Heteroepitaxial growth of GaN on sapphire substrates by high temperature vapor phase epitaxy
Heteroepitaxial growth of GaN on sapphire substrates by high temperature vapor phase epitaxy
复制标题
DOI：
10.1016/j.jcrysgro.2019.125185
复制
发表时间：
2019-10-15
影响因子：
1.8
通讯作者：
Stelter, M.
中科院分区：
文献类型：
--
作者：
Lukin, G.;Schneider, T.;Stelter, M.
本文介绍了在蓝宝石衬底上直接沉积GaN层的高温气相外延（HTVPE）技术的最新进展以及改进的沉积技术对HTVPE GaN层质量的影响。该技术使用改进的HTVPE反应器以更好地控制生长过程。该反应器包含一个新设计的Ga蒸发单元，由难熔金属制成，可显著降低工艺诱导杂质的浓度。结果，HTVPE层中的杂质浓度降低到或低于10（16）cm（-3）。为了在（0001）取向的蓝宝石上直接沉积GaN，开发了包括成核层和籽晶层的生长的多步骤工艺，所述籽晶层可以用作模板，用于以增加的生长速率进一步过度生长以产生几十μ m厚的GaN层。的HTVPE层的性质，其特征在于通过光学和扫描电子显微镜，辉光放电质谱，拉曼光谱，X射线衍射，和光致发光。的残余应力和位错密度的种子和过度生长层，并通过建立的化学气相外延方法生长的层的属性进行比较。在此背景下，HTVPE方法的挑战和前景进行了讨论。
This paper presents recent progress in the development of the high temperature vapor phase epitaxy (HTVPE) for a direct deposition of GaN layers on sapphire substrates and the impact of the improved deposition technique on the quality of the HTVPE GaN layers. This technique uses an improved HTVPE reactor for a better control of the growth process. The reactor contains a newly designed Ga evaporation cell made of refractory metals, which significantly reduces the concentration of process-induced impurities. As a result, the impurity concentrations in the HTVPE layers were reduced to or below 10(16) cm(-3). For a direct deposition of GaN on (0001)-oriented sapphire, a multi-step process was developed that includes the growth of a nucleation layer and a seed layer, which can be used as a template for further overgrowth with an increased growth rate to produce several ten mu m thick GaN layers. The properties of the HTVPE layers are characterized by optical and scanning electron microscopy, glow discharge mass spectrometry, Raman spectroscopy, X-ray diffraction, and photoluminescence. The residual stresses and dislocation densities are presented for seed and overgrown layers, and compared with the properties of layers grown by established methods of chemical vapor phase epitaxy. In this context, challenges and prospects of the HTVPE method are discussed.