反應(yīng)動力學(xué)參數(shù)變化對MOVPE生長GaN的反應(yīng)路徑模擬的影響
發(fā)布時間：2019-05-16 17:22
【摘要】：在金屬有機(jī)化學(xué)氣相外延(MOVPE)生長GaN薄膜的反應(yīng)-輸運過程數(shù)值模擬中,反應(yīng)動力學(xué)參數(shù)(活化能和指前因子)的選取存在很大的不確定性,從而導(dǎo)致不同的氣相反應(yīng)路徑和生長速率.本文對前人采用的反應(yīng)動力學(xué)參數(shù)的偏差做了歸納總結(jié),討論了偏差的來源.在此基礎(chǔ)上,本文對垂直轉(zhuǎn)盤式MOVPE反應(yīng)器生長GaN的反應(yīng)-輸運過程進(jìn)行數(shù)值模擬研究.模擬改變不同的反應(yīng)動力學(xué)參數(shù)組合,包括加合物的生成和可逆分解的指前因子、加合物不可逆分解生成氨基物的活化能和指前因子以及三聚物生成的指前因子.通過分析主要含Ga物質(zhì)的摩爾濃度和對應(yīng)的生長速率的變化,研究上述反應(yīng)動力學(xué)參數(shù)變化對GaN生長反應(yīng)路徑的模擬結(jié)果的影響.研究的主要結(jié)論如下:(1)不同的指前因子和活化能導(dǎo)致不同的反應(yīng)路徑和生長速率的差異,而熱解路徑比起加合路徑能夠更有效地提高生長速率.(2)在不考慮三聚物反應(yīng)時,預(yù)測的生長速率值都與實驗值接近.原因在于,輸運限制的生長速率取決于含Ga粒子的輸運速率,不同的反應(yīng)路徑對含Ga粒子的影響此消彼長,但到達(dá)襯底的含Ga粒子的總量變化不大,這也很好地解釋了不同文獻(xiàn)采用不同的動力學(xué)參數(shù)模擬都與實驗基本吻合的原因.(3)改變?nèi)畚锓磻?yīng)的指前因子發(fā)現(xiàn),由于熱泳力對大分子的排斥作用,三聚物對生長的貢獻(xiàn)很小,生成的三聚物越多,與實驗的誤差越大.模擬結(jié)果澄清了前人在模擬MOVPE生長GaN的反應(yīng)-輸運過程中存在的一些問題,并加深了對GaN生長機(jī)理的了解.
[Abstract]:In the numerical simulation of reaction-transport process of GaN thin films grown by metal organic chemical vapor phase epitaxial (MOVPE), there is great uncertainty in the selection of reaction kinetic parameters (activation energy and preexponential factor). This leads to different gas phase reaction paths and growth rates. In this paper, the deviation of the reaction kinetic parameters adopted by the predecessor is summarized, and the source of the deviation is discussed. On this basis, the reaction-transport process of GaN growth in vertical turntable MOVPE reactor was studied by numerical simulation. Different combinations of reaction kinetic parameters were simulated, including the formation of adduct and the pre-exponential factor of reversible decomposition, the activation energy and preexponential factor of irreversible decomposition of adduct to amino substance, and the preexponential factor of trimer formation. By analyzing the molar concentration of Ga and the corresponding growth rate, the effect of the above kinetic parameters on the simulation results of GaN growth path was studied. The main conclusions are as follows: (1) different preexponential factors and activation energy lead to different reaction paths and growth rates. The pyrolysis path can increase the growth rate more effectively than the addition path. (2) when the trimer reaction is not considered, the predicted growth rate is close to the experimental value. The reason is that the growth rate of transport restriction depends on the transport rate of Ga particles, and the influence of different reaction paths on Ga particles increases or decreases, but the total amount of Ga particles arriving on the substrate does not change much. This also explains why the simulation of different kinetic parameters in different literatures is basically consistent with the experiment. (3) it is found that due to the rejection of macromolecules due to the repulsive effect of thermal swimming force, it is found that the preexponential factor of trimer reaction is changed. The contribution of trimer to growth is very small, and the more trimer is formed, the greater the error with the experiment. The simulation results clarify some problems existing in the reaction-transport process of simulating the growth of GaN by MOVPE, and deepen the understanding of the growth mechanism of GaN.
【作者單位】： 江蘇大學(xué)能源與動力工程學(xué)院;
【基金】：國家自然科學(xué)基金(批準(zhǔn)號:61474058) 江蘇省普通高校研究生科研創(chuàng)新計劃(批準(zhǔn)號:CXLX11_0573)資助項目
【分類號】：TN304.2
，
本文編號：2478440
[Abstract]:In the numerical simulation of reaction-transport process of GaN thin films grown by metal organic chemical vapor phase epitaxial (MOVPE), there is great uncertainty in the selection of reaction kinetic parameters (activation energy and preexponential factor). This leads to different gas phase reaction paths and growth rates. In this paper, the deviation of the reaction kinetic parameters adopted by the predecessor is summarized, and the source of the deviation is discussed. On this basis, the reaction-transport process of GaN growth in vertical turntable MOVPE reactor was studied by numerical simulation. Different combinations of reaction kinetic parameters were simulated, including the formation of adduct and the pre-exponential factor of reversible decomposition, the activation energy and preexponential factor of irreversible decomposition of adduct to amino substance, and the preexponential factor of trimer formation. By analyzing the molar concentration of Ga and the corresponding growth rate, the effect of the above kinetic parameters on the simulation results of GaN growth path was studied. The main conclusions are as follows: (1) different preexponential factors and activation energy lead to different reaction paths and growth rates. The pyrolysis path can increase the growth rate more effectively than the addition path. (2) when the trimer reaction is not considered, the predicted growth rate is close to the experimental value. The reason is that the growth rate of transport restriction depends on the transport rate of Ga particles, and the influence of different reaction paths on Ga particles increases or decreases, but the total amount of Ga particles arriving on the substrate does not change much. This also explains why the simulation of different kinetic parameters in different literatures is basically consistent with the experiment. (3) it is found that due to the rejection of macromolecules due to the repulsive effect of thermal swimming force, it is found that the preexponential factor of trimer reaction is changed. The contribution of trimer to growth is very small, and the more trimer is formed, the greater the error with the experiment. The simulation results clarify some problems existing in the reaction-transport process of simulating the growth of GaN by MOVPE, and deepen the understanding of the growth mechanism of GaN.
【作者單位】： 江蘇大學(xué)能源與動力工程學(xué)院;
【基金】：國家自然科學(xué)基金(批準(zhǔn)號:61474058) 江蘇省普通高校研究生科研創(chuàng)新計劃(批準(zhǔn)號:CXLX11_0573)資助項目
【分類號】：TN304.2
，
本文編號：2478440
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