue of holographic interference and the ashing of photoresist, a straight and clean mask of phtoresist with small line-to-period can be fabricated on off-cut silicon (111) wafers. We present a simple and convenient method of controlling the profile of a blazed grating that consists of using patterned native oxide layer as the mask of anisotropic etching to obtain near-ideal grooves of sawtooth. With the blazed grating profile well controlled by this technique, a 1200 g/mm blazed grating was fabricated, which had a blaze angle of 5.0° and smooth blaze facets of about 0.2 nm rms. The grating was measured to blaze at the wavelength of 135 nm. It is believed that high-groove-efficiency blazed gratings used in the wavelengths of extreme ultraviolet and soft x-ray can be easily fabricated by this method at normal or near normal incidence.