[22p-A406-1~15] 8.2 Plasma deposition of thin film, plasma etching and surface treatment

[22p-A406-4] Self-limiting cyclic etching of SiGe by using plasma-assisted thermal-cyclic method

〇Kazunori Shinoda¹, Katsuya Miura¹, Kenji Maeda², Masaru Izawa², Thi-Thuy-Nga Nguyen³, Kenji Ishikawa³, Masaru Hori³ (1.Hitachi R&D, 2.Hitachi High-Tech, 3.Nagoya Univ.)

Keywords:etching, plasma, silicon germanium

Plasma-assisted thermal-cyclic etching of SiGe was demonstrated. The experimental apparatus composed of a reaction chamber and an x-ray photoelectron spectroscopy. Samples were exposed to radicals that were generated in plasmas of hydrofluorocarbon-based gas mixtures that were added with nitrogen. A nitrogen 1s peak, which was likely ascribed to N-H bond, was observed after plasma exposure. This result could imply that ammonium salt-based modified layer forms on the surface after plasma exposure. The nitrogen 1s peak disappeared when the sample was heated at 100℃. Cyclic etching was carried out by repeating plasma exposure and infrared heating using 300-mm apparatus. The etching depth of SiGe increased with increasing the number of cycles. The etching depth of SiGe showed saturation behavior with respect to plasma-exposure time. The etching depth of Ge was smaller than that of SiGe.