850nm高速垂直共振腔面射型雷射之變溫特性研究

Abstract

本論文探討短波長850奈米紅外光垂直共振腔面射型雷射(Vertical Cavity Surface Emitting Laser)特性，包含磊晶結構設計、製程步驟、變溫光電直流特性分析、變溫高頻特性量測、小訊號模型分析、高頻特性磊晶結構和製程上優化。 第一章我們會先介紹光通訊的優勢及面射型雷射的發展背景和未來展望，探討850奈米短波常在光通訊上的應用和研究動機。 第二章我們會介紹面射型雷射基本原理和探討磊晶結構、製程步驟、變溫直流特性。磊晶結構我們針對量子井設計和共振腔設計這兩個方向做討論，接下來將介紹如何利用半導體的製程技術製作面射型雷射，最後針對製作出來的元件做變溫量測，探討5 μm、7 μm、9 μm、11 μm光孔徑大小元件在25 ℃、45 ℃、65 ℃、85 ℃下的直流特性，包含L-I-V曲線、L-J-V曲線、光頻譜分析，並深入了解元件直流特性對溫度的穩定性。 第三章我們將建立面射型雷射小訊號模型，由寄生電路模型和雷射本質物理模型組成。我們會先介紹電路模型中電路參數及和萃取方法，再由速率方程式 推導出雷射本質轉移函數，並了解本質函數中物理參數的意義及萃取方法。 第四章我們將分析5 μm、7 μm、9 μm、11 μm光孔徑大小元件在25 ℃、45 ℃、65 ℃、85 ℃下的高頻特性，針對其調變速度和能源效率做分析，再作眼圖和誤碼率的量測。最後萃取7 μm、9 μm、11 μm光孔徑大小元件在25 ℃、45 ℃、65 ℃、85 ℃下注入電流3,6,9 mA下的小訊號參數並分析電路及雷射本質高頻限制，由熱效應、阻尼效應、電路寄生效應三個面向作討論，最後探討如何優化磊晶結構及製程才能達到更快的調變速度。

The thesis focus on discussion of the characterization of the infrared 850 nm Vertical Cavity Surface Emitting Laser, including the layer structure design, process flow design, high temperature optical and electrical DC characterization, high temperature optical modulation characterization, small-signal model establishment and analysis, and modulation speed improvement form layer structure and process design. In Chapter one, the advantages of the optical communication and the background of the VCSEL will be introduced, then we discuss the application of the 850 nm VCSEL and the research motivation. In the Chapter two, first we will discuss the fundamental physics of the laser. Then, we research the layer structure, process flow, and high temperature DC characterization. We focus on the quantum well and cavity design of the layer structure, then introduce the fabrication of the VCSEL. In the last, we measure the DC characterization of the fabricated VCSELs with aperture diameter 5 μm、7 μm、9 μm、11 μm temperature ranging from 25 ℃ to 85 ℃ at 20 ℃ interval, and analyze the L-I-V curve, L-J-V cure, optical spectrum, and the temperature stability of the DC characterization. In Chapter there, we establish the small-signal model, including the parasitic electrical circuit model and physical intrinsic laser model. The electrical parameters in the circuit and the extraction method will be introduced. Then we derivate the laser intrinsic transfer function by rate equation, and recognize the meaning of the physical parameters and extraction method. In the Chapter four, we will analyze the modulation ability of the VCSELs with aperture diameter 7 μm、9 μm、11 μm temperature ranging from 25℃ to 85℃ at 20℃ interval, and put emphasis on the discussion of the modulation speed and energy-efficient ability. Then, we put the devices on the eye diagram and bit error rate test. At last, the small-signal parameters of the devices with aperture diameter 7 μm、9 μm、11 μm bias at 3, 6, 9 mA temperature ranging from 25 ℃ to 85 ℃ at 20 ℃ interval are extracted. Then, we analyze the modulation speed limitation by three aspects including thermal effect, damping effect, parasitic effect. At last but not least, we discuss how to improve the modulation speed by optimization of the layer structure and process flow.