底切蝕刻鈮酸鋰元件結構之製作

Fabrication of Under-Cutting Structures on Lithium Niobate

張文哲(Wen-Che Chang)

指導教授 ： 王子建

國立臺北科技大學/電資學院/光電工程系研究所/碩士(2010年)

摘要

本論文在鈮酸鋰晶體上製作出具有底切脊形結構之光波導元件，藉由其橫向與縱向之高折射率對比，能夠有效的侷限光場，以降低光波導於小環形半徑光波導傳播時所造成的損失。底切蝕刻結構的製作是使用離子佈植與濕式蝕刻的技術來達成，製程上首先製作特定圖樣的鉻膜與光阻作為濕式蝕刻遮罩與離子佈植遮罩，然後佈植氦離子在鈮酸鋰晶體上，於特定深度產生晶格破壞，經由濕式蝕刻鈮酸鋰，可將脊形下方的晶格破壞區移除，即可產生底切脊形結構。利用此製程步驟，實驗上製作出具有底切脊形結構的直波導、微碟形、環形濾波器等光波導元件，論文中並討論實驗參數對於底切脊形結構的影響。所研製具有底切脊形結構之積體光學環形濾波器，當環形半徑為100μm、耦合區長度為120μm時，所量測得到的FSR接近其理論值。

關鍵字

光波導 ； 環形濾波器 ； 鈮酸鋰,離子佈植 ； 濕式蝕刻

並列摘要

Waveguide devices with under-cutting structure on lithium niobate are produced in this thesis. By means of high index contrast of the under-cutting structure in the lateral and vertical directions, the propagating optical field can be effectively confined and the propagation loss of the curve waveguide with small radius is reduced. Under-cutting structure is formed by using ion-implantation and wet-etching techniques. In the experiments, chromium and photoresist are used as wet-etching mask and ion-implantation mask, respectively. He+ ion implantation is utilized to produce the lattice-damage region at the specified depth in lithium niobate. By the wet-etching technique, the lattice-damage region beneath the ridge structure is removed to form under-cutting structure. By using the proposed method, various waveguide devices with under-cutting structure, including straight waveguide, microring resonator, microdisk resonator, are fabricated. The effects of the fabrication parameters on the under-cutting structure are also discussed. For the fabricated microring resonators with under-cutting structure, the measured FSR is close to the theoretical one.

並列關鍵字

optical waveguide ； microring resonator ； lithium niobate ； ion implantation ； wet etching

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