本文選題：氫化物氣相外延 + GaN�。� 參考：《南京郵電大學(xué)》2015年碩士論文

【摘要】：本文基于計算流體力學(xué)(CFD)原理,運用流體力學(xué)相關(guān)知識,采用有限元分析軟件對自制的立式氫化物氣相外延(HVPE)系統(tǒng)制備GaN材料進(jìn)行了數(shù)值模擬研究。采用CFD軟件模擬GaN的生長一方面能夠有效節(jié)省實驗成本,為制備高質(zhì)量GaN的腔體優(yōu)化提供優(yōu)化基礎(chǔ),另一方面可以不受傳統(tǒng)熱力學(xué)和動力學(xué)機制的束縛,預(yù)測整個襯底上方GaN的生長情況,對實際過程中對GaN的生長有一定指導(dǎo)意義。對反應(yīng)氣體出氣管口到襯底的距離是否影響襯底上方GaCl和NH3的摩爾濃度分布進(jìn)行了二維模擬計算。通過設(shè)定多組實驗?zāi)Ｐ?不同模型中襯底到出氣口距離并不相同,對比不同距離下GaN的生長速率和均勻性的對比來得到最佳距離。通過對比得到當(dāng)襯底高度15mm時有利于反應(yīng)氣體的分布。通過建立二維模型來研究出氣管口口徑大小的改變是否影響襯底上方GaCl的摩爾濃度分布、NH3的摩爾濃度分布和Ga N的生長情況。整個優(yōu)化過程分為兩步,首先設(shè)定N2的內(nèi)徑是固定的,改變NH3和GaCl的出氣口內(nèi)徑大小來得到一組最優(yōu)化解,然后單獨改變N2的出口內(nèi)徑來得到N2的最后化解。通過計算分析得到當(dāng)GaCl的出口內(nèi)徑為12mm、NH3出口的內(nèi)徑為43mm和N2出氣口內(nèi)徑為76mm時,此時得到GaN薄膜均勻性得到了很大提高。單獨調(diào)整GaCl出氣管口到襯底的距離來進(jìn)一步優(yōu)化腔體。當(dāng)GaCl出氣管口距離襯底過近時會阻擋一部分NH3在襯底中間位置的擴散,當(dāng)距離過遠(yuǎn)時,會使一部分NH3擴散到GaCl出氣管口,這兩種情況對于GaN的生長是十分不利的。設(shè)置不同的GaCl出氣管口到襯底距離來分析對應(yīng)GaN的生長情況,通過模擬計算得到當(dāng)GaCl出氣管口到襯底的距離為17mm時此時均勻性得到進(jìn)一步提高,相對均勻性達(dá)到4.2%。
[Abstract]:Based on the principle of computational fluid dynamics (CFD) and using the knowledge of hydrodynamics, the finite element analysis software is used to simulate the preparation of the self-made vertical hydride vapor phase epitaxy (HVPE) system for the preparation of GaN materials. Using CFD software to simulate the growth of GaN, the experimental cost can be effectively saved and the cavity of high quality GaN is prepared. Optimization provides the basis for optimization. On the other hand, the growth of GaN above the whole substrate can be predicted without the constraints of traditional thermodynamics and dynamics. It has certain guiding significance for the growth of GaN in the actual process. Whether the distance between the outlet of the gas outlet tube and the substrate affects the molar concentration distribution of the GaCl and NH3 above the substrate. Two dimensional simulation calculation. By setting a number of experimental models, the distance between the substrate and the outlet is not the same in the different models. The optimum distance is obtained by comparing the growth rate and uniformity of GaN under different distances. By contrast, the distribution of the reaction gas is favorable when the height of the substrate is 15mm. A two-dimensional model is established to study the trachea. Whether the change of the size of the aperture affects the molar concentration distribution of GaCl above the substrate, the distribution of the molar concentration of NH3 and the growth of Ga N. The whole optimization process is divided into two steps. First, the internal diameter of N2 is fixed, and the size of the outlet diameter of NH3 and GaCl is changed to get a group of optimal solutions, and then the exit inner diameter of N2 is changed separately. To the final resolution of N2, it is obtained that when the internal diameter of the GaCl is 12mm, the inner diameter of the NH3 outlet is 43mm and the inner diameter of the N2 outlet is 76mm, the uniformity of the GaN film is greatly improved at this time. The distance of the GaCl outlet pipe to the substrate is further optimized. When the GaCl exits are too close to the substrate, the GaN film will be more close to the substrate. Blocking a part of the diffusion of NH3 in the middle of the substrate, when the distance is too far, will spread a part of the NH3 to the outlet of the GaCl outlet. These two cases are very unfavorable to the growth of GaN. Set the different GaCl outlet to the substrate distance to analyze the growth of the corresponding GaN, through the simulation calculation, when the outlet of the GaCl outlet pipe to the substrate is obtained. When the distance is 17mm, the homogeneity is further improved and the relative homogeneity is 4.2%..
【學(xué)位授予單位】：南京郵電大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號】：TN304.05

【相似文獻(xiàn)】

相關(guān)期刊論文 前10條

1 修向前,張榮,盧佃清,顧書林,沈波,施毅,鄭有p，

本文編號：1928143