| 摘要: | 對於多晶氧化鋅(ZnO)其本身電阻值高，因此一般於透明導電薄膜的應用上，則會將其摻雜Ш族元素（硼、鋁、鎵、銦等），使其導電特性提高，同時也增加其高溫穩定性。而在單晶氧化鋅(ZnO)是一種N型Ⅱ-Ⅵ族寬帶隙半導體材料，於可見光範圍內具有高穿透率，因為擁有與GaN相類似的特性，且激子束縛能高於GaN，有望取代GaN成為做紫外光LD和LED的材料。
本研究針對MOCVD近耦合噴淋式反對稱腔體進行熱場、流場及物種傳輸模擬研究。起初，依照生長ZnO薄膜的化學反應式，建立表面吸附模型，比較不同吸附物種與化學反應式對於ZnO薄膜生長效率之影響，將10條氣相化學反應式簡化為3條主要化學反應式。
本腔體的設計中，考量透明導電膜為方形，因此針對方形薄膜設計方形反應腔體，而大型玻璃載盤轉動困難，以反對稱進氣孔交錯的方式來達到物種沉積均勻的效果。同時探討改變製程參數對表面吸附效率與薄膜生長變化率之影響，ZnO薄膜生長效率會隨著製程壓力增加而升高，隨著溫度改變的生長率當壓力增大斜率也越大，另外，ZnO薄膜生長效率，隨著壓力改變的生長率當製程溫度增大斜率也越大，流量增加時，ZnO薄膜生長效率會提高，但流量到達一定的倍數並不會增加長率，進氣孔徑擴大，生長效率會提高，但孔徑到達一定的數值並不會提升生長效率，本研究將三個抽氣孔半徑於設定範圍內參數掃描，以便達到ZnO薄膜生長變化率最小值，模擬研究結果為上方抽氣孔20mm、中間抽氣孔35mm與下方抽氣孔25mm會有最低的生長變化率為0.0802%。
;polycrystalline zinc oxide has a high resistance value, so generally, in the application of a transparent conductive film, it is doped with Ш elements (boron, aluminum, gallium, indium, etc.) to improve its conductivity and also improve its conductivity. Increase its high temperature stability.However, Single crystal zinc oxide (ZnO) is an N-type II-VI wide band gap semiconductor material with high transmittance in the visible range. It has similar properties to GaN and exciton binding energy is higher than GaN. Substituting GaN has become a material for UV LDs and LEDs .
In this study, the thermal field, flow field and species transfer simulation of MOCVD near-coupled spray-type anti-symmetric cavity were studied. At first, according to the chemical reaction formula of the grown ZnO thin film, a surface adsorption model was established to compare the effects of different adsorbed species and chemical reaction formulas on the growth efficiency of ZnO thin films. Ten gas phase chemical reaction schemes were simplified into three main chemical reaction formulas.
In the design of the cavity, the transparent conductive film is considered to be square. Therefore, a square reaction cavity is designed for the square film, and the large glass carrier is difficult to rotate, and the effect of uniform deposition of the species is achieved by opposing the staggered inlet holes. At the same time, the effect of changing process parameters on surface adsorption efficiency and film uniformity is discussed. The growth efficiency of ZnO thin film increases with the increase of process pressure. The growth rate increases with temperature and the slope increases with pressure. In addition, ZnO thin film growth efficiency, growth rate with pressure change When the process temperature increases, the slope increases; the flow rate increases, the growth efficiency of ZnO thin film increases, but the flow rate reaches a certain multiple does not increase the long rate; the inlet pore size increases, and the growth efficiency will increase, but the aperture reaches a certain value does not improve the growth efficiency. In this study, the parameters of the three venting radii within the set range are scanned to achieve the minimum error of the ZnO film uniformity. The simulation result is 20mm above the hole. The lowest uniformity error of the upper uniform hole 20mm, the middle suction hole 35mm and the lower suction hole 25mm will have the lowest uniformity error of 0.0802%. |
