噴灑頭式及行星式MOCVD反應器之性能數值模擬分析

Abstract

本文利用計算流體力學(Computational Fluid Dynamics)數值方法來分析噴灑頭式反應器(showerhead)和行星式反應器(planetary)內金屬有機化學氣相沉積(MOCVD)之熱流場與化學反應變化。透過商用軟體ANSYS FLUENT來模擬固態電子材料氮化鎵(GaN)在反應器內熱流場以及晶圓表面的化學沉積速率。噴灑頭式反應器的模擬結果顯示當承載盤轉速上升時，有助於GaN獲得更好得均勻度，另一方面，GaN的沉積速率隨著NH3流量增加而呈現先上升後下降的趨勢，並且隨著TMGa流量增加呈現線性上升，而當五三族氣體比例值小時，GaN的沉積速率隨著五三族氣體比例值稍微改變而有劇烈變化。行星式反應器的模擬結果顯示放置在承載盤上的晶柱隨著轉動改變位置時，越靠近承載盤中心的區域的晶柱上GaN的沉積速率越低，不過當熱流場隨著時間增加趨近穩定時，晶柱上GaN膜厚也會呈現均勻對稱分佈，綜上所述，本研究以計算流體力學可成功解出有機化學氣相沉積之結果，對於半導體製程之最佳化有極大的成就。

Computational fluid dynamics (CFD) is used in this study to analyze and design the chemical vapor deposition (CVD) reactors. CFD commercial software: ANSYS FLUENT is used to calculate fluid flow, heat transfer and species transport in showerhead and planetary type chambers. For showerhead type reactor, the results show that higher rotation speed provides better flow distribution and more uniform deposition rate. Besides, the GaN growth rate rises in the beginning then falls as the NH3 flow rate increases and also linearly proportional to the TMGa flow rate. Furthermore, the GaN growth rate changes dramatically by slightly changing the Ⅴ/Ⅲ ratio in low Ⅴ/Ⅲ ratio inlet condition. Based on the results in planetary type reactor, the GaN growth rate become higher while the crystal column is closer to the center of the susceptor. However, when the thermal and flow field become steady state, the GaN growth rate of the crystal column also becomes uniform. Therefore, this study successfully solved the chemical vapor deposition problems by CFD and have huge achievement of optimization in semiconductor manufacture.