Study on sapphire surface preparation for III-nitride heteroepitaxial growth by chemical treatments
Study on sapphire surface preparation for III-nitride heteroepitaxial growth by chemical treatments
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DOI：
10.1149/1.1509072
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发表时间：
2002-11-01
影响因子：
3.9
通讯作者：
Kuech, TF
中科院分区：
文献类型：
--
作者：
Dwikusuma, F;Saulys, D;Kuech, TF
利用原子力显微镜系统地研究了使用H2SO 4、H3 PO 4和3：1的H2SO 4：H3 PO 4混合物作为温度和蚀刻时间的函数的蓝宝石衬底的蚀刻。比较了液基腐蚀法制备蓝宝石与1100 ℃ H-2腐蚀法和1400 ℃空气退火法制备蓝宝石。在液基处理中，通过在300 ℃的纯H2SO 4中蚀刻30分钟获得最光滑、无坑的表面。在更高温度或更长时间的硫酸蚀刻在表面上产生Al-2（SO 4）（3）和Al-2（SO 4）（3）.17H（2）O晶体沉积物的不溶性混合物。磷酸和3：1 H2SO 4：H3 PO 4混合物（这是蓝宝石制备中常规使用的化学处理）优先在缺陷部位蚀刻蓝宝石，并导致表面上形成凹坑。在1100 ℃下使用H-2的蓝宝石处理不能去除表面损伤。在1400 ℃下空气退火蓝宝石1小时，产生由台阶和台阶结构组成的原子级光滑表面。这项研究的结果进行了描述的蓝宝石蚀刻工艺的化学。(C)2002年电化学学会。
The etching of sapphire substrates using H2SO4, H3PO4, and a 3:1 H2SO4 :H3PO4 mixture, as a function of temperature and etching time, was systematically studied using atomic force microscopy. The sapphire preparation by liquid-based etchings was compared with H-2 etching at 1100degreesC and air-annealing at 1400degreesC. In liquid-based treatments, the smoothest, pit-free surface was obtained by etching in pure H2SO4 at 300degreesC for 30 min. Sulfuric acid etching at higher temperatures or for longer periods generated an insoluble mixture of Al-2(SO4)(3) and Al-2(SO4)(3).17H(2)O crystalline deposits on the surface. Phosphoric acid and the 3:1 H2SO4:H3PO4 mixture, which is the routinely employed chemical treatment for sapphire preparation, etched the sapphire preferentially at defect sites and resulted in pit formation on the surface. Sapphire treatment using H-2 at 1100degreesC did not remove the surface damage. Air annealing the sapphire at 1400degreesC for 1 h produced an atomically smooth surface consisting of a terrace-and-step structure. The results of this study were described in terms of the chemistry of the sapphire etching process. (C) 2002 The Electrochemical Society.