Fabrication of crystalline silicon nanowire arrays using deep reactive ion etching process

Abstract

Nanostructures have fascinating physical properties that the bulk material doesn’t exhibit. Especially, the optical and electrical properties of silicon nanowires (SiNWs) have attracted much attention for application in various devices such as solar cells and photodetectors. These characteristics can be systematically controlled by changing their physical dimensions (e.g., diameter and length). Consequently, it is the key to controlling the size of nanowires precisely to realize desired properties. This study demonstrates how to fabricate vertical nanowire arrays using electron beam lithography (EBL) and deep reactive ion etching (DRIE) process. The DRIE process, as one of the dry etching processes, is a highly anisotropic etching process. By providing high ion current density, it enables to etch silicon with fast etching rates and to produce nanostructures with a high aspect ratio compared to other dry etching processes. Therefore, it is a very suitable method for vertical SiNW arrays fabrication. Furthermore, this study focuses on the morphological changes of the SiNW arrays with various pitches and diameters by controlling temperature and the flow rate of SF6 and C4F8 gases during the DRIE process.