Low-energy ion etching and oxidation of Si in O 2 magnetron plasma

Abstract

Etch and oxidation characteristics of Si surfaces by O 2 magnetron etching were investigated at room temperature using a reactive ion etching (RIE) apparatus with an annular permanent magnet. High etch rates were obtained for Si and SiO 2 at low RF voltages, and were 45 times larger than those obtained in conventional RIE. The etch rate of SiO 2 is always twice as large as that of Si independent of etch conditions. In etching of Si at low RF voltage, the surface was oxidized to a depth of 3.5–6.0 nm, and the oxygen content x in the formed SiO x was confirmed to be 1.5–2.0 from AES and XPS analyses. The metal-oxide-semiconductor (MOS) capacitor measurements showed that the breakdown characteristics of the oxide layers formed at room temperature are excellent, that is, ⩾6 MV/cm.