Reflectance anisotropy spectroscopy (RAS) for III/V semiconductor crystal dry-etching (RIE) for in-situ identification of self-organized roughness (roughness-RIE-RAS)
Final Report Abstract
In semiconductor technology, a common process is the etching of wafers at their surface. For this purpose, so-called dry etching in a plasma is often used, e.g., reactive ion etching (RIE). The better a RIE process can be controlled and corrected during its course, the higher the yield of samples or components will be, which makes the process faster and more cost-effective. This is advantageous both for research as well as for industrial applications. Reflectivity anisotropy spectroscopy (RAS) is an optical technique that allows crystalline surfaces to be monitored with high accuracy, even in real time, i.e., while the wafers or samples are being treated in a vacuum chamber. Originally, RAS had been developed to monitor crystal growth. The working group has also applied the method to RIE. In the project reported here, the focus has specifically been on using RAS to detect surface roughness that can occur during etching. This could be an undesirable roughness that can be eliminated by rapid readjustment of the etching parameters. Or it could be a desired roughness that is supposed to serves as a functional layer on the sample, e.g., as an anti-reflective layer. In this project, it has been shown that RAS can be used to detect and distinguish between roughness morphologies even during RIE processes - with the aid of complex statistical methods. Even within a specific roughness morphology class, differences between samples can be clearly identified. Thus, the RIE-RAS combination is even more successful than expected and hoped for at the beginning of the project.
Publications
-
Reactive Ion Etching (RIE) Induced Surface Roughness Precisely Monitored In-Situ and in Real Time by Reflectance Anisotropy Spectroscopy (RAS) in Combination with Principle Component Analysis (PCA). Advances in Materials Science and Engineering, 2022 (2022, 11, 11), 1-7.
Oliveira, Emerson; Strassner, Johannes; Doering, Christoph & Fouckhardt, Henning
-
Reflectance anisotropy spectroscopy (RAS) for in-situ identification of roughness morphologies evolving during reactive ion etching (RIE). Applied Surface Science, 611, 155769.
Oliveira, Emerson; Strassner, Johannes; Doering, Christoph & Fouckhardt, Henning
