(Invited) Thermal Cyclic Atomic-Level Etching of Nitride Films: A Novel Way for Atomic-Scale Nanofabrication. (14th August 2017)

• Record Type: Journal Article
• Authors: Shinoda, Kazunori; Miyoshi, Nobuya; Kobayashi, Hiroyuki; Kurihara, Masaru; Izawa, Masaru; Ishikawa, Kenji; Hori, Masaru
• Is Part Of: ECS transactions. Volume 80:Number 3(2017)
• Page Start: 3
• Page End: 14
• Publication Date: 2017-08-14
• Subjects: Electrochemistry -- Periodicals; Electrochemistry; Periodicals; Electronic journals; Electronic journal; 541.37
• DOI: 10.1149/08003.0003ecst
• Languages: English
• ISSNs: 1938-5862

Abstract

Abstract : A highly selective, rapid thermal-cyclic atomic-level etching (ALE) process for SiNx film has been developed. The first step of this process is exposing SiNx to hydrofluorocarbon plasma to form an (NH4 )2 SiF6 layer on the SiNx surface. The second step is rapid thermal annealing with an infrared (IR) irradiation to decompose and sublimate the (NH4 )2 SiF6 layer. Etching of SiNx was observed after the (NH4 )2 SiF6 layer was removed by thermal annealing. Cyclic etching tests were carried out by repeated plasma exposure and IR irradiation. It was found that the cyclic process is self-limiting because etching depth depends only on the cycle number and not on the plasma exposure time. A high selectivity over SiO2 and poly Si was confirmed. This paper reviews the novel isotropic ALE for nitride films focusing on the surface reaction mechanism investigated by x-ray photoelectron spectroscopy (XPS) and thermal desorption spectroscopy (TDS). Isotropic ALE of TiN was also demonstrated using the same approach.