PVT同质外延生长AlN单晶初期模拟及其实验研究

Numerical Simulation and Experimental Research on AlN Crystal Initial Growth by Homoepitaxial PVT Method

摘要:

在同质外延生长大尺寸、高质量氮化铝单晶的初期,常用梯度反转工艺避免氧、碳及氢等杂质污染籽晶表面。本文使用FEMAG晶体生长模拟仿真软件及自主开发的PVT法有限元多相流传质模块对自主设计的全自动、双电阻加热气相沉积炉进行了同质外延生长AlN单晶初期温度场及传质过程模拟仿真研究,并基于模拟结果开展了同质外延长晶实验。模拟仿真及实验研究结果表明：通过生长初期的梯度反转工艺可有效消除氧、碳及氢等杂质表面污染；坩埚的合理位置对同质外延生长AlN单晶时的温度梯度、Al/N蒸气传输及生长速率等至关重要；基于AlN单晶同质外延生长初期的模拟仿真研究与成功生长实验,为下一步开展稳定同质外延扩尺寸单晶生长工艺奠定了扎实基础。

Abstract:

An inverse temperature gradient is generally adopted in order to avoid second nucleation at the initial homoepitaxial growth due to O, C and H impurities. In this paper, we investigated the temperature distribution and mass transfer at the initial homoepitaxial AlN growth stage in a proprietary and fully automatic physical vapor transport sublimation reactor by FEMAG and an in-house finite element multi-phase mass transfer code, respectively. Homoepitaxial growth experiment was also conducted successfully based on numerical simulation results. The simulation and experiment results showed the deposition of O, C and H impurities at the initial homoepitaxial growth stage could be efficient avoided by an inverse temperature distribution. The crucible position played a key role on the temperature distribution and mass transfer during the subsequent AlN crystal growth stage. The numerical simulation results and successful homoepitaxial growth experiment placed a solid foundation for our future size enlargement growth experiments.