氮化铝单晶PVT同质外延生长工艺三维各向异性应力和位错模拟仿真技术开发及其实验研究
结题报告
批准号:
61874071
项目类别:
面上项目
资助金额:
16.0 万元
负责人:
wuliang
依托单位:
学科分类:
F0401.半导体材料
结题年份:
2019
批准年份:
2018
项目状态:
已结题
项目参与者:
张振强、李霞、赵寅廷、王琦琨、王智昊、贺广东、雷丹、黄嘉丽
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中文摘要
本项目将基于申请人开发的瞬态温度场并根据弹塑性有限元基本理论,开发氮化铝单晶同质外延生长工艺条件下的三维各向异性应力有限元通用计算算法与模块。同时扩展现有非线性固体Alexander-Haasen (AH)理论模型,开发AlN单晶生长过程、冷却过程中瞬时三维位错密度预测算法与模块,预测晶体生长及冷却过程中的位错增殖速率、位错密度及残余应力分布。基于以上开发模块,对自主设计的AlN单晶PVT生长设备、热场及同质外延生长工艺进行优化(特别是坩埚内部优化设计),以期控制位错的产生、增殖,从而降低氮化铝单晶位错密度。基于优化的热场及其工艺,开展不同晶向衬底的同质外延生长实验及材料表征,并与模拟结果进行对比、分析与验证,掌握氮化铝单晶同质外延生长过程三维各向异性应力、位错分布规律及控制途径与优化方向,指导低位错、高质量、无裂纹氮化铝单晶同质外延生长工艺。
英文摘要
Due to its wide bandgap, high breakdown field and high thermal conductivity, AlN is an excellent candidate for high-temperature, high-frequency, high-power electronic and deep-UV optoelectronic devices. The PVT method has been shown to be very a promising technique for the growth of large high-quality bulk AlN crystals. Currently, high-quality and crack-free AlN crystals up to 1-2 inches in diameter grown by the PVT method are available with very limited volume. ..Large-size AlN single crystals with high structural quality can only be grown the homoepitaxial PVT growth. Nevertheless, single crystalline AlN boules obtained by the homoepitaxial seeded PVT growth normally have heterogeneously distributed defects, such as basal plane dislocations (BPDs), thread edge dislocations (TEDs), and low angle grain boundaries (LAGBs). BPDs are generated during crystal growth due to thermal stresses, while TEDs are grown-in defects replicated from the seed. High dislocation densities in the active layers (derived from the AlN substrates) of optoelectronic devices show an adverse effect on their internal quantum efficiency, and accordingly strongly affect the performance, reliability and lifetime of the devices grown on AlN substrates. Therefore, the thermal-elastic stresses in growing AlN crystals should be minimized as much as possible to reduce the generation and multiplication of BPDs. ..In this proposal, a 3D thermal-elastic stress model using the Finite Element Method (FEM) to predict anisotropic thermal stress in AlN single crystals homoepitaxially grown by the physical vapor transport growth process will be developed, and the von Mises stress, resolved shear stress and total shear stress along primary slip system will be computed accordingly in order to qualitatively evaluate the dislocation density in the growing crystal based on critical resolved shear stress (CRSS model). In the meantime, Alexander-Haasen (AH) FEM model to predict the 3D distribution of dislocation density in the AlN crystal will be developed based on dynamical global heat transfer taking into account radiation, conduction and convection into account. Hotzone optimization for homoepitaxial AlN single crystal growth will be performed in order to reduce the dislocation density in the growing crystal through numerical experiments. Physical experiments by the Homoepitaxial AlN seeded PVT growth and material characterization will also be arranged to validate the developed 3D thermal stress and dislocation model.
PVT 法由于具有生长速率快、结晶完整性好、安全性高、适合生长块状高质量衬底材料等优点被认为是制备大尺寸、高质量AlN 晶体最有前途的方法。但通过PVT方法生长的AlN单晶晶锭通常具有不均匀分布的各种缺陷,如基底位错(BPD)、穿线位错(TED)以及小角度晶界(LAGB)。BPD 是由晶体中径向温度梯度诱发的位错,且BPD 的产生和增殖主要是由晶体生长过程中沿着主滑移方向产生的剪应力引起的。因此,生长AlN 晶体时的热弹性应力应尽可能低,以减少BPD 的产生和增殖,并抑制裂纹的产生与扩展。.. 在本项目的资助下,本项目组基于热弹塑性理论,系统开展了AlN 单晶PVT 同质外延生长过程中的三维各向异性应力和位错模拟仿真技术理论开发及其实验研究,包括在世界上首次成功开发出了AlN 单晶生长三维各向异性应变及应力有限元算法计算各模块,如VMS(Von-Mises)应力有限元模块、RSS(Resolved Shear Stress) 有限元模块、TRSS(Total Resolved shear stress)有限元模块等。同时,本项目组利用开发的相关模块,对自主设计的AlN单晶PVT生长设备、热场及同质外延生长工艺进行分析、优化,大幅降低了AlN单晶生长过程的热应力;基于优化的工艺开展了AlN单晶生长工艺实验及其材料表征研究,成功解决了由于AlN单晶生长过程中的过大应力导致晶体的开裂与寄生形核。基于本项目研究成果,项目组成员在2019年内在国内外期刊上发表期刊论文4篇(其中国外SCI两篇),会议论文2篇,培养研究生3名,圆满完成了该项目的研究计划。
期刊论文列表
专著列表
科研奖励列表
会议论文列表
专利列表
DOI:--
发表时间:2019
期刊:人工晶体学报
影响因子:--
作者:贺广东;王琦琨;雷丹;龚建超;黄嘉丽;付丹扬;吴亮
通讯作者:吴亮
DOI:10.1016/j.jcrysgro.2019.04.032
发表时间:2019-08-01
期刊:JOURNAL OF CRYSTAL GROWTH
影响因子:1.8
作者:Wang, Qikun;Zhao, Yinting;Wu, Liang
通讯作者:Wu, Liang
DOI:--
发表时间:2019
期刊:半导体光电
影响因子:--
作者:雷丹;王琦琨;黄嘉丽;贺广东;龚建超;付丹扬;吴亮
通讯作者:吴亮
Influence of crucible shape on mass transport in AlN crystal growth by physical vapor transport process
坩埚形状对物理气相传输过程生长 AlN 晶体质量传输的影响
DOI:10.1016/j.jcrysgro.2019.02.059
发表时间:2019-06-01
期刊:JOURNAL OF CRYSTAL GROWTH
影响因子:1.8
作者:Wang, Qikun;Huang, Jiali;Wu, Liang
通讯作者:Wu, Liang
国内基金
海外基金