Low stacking-fault density in ZnSe epilayers directly grown on epi-ready GaAs substrates without GaAs buffer layers
Low stacking-fault density in ZnSe epilayers directly grown on epi-ready GaAs substrates without GaAs buffer layers
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DOI：
10.1063/1.1339262
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发表时间：
2001-01
影响因子：
4
通讯作者：
Soon-Ku Hong;E. Kurtz;J. Chang;T. Hanada;M. Oku;T. Yao
中科院分区：
文献类型：
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作者：
Soon-Ku Hong;E. Kurtz;J. Chang;T. Hanada;M. Oku;T. Yao
我们报告了直接在商用外延就绪 GaAs (001) 衬底上生长的 ZnSe 外延层中的堆垛层错密度非常低，而无需生长 GaAs 缓冲层。研究发现，对外延就绪的 GaAs (001) 衬底进行适当的预生长处理以获得清洁的表面对于二维逐层生长和抑制堆垛层错的产生至关重要。发现使用NH4OH基溶液的化学蚀刻不仅可以减少氧化物层的厚度，而且可以将Ga2O3与As2O3的比率减少到蚀刻前的大约一半。在热清洗和锌预曝光之后，获得了在本例中以（4×1）重构为特征的干净的GaAs（001）表面。即使从在如此清洁的 GaAs 衬底上生长 ZnSe 的一开始，也可以观察到超过 50 个周期的反射高能电子衍射强度振荡。这种 ZnSe 层中的堆垛层错密度在 105 cm−2 范围内。
We report a remarkably low stacking-fault density in ZnSe epilayers directly grown on commercial epi-ready GaAs (001) substrates without GaAs buffer layer growth. It is found that proper pregrowth treatments on epi-ready GaAs (001) substrates to obtain clean surfaces are crucial for two-dimensional layer-by-layer growth and suppression of stacking fault generation. Chemical etching using a NH4OH-based solution is found to reduce not only the thickness of the oxide layers but also the ratio of Ga2O3 to As2O3 to about half of that before etching. A clean GaAs (001) surface characterized by a (4×1) reconstruction in the present case is obtained after thermal cleaning followed by Zn pre-exposure. Reflection high-energy electron diffraction intensity oscillations with more than 50 periods are observed even from the very beginning of ZnSe growth on GaAs substrates cleaned as such. The stacking fault density in such a ZnSe layer is in the low-105 cm−2 range.