ICP-RIE etching of MESA and trench SiC structures in SF6 + O2 plasma: significant difference in SiC etching rate dependence on oxygen content

Abstract

Silicon carbide (SiC) is an attractive semiconductor with many excellent properties that can bring huge potential advances in submicron semiconductor processing technology. The inductively coupled plasma reactive ion etching (ICP-RIE) method is widely used in the fabrication technology of various semiconductor devices. The paper presents the results of the ICP-RIE etching of SiC trench or MESA structures. The influence of O₂ addition to the SF₆ plasma on the etching process of these structures is reported. Etched SiC structures are studied by SIMS, SEM, XPS and stylus profilometry. It will be shown that MESA and trench structures have different dependences of the SiC etching rates depending on O₂ content. For trench structures, the initial decrease in the SiC etching rate under increased oxygen content is observed which differs from the trend of MESA dependences obtained in this work, and also reported in the literature. For both types of these structures, the paper presents a possible explanation of the difference in their characteristics of the SiC etching rate on the oxygen content in SF₆ + O₂ gas mixture.