Cracking of GaN films
Cracking of GaN films
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DOI：
10.1063/1.1330243
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发表时间：
2001-01-15
影响因子：
3.2
通讯作者：
Clarke, DR
中科院分区：
文献类型：
--
作者：
Etzkorn, EV;Clarke, DR
蓝宝石上生长的厚GaN膜的开裂的显微结构观察的基础上重新审查的断裂膜和建立力学的组合。有人认为，开裂的动机是拉伸增长应力，一旦达到临界厚度。随后在破裂的膜上发生生长，使破裂的结构永久化，直到裂纹表面彼此接近并接触。薄膜的继续生长掩埋了裂纹。一旦裂纹面接触，就存在能量上有利于裂纹闭合和愈合的条件。裂纹愈合可能受到动力学限制。裂纹愈合是否在生长时间内完成取决于几个因素，包括，它建议，是否有杂质吸附在生长过程中的表面。还提出了在膜生长期间已经延伸到蓝宝石衬底中的裂纹可以作为冷却时衬底断裂的关键缺陷的条件。(C)2001年美国物理学会。
Cracking of thick GaN films grown on sapphire is reexamined on the basis of a combination of microstructural observations of cracking and established mechanics of fracture of films. It is argued that cracking is motivated by tensile growth stresses once a critical thickness is reached. Subsequent growth on the cracked films occurs, perpetuating the cracked structure until the crack surfaces approach one another and touch. Continued film growth buries the crack. Once the crack faces touch, there are conditions under which it is energetically favorable for the cracks to close and heal. Crack healing can be kinetically limited. Whether the crack healing is complete within the growth time depends on several factors including, it is suggested, whether impurities have adsorbed to the surface during growth. Conditions under which cracks that have extended into the sapphire substrate during film growth can act as critical flaws for fracture of the substrate on cooling are also presented. (C) 2001 American Institute of Physics.