Fig. 1.
A plot of the groove's step heights and average roughness $R_{\rm a}$ of the wafer's wet-etched area versus oxidation time (line with quadrilateral symbol refers to step height and triangle symbol to $R_{\rm a}$ ).
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| Citation: |
Jinbao Cai, Jinyan Wang, Yang Liu, Zhe Xu, Maojun Wang, Min Yu, Bing Xie, Wengang Wu. A novel oxidation-based wet etching method for AlGaN/GaN heterostructures[J]. Journal of Semiconductors, 2013, 34(8): 086004. doi: 10.1088/1674-4926/34/8/086004
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J B Cai, J Y Wang, Y Liu, Z Xu, M J Wang, M Yu, B Xie, W G Wu. A novel oxidation-based wet etching method for AlGaN/GaN heterostructures[J]. J. Semicond., 2013, 34(8): 086004. doi: 10.1088/1674-4926/34/8/086004.
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A novel oxidation-based wet etching method for AlGaN/GaN heterostructures
DOI: 10.1088/1674-4926/34/8/086004
More Information
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Abstract
A novel wet etching method for AlGaN/GaN heterojunction structures is proposed using thermal oxidation followed by wet etching in KOH solution. It is found that an AlGaN/GaN heterostructure after high temperature oxidation above 700℃ could be etched off in a homothermal (70℃) KOH solution while the KOH solution had no etching effects on the region of the AlGaN/GaN heterostructure protected by a SiO2 layer during the oxidation process. A groove structure with 150 nm step depth on an AlGaN/GaN heterostructure was formed after 8 h thermal oxidation at 900℃ followed by 30 min treatment in 70℃ KOH solution. As the oxidation time increases, the etching depth approaches saturation and the roughness of the etched surface becomes much better. The physical mechanism of this phenomenon is also discussed.-
Keywords:
- AlGaN/GaN,
- wet etching,
- thermal oxidation,
- KOH solution
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References
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