Dry etching characteristics of GaN using Cl2/BCl3 inductively coupled plasmas
Dry etching characteristics of GaN using Cl2/BCl3 inductively coupled plasmas
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DOI：
10.1016/j.apsusc.2010.07.088
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发表时间：
2010-11-15
影响因子：
6.7
通讯作者：
Liu, Sheng
中科院分区：
文献类型：
--
作者：
Zhou, Shengjun;Cao, Bin;Liu, Sheng
改变 ICP 功率/射频功率、工作压力和 Cl-2/BCl3 气体混合比，以研究输入工艺参数对 GaN 薄膜蚀刻特性的影响。研究了 GaN 相对于 SiO2 和光刻胶的刻蚀选择性。虽然较高的ICP/RF功率可以获得较高的GaN/光刻胶蚀刻选择性，但由于光刻胶掩模腐蚀，它可能导致侧壁刻面和奇怪的侧壁轮廓。在固定ICP/RF功率和混合成分下，GaN和SiO2的刻蚀速率随着操作压力的增加而降低，并且GaN相对于SiO2的刻蚀选择性随着操作压力的增加而增加。 GaN相对于SiO2的最高蚀刻选择性为7.92，并且可以实现GaN蚀刻速率接近845.3 nm/min的几乎垂直的蚀刻轮廓。通过原子力显微镜评估了不同刻蚀条件下刻蚀的 GaN 的表面形貌和均方根粗糙度。使用光致发光 (PL) 测量来分析等离子体引起的 GaN 损伤。介绍了用于 LED 制造过程中台面形成的优化蚀刻工艺。使用 Cl-2/BCl3 等离子体化学和硬掩模 SiO2 的组合可以将周期性图案转移到 GaN 中。使用相同的等离子体化学物质也可以对蓝宝石衬底进行图案化，以制造具有更高提取效率的 LED。 (C) 2010 Elsevier B.V. 保留所有权利。
ICP power/RF power, operating pressure, and Cl-2/BCl3 gas mixing ratio are altered to investigate the effect of input process parameters on the etch characteristics of GaN films. The etch selectivity of GaN over SiO2 and photoresist is studied. Although higher ICP/RF power can obtain higher GaN/photoresist etch selectivity, it can result in faceting of sidewall and weird sidewall profile due to photoresist mask erosion. Etch rates of GaN and SiO2 decrease with the increase of operating pressure, and etch selectivity of GaN over SiO2 increases with the increasing operating pressure at fixed ICP/RF power and mixture component. The highest etch selectivity of GaN over SiO2 is 7.92, and an almost vertical etch profile having an etch rate of GaN close to 845.3 nm/min can be achieved. The surface morphology and root-mean-square roughness of the etched GaN under different etching conditions are evaluated by atomic force microscopy. The plasma-induced damage of GaN is analyzed using photoluminescence (PL) measurements. The optimized etching process, used for mesa formation during the LED fabrication, is presented. The periodic pattern can be transferred into GaN using a combination of Cl-2/BCl3 plasma chemistry and hard mask SiO2. Patterning of the sapphire substrate for fabricating LED with improved extraction efficiency is also possible using the same plasma chemistry. (C) 2010 Elsevier B.V. All rights reserved.