Cubic GaN formation in Mn/GaN multilayer films grown on 6H-SiC(0001)
Cubic GaN formation in Mn/GaN multilayer films grown on 6H-SiC(0001)
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6H-SiC 上生长的 Mn/GaN 多层薄膜中立方 GaN 的形成（0001）
DOI：
10.1063/1.1586455
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发表时间：
2003
影响因子：
4
通讯作者：
Lian Li
中科院分区：
文献类型：
--
作者：
Y. Cui;V. K. Lazorov;M. Goetz;H. Liu;D. Robertson;M. Gajdardziska;Lian Li
采用电子回旋共振等离子体辅助分子束外延技术在6H-SiC（0001）衬底上生长了立方相GaN。生长过程包括首先沉积20-nm GaN缓冲层，然后是10个周期的1个单层（ML）Mn和10 ML GaN的交替层，最后用30 nm GaN覆盖。记录薄膜横截面的高分辨率透射电子显微照片，并计算数字衍射图以确定不同薄膜层的晶格结构。发现GaN缓冲和覆盖层中的晶体结构与2H-纤锌矿GaN匹配。然而，观察到均匀的立方锌掺杂GaN相代替标称多层Mn/GaN区域。通常在GaN膜中观察到的缺陷密度在立方层和覆盖层内急剧降低，表明可能由于Mn的表面活性剂效应而改善的膜质量。基于一维伊辛多型体形成模型，提出了一种机制来解释立方GaN的生长。
Cubic GaN was grown on 6H-SiC(0001) by electron-cyclotron resonance plasma-assisted molecular-beam epitaxy. The growth process consisted of first depositing a 20-nm GaN buffer, followed by ten periods of alternating layers of 1 monolayer (ML) Mn and 10 ML GaN, and finally capped with 30 nm GaN. High-resolution transmission electron micrographs of film cross sections were recorded and digital diffractograms were calculated to determine the lattice structures of the different film layers. It was found that the crystal structure in the GaN buffer and capping layer matches the 2H-wurtzite GaN. However, uniform cubic zinc-blende GaN phase was observed in place of the nominal multilayer Mn/GaN region. The density of defects typically observed in GaN films is drastically reduced within the cubic and capping layer, indicating improved film quality possibly due to the surfactant effect of Mn. Based on the one-dimensional Ising model of polytype formation, a mechanism is proposed to explain the growth of cubic GaN ...