Nanowall formation by maskless wet-etching on a femtosecond laser irradiated silicon surface

• Published in: Applied surface science 2018-04, Vol.437, p.190-194
• Main Authors: Lee, Siwoo, Jo, Kukhyun, Keum, Hee-sung, Chae, Sangmin, Kim, Yonghyeon, Choi, Jiyeon, Lee, Hyun Hwi, Kim, Hyo Jung
• Format: Article
• Language: English
• Subjects: LIPSS; Maskless patterning; Microcell; Nanowall; Wet-etching
• ISSN: 0169-4332; 1873-5584
• DOI: 10.1016/j.apsusc.2017.12.155

[Display omitted] •High aspect ratio nanowalls with micro-cells were fabricated by laser assisted wet-etching process.•The surface roughness of micro-cells was 3.10 nm on average.•Nanowalls improved the lateral growth of thin film phase penetacene layer by size confining effect. We found that micro-cells surrounded by nanowalls can be formed by a maskless wet-etching process on Si (100) surfaces possessing Laser Induced Periodic Surface Structure (LIPSS) by femtosecond laser irradiation. The LIPSS process could produce periodic one-dimensional micron scale ripples on a Si surface, which could be developed into micro-cells by a subsequent etching process. The solution etching conditions strongly affected both the micro-cell and nanowall shapes such as the height and the thickness of nanowalls. The tetramethylammonium hydroxide solution created thin nanowalls and the resulting micro-cells with a well-flattened bottom while the KOH solution formed thick walls and incomplete micro-cells. The bottoms of micro-cells surrounded by the nanowalls were considerably flat with a 3.10 nm surface roughness. A pentacene layer was deposited on the micro-cells of a Si surface to evaluate the film properties by grazing incidence wide angle x-ray scattering measurements. The pentacene film on the micro-cell Si surface showed a strong film phase, which was comparable to the film phase grown on the atomically flat Si surface.