High-density plasma etching of indium–zinc oxide films in Ar/Cl 2 and Ar/CH 4/H 2 chemistries

• Published in: Applied surface science Vol. 253; no. 5; pp. 2752 - 2757
• Main Authors: Lim, W.T., Stafford, L., Song, Ju-Il, Park, Jae-Soung, Heo, Y.W., Lee, Joon-Hyung, Kim, Jeong-Joo, Pearton, S.J.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 30.12.2006
• Subjects: Dry etching; Indium–zinc oxide; Dry etching; Indium–zinc oxide
• ISSN: 0169-4332; 1873-5584
• DOI: 10.1016/j.apsusc.2006.05.052

The dry etching characteristics of transparent and conductive indium–zinc oxide (IZO) films have been investigated using an inductively coupled high-density plasma. While the Cl 2-based plasma mixture showed little enhancement over physical sputtering in a pure argon atmosphere, the CH 4/H 2/Ar chemistry produced an increase of the IZO etch rate. On the other hand, the surface morphology of IZO films after etching in Ar and Ar/Cl 2 discharges is smooth, whereas that after etching in CH 4/H 2/Ar presents particle-like features resulting from the preferential desorption of In- and O-containing products. Etching in CH 4/H 2/Ar also produces formation of a Zn-rich surface layer, whose thickness (∼40 nm) is well-above the expected range of incident ions in the material (∼1 nm). Such alteration of the IZO layer after etching in CH 4/H 2/Ar plasmas is expected to have a significant impact on the transparent electrode properties in optoelectronic device fabrication.