锗衬底上锥形二维亚波长结构的制备

Systematically Investigating Fabrication of Two-Dimensional Conical Sub-Wavelength Structures on Ge Substrate

为了在Ge衬底上制备出锥形二维亚波长结构,文章研究了紫外接触式光刻工艺和反应离子刻蚀工艺对光刻及刻蚀图形的影响。结果发现:由于紫外光的衍射效应,光刻胶图形顶部出现了凹坑,使其有效抗蚀厚度减小,提高光刻胶图形的有效抗蚀厚度,能有效增加最大刻蚀深度;在设计上适当增大掩膜版图形尺寸,即占空比f要略大于理论设定值,可以弥补后续刻蚀过程占空比的缩小;在刻蚀气体SF6中掺入一定量的O2可明显提高Ge的刻蚀深度;降低横向刻蚀速率,从而有利于制备出锥形浮雕结构。

This paper systematically investigates the process of ultraviolet（UV） contact exposure and reactive ion etching.Section 2 of the full paper presents the systematically investigated results,which are given in Figs.1,2 and 3 and Tables 1 and 2,and their analysis.Its core is：（1）there exists a hollow at the top of each relief pattern of the photoresist due to the diffraction of UV light,thus decreasing the effective anti-etching height;（2）raising the effective anti-etching height of the photoresist pattern can effectively increase the maximum etching depth of Ge substrate;（3） when designing the pattern of a mask,enlarging its size can compensate for the reduction of the filling factor of the etched pattern;（4） the etching depth can be greatly increased by introducing O2 into the SF6 etching atmosphere;（5） the conical sub-wavelength structure can be fabricated by adding O2 andby decreasing the speed of lateral etching.