絕緣層上覆矽之奈米光柵結構：設計與製作

Abstract

近年來由於網路的普及，應用於光電轉換的元件也因此蓬勃發展。為使光電轉換元件積體化，光波導相關元件於是被廣泛使用。絕緣層上覆矽之中的矽與二氧化矽有很大的折射率差距，且其製程和現有的半導體製程相符，為一合適的光波導材料。而光纖與絕緣層上覆矽為基材之光波導間的尺寸差距使得耦合效率欠佳，故本論文提出一個不需要破壞性測試的垂直式光耦器－光柵耦合器以解決以上問題。

本論文首先就幾項影響因素討論光柵耦合器的設計，設計出操作於Ｃ－波段下的光柵耦合器。藉著模擬軟體FullWAVE，檢視在C－波段之下，由先前分析所設計之光柵耦合器在其擁有製程缺陷以及量測條件誤差下的表現。光柵結構可以在標準的半導體製程下配合電子束微影製作出來。且在電子顯微鏡以及原子力顯微鏡的檢視之下，其實際結構與設計參數相仿，因此驗證可以至出高度周期性結構。本研究展現模擬與製造皆有良好結果，固未來此光柵結構可用於實現緊密之光耦合。

In recent years, the technology of the optoelectronic devices grows as the network is widely spread. The guided-optic device is developed for a compact optoelectronic integrated circuit. The SOI wafer is a promising material for guided optics due to the high refractive index mismatch between Si and SiO2 and the compatibility with CMOS fabrication. The huge mode difference between the fiber and the guided device limits the coupling efficiency, thus the grating coupler that needs no destructive testing is studied in this thesis to solve these problems. The design of the grating coupler is investigated by various factors. The robust finite-difference time-domain (FDTD) software is used to simulate the grating coupler in this thesis. For the targeted C-band applications, the designed grating coupler is examined by the fabrication errors and the coupling errors under the simulations of FullWAVE. The grating structure is made by the standard CMOS fabrication with e-beam lithography, and detailed structure characterizations using SEM and AFM are performed, indicating highly-periodic structures can be fabricated. This study shows promising results in the simulation and fabrication of grating couplers for compact coupling in the future.