Optimizing the Isotropic Etching Nature and Etch Profile of Si, Ge and Si0.8Ge0.2 by Controlling CF4 Atmosphere With Ar and O2 Additives in ICP

Ashish Kumar, Wen-Hsi Lee, Y. L. Wang

2021IEEE Transactions on Semiconductor Manufacturing15 citationsDOI Open Access PDF

Abstract

An isotropic etching, etch rate and surface roughness of Si, Ge and Si 0.8 Ge 0.2 subjected to CF 4 /Ar/O 2 plasma has been studied using inductively coupled plasma (ICP) system. First, we applied the etching parameters on the silicon substrate to observe the etching rate using carbon tetrafluoride (CF 4 ) under different flow rates and choose the parameters of high etch rate. The chosen parameters for silicon was CF 4 (60 sccm) and etching in different ratios of argon (Ar) and oxygen (O 2 ) were also discussed. Second, it also reports on selective isotropic etching for germanium (Ge) and Si 0.8 Ge 0.2 by ultrahigh vacuum chemical vapor deposition (UHVCVD) and was etched under selected conditions used for silicon under different atmospheres in an inductively coupled plasma system. Starting from a pure CF 4 gas that etches Ge and Si 0.8 Ge 0.2 with a good selectivity to silicon, the modification of gas mixture was also investigated. A possible mechanism based on the favored action of CF 4 is investigated. Relative etch rate between Si, Ge and Si 0.8 Ge 0.2 are explained with etch rate reductions achieved by selective CF 4 plasma chemistries with Ar/O 2 . Etched profile, surface roughness was examined and measured by using SEM and AFM technique.

Topics & Concepts

Etching (microfabrication)Analytical Chemistry (journal)Materials scienceNanotechnologyChemistryOrganic chemistryLayer (electronics)Semiconductor materials and devicesPlasma Diagnostics and ApplicationsAdvancements in Semiconductor Devices and Circuit Design

Optimizing the Isotropic Etching Nature and Etch Profile of Si, Ge and Si<sub>0.8</sub>Ge<sub>0.2</sub> by Controlling CF<sub>4</sub> Atmosphere With Ar and O<sub>2</sub> Additives in ICP

Abstract

Topics & Concepts