用碳氟聚合物作為濕蝕刻阻擋層製作鋸齒狀矽光柵結構與其FTIR與拉曼光譜量測

Abstract

本篇論文針對如何適當使用阻擋層並利用濕蝕刻製程原理來有效製作三角形與鋸齒狀光柵以及矽光柵在紅外光下的異常穿透與拉曼光譜量測來作一系列的探討， 藉由電子束微影技術與非等向性濕蝕刻原理，於矽基板上製作一維的光柵結構，並在掃描式電子顯微鏡下觀察，搭配阻擋層長度與蝕刻時間的變化，我們也成功做出鉅齒狀的光柵結構，實驗的過程中也讓我們發現RIE完所殘留的碳氟聚合物能直接拿來做為阻擋層，並由XPS來分析其元素組成。 接著將所製作出的樣品並進行FTIR的紅外線量測與拉曼光譜量測，比較不同深度與形狀的矽光柵，其紅外光穿透行為的變化。我們利用光動量守恆和色射關係式，即推出某些異常穿透現象發生的波長位置，然而還有部分異常穿透波長位置，無法用上述理論來解釋。拉曼光譜的量測則發現角度越尖的光柵結構，其尖角處訊號強度會越強。

In this work, we fabricate Si sawtooth and triangle grating by wet etching .Then study the transmittance of infrared light and the intensity of Raman spectrum. By electron beam lithography and anisotropic wet etching principle, we fabricate one-dimensional grating structure on the Si substrate, then observed by SEM. By Changing length of mask and etching time, we successfully fabricate sawtooth grating. During the experiment we also found that the residue after RIE process can be used as wet etching mask which was a kind of Carbon-Fluorine polymer, and then analyze it by XPS . Then measuring the samples by FTIR and Raman spectrum. Comparing the infrared transmittances with different depths and angles of silicon grating.. We use light momentum conservation and dispersion relation to find out some wavelength position of extraordinary transmission phenomenon. there are some extraordinary transmission wavelength which can’t be explained by the theory. By Raman spectrum, we found that the sharp grating has stronger signal of Raman spectrum.