| 摘要: | 有機金屬化學氣相沉積法為目前製作LED最重要的技術之一，根據不同種類的薄膜材料，如單晶、非晶等磊晶材料進行沉積製程。本研究使用商用軟體COMSOL分析Veeco D-180 GaN腔體建立三維數值模擬模型，採用入口狹縫方式探討不同進氣流量、腔體壓力以及載台轉速之操作製程參數對腔體內部熱流場與薄膜成長率和均勻性的影響，接著對腔體幾何入口的數量與腔體高度做改善，結果顯示入口數量為15條，腔體高度為110 mm時，能夠達到較好的薄膜生長速率與均勻性。最後，藉由優化入口設計以得到更佳的氣體利用率與薄膜成長的均勻性結果，結果顯示同心軸垂直雙狹縫與入口間檔板設計能有效的提高反應物種濃度混合從而達到更好的均勻性。
本論文亦以實驗觀測與分析方式，對可視化反應腔體中基板在高溫變化下，藉由改變不同的單孔進氣流量、腔體壓力，探討反應腔內的熱流場分佈情形。其中，透過可視化實驗量測取得一系列的流場動態圖，再利用Particle Image Velocimetry（PIV）影像分析軟體與Matlab進行後處理速度場分析，結果顯示，在單孔進氣下，高溫反應腔體產生的熱浮力效應明顯影響載台上流動邊界層的變化，以及製程參數改變也會對流場渦流的情形，兩者流場變化皆嚴重影響磊晶沉積速率與均勻度。最後利用數值模擬方法與實驗結果相互比較，並得到初步吻合的結果。
;Metal-Organic Chemical Vapor Deposition, MOCVD, is one of the most important technologies to manufacture the LED. Depending on the type of film material, such as a single crystal, amorphous materials and other epitaxial deposition process. In this study, the computer simulation (COMSOL) method to develop the three-dimensional numerical simulation model. The numerical parameter will involve the inlet flow rate, the chamber pressure, the susceptor rotation rate, use the thermal-flow field and the species concentration to realize the mechanism between the growth rate and the uniformity of film, also compare with paper to define the ture model. After that, design of the basic geometry and then the study of number of the inlets and the chamber height was done. The result presents the that when the inlets is 15, height is 110mm, the film growth rate and uniformity is better. Finally, the study of optimization of the slit inlets was done. The results shows the gas inlet design with the double concentric vertical and the barrier of inlet will improve uniformity of the concentration of reactive species and uniform region on the susceptor to improve the problem of the low gas-usage.
This study also applied experimental method to the flow field of the visualization of the reaction chamber was experimentally measured. There are several experimental parameters which affect the chamber thermal flow and stability, such as susceptor temperature, inlet flow rate, and chamber pressure. In order to observe the thermal flow and velocity distribution in the chamber, Time-Resolved Digital Particle Image Velocimetry Tool for MATLAB, PIVlab was used as the flow visualization technique. The result shows that in the single jet chamber, use the dimensionless number (Re, Gr) to realize the mechanism between the force convection and the natural convection, then both the flow field are seriously affecting the film deposition rate, uniformity. Finally, using numerical simulation and experimental results do compare, resulting consistent need to make improvements and modifications. |
