Choice of crucible material is a key issue during the growth of AIN crystal. The stabilities at high temperature and life-spans of boron nitride （BN） crucible, tantalum （Ta） crucible and tungsten （W） crucible we...Choice of crucible material is a key issue during the growth of AIN crystal. The stabilities at high temperature and life-spans of boron nitride （BN） crucible, tantalum （Ta） crucible and tungsten （W） crucible were compared. Tantalum crucible behaved worse at high temperature and life-span was shortened as compared with the other two crucible materials. It was very crisp and easy to crack. In contrast, self-seeded AIN crystals with different morphologies could be obtained at different high temperatures using BN crucible. The boron nitride crucible was stable below 2200 ℃, above which it would decompose. Thus it was unsuitable for the bulky AIN crystal growth. Tungsten crucible could endure the temperatures higher than 2200℃. Unfortunately we could only get AIN polycrystallines using tungsten crucible. After 50- 100 hours＇ run, the crucible was destroyed completely due to the multiple deep cracks. XRD results of destroyed tungsten crucible indicated that the main phases are tungsten carbide and tungsten nitride.展开更多
A lN是一种重要的半导体材料,由于具有宽带隙、高临界击穿电场、高热导率、高载流子饱和漂移速度等优越的特性,在微电子和光电子领域具有广泛的应用前景。本文综述了国际上A lN单晶生长的研究进展,对其结构特点、生长方法的选择、生长...A lN是一种重要的半导体材料,由于具有宽带隙、高临界击穿电场、高热导率、高载流子饱和漂移速度等优越的特性,在微电子和光电子领域具有广泛的应用前景。本文综述了国际上A lN单晶生长的研究进展,对其结构特点、生长方法的选择、生长过程中的问题及存在的结构缺陷等方面进行了介绍。展开更多
AlN whiskers or dendrites were synthesized with asublimation-recrystallization method by using Al, AlN powders and some additives as raw materials.Whiskers with different sizes that featured high purity and good cryst...AlN whiskers or dendrites were synthesized with asublimation-recrystallization method by using Al, AlN powders and some additives as raw materials.Whiskers with different sizes that featured high purity and good crystallinity were obtained bycontrolling temperature and gas supersaturation in the reaction container. The whiskers weredescribed as long and straight single crystals of approximately 1-30 mu m in diameter by thecentimeter range in length. However, AlN dendrites were about 1mm in diameter by 0.5cm in length,and showed an obviously preferential growth orientation, i.e., perpendicular to [21-bar1-bar1] and[101-bar1] planes. It is concluded that the whiskers or dendrites grow via the vapor-solidmechanism.展开更多
基金the National Natural Science Foundation of China (No. 50472068)the Program for New Century Excellent Talents in University
文摘Choice of crucible material is a key issue during the growth of AIN crystal. The stabilities at high temperature and life-spans of boron nitride （BN） crucible, tantalum （Ta） crucible and tungsten （W） crucible were compared. Tantalum crucible behaved worse at high temperature and life-span was shortened as compared with the other two crucible materials. It was very crisp and easy to crack. In contrast, self-seeded AIN crystals with different morphologies could be obtained at different high temperatures using BN crucible. The boron nitride crucible was stable below 2200 ℃, above which it would decompose. Thus it was unsuitable for the bulky AIN crystal growth. Tungsten crucible could endure the temperatures higher than 2200℃. Unfortunately we could only get AIN polycrystallines using tungsten crucible. After 50- 100 hours＇ run, the crucible was destroyed completely due to the multiple deep cracks. XRD results of destroyed tungsten crucible indicated that the main phases are tungsten carbide and tungsten nitride.
基金This work was financially supported by the National Natural Science Foundation of China(No 59872004), the Cross-Century Talents
文摘AlN whiskers or dendrites were synthesized with asublimation-recrystallization method by using Al, AlN powders and some additives as raw materials.Whiskers with different sizes that featured high purity and good crystallinity were obtained bycontrolling temperature and gas supersaturation in the reaction container. The whiskers weredescribed as long and straight single crystals of approximately 1-30 mu m in diameter by thecentimeter range in length. However, AlN dendrites were about 1mm in diameter by 0.5cm in length,and showed an obviously preferential growth orientation, i.e., perpendicular to [21-bar1-bar1] and[101-bar1] planes. It is concluded that the whiskers or dendrites grow via the vapor-solidmechanism.
