Showing papers by "Yihwan Kim published in 2016"
TL;DR: In this article, a two-stage, highly selective CF4 plasma dry etch and HCl wet etch was used to achieve consistent etch control as low as 1.5nm per cycle.
Abstract: The development of a precise micromachining process for Ge1–xSnx has the potential to enable both the fabrication and optimization of Ge1−xSnx-based devices in photonics and microelectromechanical systems. We demonstrate a digital etching scheme for Ge0.922Sn0.078 based on a two-stage, highly selective CF4 plasma dry etch and HCl wet etch. Using X-Ray Reflectivity, we show consistent etch control as low as 1.5 nm per cycle, which is defined as one dry etch step followed by one wet etch step. The etch rate increases to 3.2 nm per cycle for a longer dry etch time due to physical sputtering contributions, accompanied by an increase in RMS surface roughness. By operating within a regime with minimal sputtering, we demonstrate that good digital etch depth control and surface quality can be achieved using this technique.
15 citations