摘要

本論文為利用垂直鏡面反射器的應用來設計製成ㄧ半導體光濾波器。藉由垂直蝕刻鏡面的反射，入射至多模干涉耦合器(Multi-Mode interference ，MMI)的光模，來完成的光波導鏡面反射器。採用垂直鏡面的設計，使一入射至多模干涉耦合器的光模轉彎，並且適當的改變多模干涉耦合器的長度，達到所需要的分光比及最高輸出功率。在此論文中為了讓光模在垂直反射的鏡面產生全反射，所以我們利用乾式蝕刻ICP-RIE來製作較溼式蝕刻更為垂直且平滑的反射鏡面。
在設計半導體光濾波器中，用ㄧ個2×2的多模干涉耦合器製作出轉彎90°的垂直鏡面反射器及腔體長度的設計，可以達到特定比例分光的效果。若利用兩個垂直鏡面反射器及彎曲波導，所形成的環型共振腔，便可取代傳統形式的劈裂面費比-普洛共振腔，同時也為ㄧ具有波長選擇特性的光濾波器。
在元件製程技術中，此論文皆以乾式蝕刻(ICP-RIE)高密度的電漿系統作為主要蝕刻結構的技術。先將磊晶片表面利用黃光微影製程定義出元件圖案，以ICP-RIE蝕刻出脊狀波導，再對彎曲波導及反射器外圍作深蝕刻，以減少曲率所造成的損耗。而在反射鏡面的位置也再次利用ICP-RIE蝕刻更為平滑的垂直面。接下來以高分子材料進行平坦化製程，最後鍍上金屬訊號電極。
最後，在量測元件特性時，可以在直線的部分由明顯的費比-普洛共振計算其直線損耗為35.68dB、分光器的部分量測得知其具有85:15的分光效果，而在濾波器則可以得到FSR=81GHz的光譜傳輸圖。

Abstract

The purpose of this thesis is to design and fabricate optical waveguide reflectors by using vertical mirror reflector. In order to reflect the incident optical mode of multi-mode interference coupler, we fabricate the etched vertical reflective mirror surface with dry etch processes. We used the design of etched vertical mirror surfaces to bend the incident optical mode, and changed the length of multi-mode interference coupler for the power splitting ratio and high power output. In order to make total internal reflection in vertical reflective mirror, we used ICP-RIE dry etching process to fabricate vertical and smooth mirror.
In this part of design the semiconductor optical filter, we design the 90o vertical mirror reflector and the length of MMI by using a 2×2 multi-mode interference coupler to get the power splitter with coupling coefficient. We comprise the ring resonator by two vertical mirror reflector and bended waveguide to displace the cleaved of Fabry-Perot resonator in tradition.
In fabrication process, we using dry etching (ICP-RIE) process that is the plasma system high density in all part of this paper. first, we defined the device pattern by using photo-lithography technique in our sample . Second, we etched ridge waveguide by using dry etching ICP-RIE method. In order to decrease the scattering loss, we deep etched bended waveguide and the reflector. Then, we etched the reflector mirror by ICP-RIE dry etching process to get smoother surface. Finally, we used polyimide to flatten the sides of the ridge waveguide and evaporated metal electrode.
In the device characteristic, we get the waveguide loss in 35.68dB by Fabry-Perot resonator and a power splitter with 85 percent and 15 percent output. Finally, we could get a transmission frequency about 81GHz from optical transmission spectrum in the filter device.

目錄

第一章 簡介.........................................................................................1
1-1前言.........................................................................................1
1-2論文架構...............................................................................3
第二章 多模干涉耦合器....................................................................4
2-1多模干涉耦合器之原理....................................................5
2-1-1 傳播常數.....................................................................5
2-1-2 自我成像原理.............................................................7
2-2多模干涉耦合器之模擬..................................................11
第三章 元件設計................................................................................12
3-1 脊狀波導............................................................................12
3-2 彎曲波導............................................................................13
3-3 垂直鏡面反射器..............................................................15
3-3-1 2x2(K=0.85)之MMI模擬...........................................16
3-3-2 2x2(K=0.85)之交錯型MMI模擬...............................17
3-3-3 2X2 (K=0.15) MMI反射鏡面器................................18
3-3-4 反射鏡面分光器之模擬結果...................................19
3-4 環形共振腔.......................................................................21
3-4-1 鏡面環形共振腔分析方法.......................................25
3-4-2 垂直蝕刻鏡面光波導反射器模擬結果...................27

第四章 元件製程與量測.................................................................29
4-1 磊晶片資料.......................................................................29
4-2 蝕刻技術............................................................................31
4-2-1 濕式蝕刻(Wet Etching) ............................................31
4-2-2 乾式蝕刻(Dry Etching) ............................................33
4-3 製成流程圖.......................................................................35
4-4 製程示意圖.......................................................................36
4-5 製程步驟............................................................................40
4-6 元件量測............................................................................56
4-6-1 I-V量測...................................................................56
4-6-2 被動元件量測結果.................................................57
第五章 結論.........................................................................................60
參考文獻................................................................................................62









圖目錄

圖2-1 10μm MMI內部模態..................................................................4
圖2-2 2X2多模干涉耦合器..................................................................5
圖2-3 二維的多模階級引數波導..........................................................5
圖2-4 MMI形成的多個模態數............................................................7
圖2-5 MMI入射一光場的 成像位置.........................................8
圖2-6 K=0.15MMI示意圖..................................................................10
圖2-7 利用Fimmwave模擬有效寬度10μm 的MMI前兩個模態.11
圖3-1 脊狀波導之示意圖...................................................................12
圖 3-2 (a)圓柱座標下的彎曲波導幾何形狀.....................................13
(b)等效為直角座標系統折射率分佈....................................13
圖3-3 折射率的變化與模態場型分佈..............................................14
圖3-4 1×1垂直鏡面反射器示意圖..................................................15
圖3-5 (a) K=0.85的2x2MMI................................................................16
(b) BPM模擬傳輸圖.................................................................16
圖3-6 (a) K=0.85的2x2交錯型MMI....................................................17
(b) BPM模擬傳輸圖.................................................................17
圖3-7 2×2 90度轉彎反射器示意圖...................................................18
圖3-8 (a) 2x2(K=0.15) MMI反射鏡面器..........................................19
(b) FDTD模擬傳輸圖..............................................................19

圖3-9 2×2(K=0.15)反射鏡面分光器.................................................19
圖3-10 反射鏡面分光器模擬結果......................................................20
圖3-11 環形共振腔示意圖..................................................................22
圖3-12 FSR示意圖...............................................................................22
圖3-13 (a)直線MMI搭配彎曲波導之環形共振腔示意圖................24
(b) 90度轉彎反射器搭配彎曲波導之環形共振腔示意圖....24
圖3-14 鏡面環形共振腔繞行示意圖..................................................25
圖3-15 垂直鏡面反射器之濾波器元件圖形......................................27
圖3-16 垂直鏡面反射器之濾波器模擬結果......................................28
圖4-1 MBE_1.41μm 磊晶片之PL光譜圖......................................30
圖4-2 MBE_1.41μm 磊晶片之EL光譜圖......................................30
圖4-3 多步驟蝕刻技術流程圖..........................................................32
圖4-4 乾蝕刻技術製作脊狀波導流程圖..........................................34
圖4-5 第一道光罩Alightment key....................................................41
圖4-6 光阻曝光時間比較(a) 8s (b) 7s (c) 6s....................................42
圖4-7 金屬掀離後之OM圖.............................................................43
圖4-8 波導SEM圖...........................................................................44
圖4-9 ICP-RIE乾蝕刻後的脊狀波導SEM圖................................45
圖4-10 彎曲波導及MMI漸變深蝕刻區域.......................................47
圖4-11 彎曲波導及MMI漸變深蝕刻區域SEM圖.........................47

圖4-12 反射鏡面深蝕刻區域之OM圖.............................................49
圖4-13 反射鏡面深蝕刻區域之SEM圖...........................................49
圖4-14 移除蝕刻遮罩後之MMI SEM圖..........................................50
圖4-15 PI2562升溫曲線...................................................................52
圖4-16 以Dektak量測平坦化結果....................................................52
圖4-17 金屬掀離之後的OM圖.........................................................54
圖4-18 MBE_1.41μm被動元件之I-V曲線....................................56
圖4-19 被動元件量測系統架構圖......................................................57
圖4-20 直線波導共振傳輸光譜圖......................................................58
圖4-21 Bar端及Cross端的輸出訊號比例......................................58
圖4-22 光子濾波器量測結果..............................................................59











表目錄

表2-1 2×2 MMI之非均勻輸出功率.....................................................9
表4-1 MBE_1.41μm 磊晶片結構圖...................................................29
表4-2 ICP-RIE蝕刻條件.....................................................................44

參考文獻


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