| 摘要: | MOCVD(metal organic chemical vapor deposition )為製作LED磊晶片重要的設備，其中，關鍵零組件進氣擴散系統透過噴嘴(nozzle)或是噴氣頭(showerhead)的方式，將氣體送入反應腔體進行氣體混合和化學反應。本文是使用計算流體力學軟體Fluent針對Veeco E300腔體進行模擬分析，研究內容可以分成二個部分：第一部分為探討製程參數：進氣流率、腔體壓力、載台轉速、壁面溫度、進氣口與載台距離及探討出口最佳位置和角度，以上的模擬結果與將與文獻的結果相比較，已確認模型的準確性。第二部分則以建立的腔體熱流場為基礎，在進氣擴散系統下方設計－進氣擋板，進氣檔板能增加了進氣擴散系統進氣排列的變化性，能有效隔絕氣體進入腔體時就產生混合，造成進氣孔的阻塞，本文為針對檔板長度、檔板幾何外型、傾斜角度、三五族金屬源比例等對腔體熱流場的影響進行研究並找出最佳的設計且進行三維模型驗證，結果發現最佳設計為在檔板傾斜角度35?時對於成長速率和TMGa濃度均勻性皆有明顯的改善，證明此進氣擴散系統能達到高均勻度的磊晶薄膜，並能有效減少MO氣體的使用量。
MOCVD is one of the most important equipment and widely used for the epitaxial growth of LED wafers. The key component “gas injection system” was sent the gas into the reactor by using the nozzle or the showerhead .which happen chemical reaction and gas mixing .In this paper ,we use the computer simulation (Fluent) method to investigate the VEECO E300 chamber’s thermal flow and design the new gas injection system. The numerical parameter will involve the inlet flow rate ,the chamber pressure, the susceptor rotation rate ,the wall temperature ,the distance between inlet and susceptor ,outlet location, outlet degree ,we use the dimensionless number(Re, Gr, Rew) to realize the mechanism between the force convection and the natural convection, then improve the flow uniformity, beside, we also compare with paper to define the ture model.
According to this basic thermal flow model for ,we design the “inlet barrier” under the gas injection system, inlet barrier can obstruct the different reaction gas ,reduce the pre-reaction and deposit particle on the wall. the numerical parameter are the barrier length ,the barrier geometry, the barrier incline degree, and the V/III precursor ratio, it is found that the increase of the barrier’s length has reduce the small recirculation between the barrier, the best barrier design(barrier incline degree 35?) not only increases the growth rate ,but also improves the concentration uniformity, we proved that the barrier really decreases the MO gase’s usage. |
