多孔石墨对碳化硅晶体生长影响的数值模拟研究  

Influence of Porous Graphite on SiC Crystal Growth:a Numerical Simulation Study

作　　者：李荣臻 赵小玻 魏华阳 李丹[2] 周振翔[2] 倪代秦[2] 李勇[3] 李宏凯 林清莲 LI Rongzhen;ZHAO Xiaobo;WEI Huayang;LI Dan;ZHOU Zhenxiang;NI Daiqin;LI Yong;LI Hongkai;LIN Qinglian(Sinoma Synthetic Crystals(Shandong)Co.,Ltd.,Jinan 250200,China;Beijing Sinoma Synthetic Crystals Co.,Ltd.,Beijing 100018,China;Sinoma High-Tech Materials Co.,Ltd.,Beijing 100021,China)

机构地区：[1]中材人工晶体研究院(山东)有限公司,济南250200 [2]北京中材人工晶体研究院有限公司,北京100018 [3]中材高新材料股份有限公司,北京100021

出　　处：《人工晶体学报》2023年第12期2174-2185,共12页Journal of Synthetic Crystals

摘　　要：SiC是新一代射频器件和功率器件的理想材料,电阻式物理气相传输法由于具有温度均匀性,成为生长大尺寸SiC单晶的有效方法。近年来,多孔石墨等的使用提高了SiC晶体的质量和产量,而关于其机理的研究却相对较少。本文使用数值模拟的方法系统研究了多孔石墨对SiC晶体生长的影响,并进行了晶体生长验证。模拟结果表明:多孔石墨的使用提高了原料区域的温度及温度均匀性,增大了坩埚内轴向温差,对减弱原料表层的重结晶也具有一定作用;在生长腔内,多孔石墨改善了物质流动在整个生长过程中的稳定性,提高了生长区域的C/Si比,有助于减小相变发生概率,同时多孔石墨对晶体界面也起到改善作用。晶体生长结果实际验证了多孔石墨在提高传质均匀性、降低相变发生率和改善晶体外形上的作用。本文结果对于理解多孔石墨的作用机理以及改善SiC晶体生长条件具有实际意义。SiC is the ideal material for RF devices and power devices.Resistance-heated physical vapor transport method is considered a promising way to grow large size(especially 6 and 8 inch)SiC crystals due to its temperature uniformity.In recent years,the introduction of new technique such as the use of porous graphite improved the SiC crystal quality and yield,while there are only a few relatively comprehensive studies on its mechanism.This paper made comprehensive research on the influence of porous graphite on SiC growth system by means of numerical simulation.The crystal growth experiments under numerical simulation conditions have been carried out accordingly.The numerical simulation results show that the porous graphite raises the temperature and temperature uniformity within the powder area,which can strengthen the sublimation of powder.The temperature difference between the powder and the seed inside the crucible is improved and a greater growth driving force is obtained.The effect of decrease of the re-crystallization at powder surface has also been proved.Besides,the porous graphite improves the flow stability across the whole growth process,and assures a stable crystal growth.The C/Si ratio has been increased under the influence of porous graphite,and thus reduces the probability of phase transition.The crystal shape has also been improved.The subsequent growth experiments verified the conclusions of numerical simulations such as the improvement of flow uniformity,decrease of poly-type transition probability,improvement of crystal shape,etc.The results of this paper have practical significance on comprehending the effecting mechanism of porous graphite and improving the SiC crystal growth conditions for better crystal quality.

关 键 词：碳化硅 多孔石墨 数值模拟 晶体生长 电阻加热 物理气相传输 

分 类 号：O782[理学—晶体学]