2019 journal article

Increasing etching depth of sapphire nanostructures using multilayer etching mask

JOURNAL OF VACUUM SCIENCE & TECHNOLOGY B, 37(6).

By: Y. Chen n, I. Chen n & C. Chang n

co-author countries: United States of America 🇺🇸
Source: Web Of Science
Added: April 14, 2020

In this study, the etching of sapphire nanostructures in inductively coupled plasma reactive ion etching using a multilayer etch mask is studied. The goals are to increase the etching depth and enable the fabrication of higher aspect ratio nanostructures in sapphire, which is traditionally difficult to micromachine. The etching rates and chemistry of different masking materials are examined for better understanding of the etching process. The etching of sapphire nanostructures is then studied using single and multilayer masks with Cl2-based chemistry. The fabrication results show that using the multilayer mask is an effective method for sapphire nanostructure fabrication, increasing the maximum etching depth from 25 to 230 nm for a ninefold improvement. To further validate the optical properties of fabricated sapphire nanostructures, the antireflection effects have been characterized. This work indicates that applying the multilayer mask can increase the etching depth of sapphire nanostructures, which can find applications in thin-film optics, optoelectronic devices, and composite windows.