Precipitates originating from tungsten crucible parts in AlN bulk crystals grown by the PVT method
Precipitates originating from tungsten crucible parts in AlN bulk crystals grown by the PVT method
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源自 PVT 方法生长的 AlN 块状晶体中钨坩埚部件的沉淀物
DOI：
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发表时间：
2016
期刊：
影响因子：
--
通讯作者：
M. Bickermann
中科院分区：
文献类型：
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作者：
F. Langhans;S. Kiefer;C. Hartmann;T. Markurt;T. Schulz;C. Guguschev;Martin Naumann;S. Kollowa;A. Dittmar;J. Wollweber;M. Bickermann
为了评估坩埚材料在通过物理气相输送生长的AlN块状晶体生长中的可能参与，我们应用了具有高垂直热梯度和高铝蒸气过饱和的生长条件。在这些条件下，沉淀形成，在初始生长界面和晶体中形成弥漫性灰色亚结构，装饰位错。电镜研究表明，析出相是细长的单相颗粒，尺寸为50-500 nm，结构相当，取向于< 11.2¯0>方向。沉淀物的化学分析显示钨、碳和氧。析出相的晶格参数与六方半碳化钨（W2C）基本一致。讨论了钨组分的输运及其转化为碳化钨析出物的可能性。因此，我们得出结论，W2C沉淀可能有助于位错的装饰，即使在中等热梯度的生长中也是如此。
In order to evaluate the possible involvement of crucible materials in the growth of AlN bulk crystals grown by physical vapor transport, we applied growth conditions with a high vertical thermal gradient and hence high supersaturation of aluminum vapor. Under these conditions, precipitates formed causing diffuse grayish substructures at the initial growth interface and in the crystal body, decorating dislocations. Electron microscopy studies revealed that the precipitates are elongated, single‐phase particles with sizes of 50–500 nm of commensurate structure, oriented along the <11 2¯ 0> direction. Chemical analysis of the precipitates showed tungsten as well as carbon and oxygen. The lattice parameters of the precipitates are in close agreement to hexagonal tungsten hemicarbide (W2C). The possible transport from the tungsten parts and its conversion into tungsten hemicarbide precipitates is discussed. We thus conclude that the W2C precipitates may contribute to the decoration of dislocations, even in growth with moderate thermal gradients.
影响因子：
1.5
作者：
Hartmann, Carsten;Wollweber, Juergen;Bickermann, Matthias
通讯作者：
Bickermann, Matthias