Polarity dependence in Cl2-based plasma etching of GaN, AlGaN and AlN
Polarity dependence in Cl2-based plasma etching of GaN, AlGaN and AlN
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DOI：
10.1016/j.apsusc.2020.146297
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发表时间：
2020-08
影响因子：
6.7
通讯作者：
Matthew D. Smith;Xu Li;M. Uren;I. Thayne;M. Kuball
中科院分区：
文献类型：
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作者：
Matthew D. Smith;Xu Li;M. Uren;I. Thayne;M. Kuball
本研究比较了基于cl2的电感耦合等离子体（ICP）刻蚀n极性和iii极性AlxGa1-xN，包括GaN和AlN。在本研究的蚀刻工艺中，AlxGa1-xN的蚀刻速率随着Al:Ga合金比的增加而降低。在750 W的ICP功率和175 W的压板功率下，AlxGa1-xN的刻蚀速率在160 ~ 450 nm/min之间，具体的刻蚀速率取决于合金成分和材料极性，iii极性材料的AlN和GaN的刻蚀速率选择性为3.0，n极性材料的刻蚀速率选择性为1.6。在650 W ICP功率和50 W压板功率的Cl2/Ar/ o2工艺下，AlxGa1-xN的蚀刻速率在2-360 nm/min范围内整体降低，具体速率取决于合金成分和材料极性。与三极性材料（1.8-1.9）相比，这些含o2的化学物质对n极性材料（8-80）的蚀刻速率选择性显著提高。观察到氮化镓蚀刻速率、表面粗化和选择性之间的相关性，并讨论了蚀刻速率选择性极性依赖的可能原因。
This work compares Cl2-based inductively-coupled plasma (ICP) etching of N-polar and III-polar AlxGa1-xN, including GaN and AlN. For the etch processes of this study, etch rates of AlxGa1-xN decreased with increasing Al:Ga alloy ratio. A 750 W ICP power, 175 W platen power Cl2/Ar ICP process exhibited etch rates in the range 160–450 nm/min for AlxGa1-xN with the precise rate depending on alloy composition and material polarity, and etch rate selectivity between AlN and GaN of 3.0 for III-polar material and 1.6 for N-polar material. Cl2/Ar/O2processes with 650 W ICP power and 50 W platen power showed an overall reduction in etch rate in the range 2–360 nm/min for AlxGa1-xN with precise rate depending on alloy composition and material polarity. These O2containing chemistries demonstrated significantly greater etch rate selectivity for N-polar materials (8–80) compared to III-polar materials (1.8–1.9). A correlation between GaN etch rate, surface roughening and selectivity was observed, and the possible reasons behind the polarity dependence of etch rate selectivity are discussed.