Comment on 'Sheath model for dual-frequency capacitive discharges'. (8th June 2015)

• Record Type: Journal Article
• Authors: Chen, Wen-Cong; Pu, Yi-Kang
• Is Part Of: Journal of physics. Volume 48:Number 26(2015)
• Publication Date: 2015-06-08
• Subjects: sheath -- dual-frequency -- capacitive discharge; Physics -- Periodicals; 530
• DOI: 10.1088/0022-3727/48/26/268001
• Languages: English
• ISSNs: 0022-3727

Abstract

Abstract: Boyle et al (2004 J. Phys. D: Appl. Phys. 37 1451) introduced a sheath model for dual-frequency capacitive discharges. The electron sheath edge position s and the dc potential Φdc in the sheath are obtained with the assumption α/β >> 1 (where α/β is the ratio of the low-frequency electric field to the high-frequency electric field). However, α/β ≤ 4 is usually found in processing applications. Under this condition, we show that the Boyle et al model gives multiple values for the dc potential Φdc ( x ) at any given position x in the sheath. For this reason, we introduce a model without the assumption α / β >> 1. By comparing the results from the two models, it is found that, as the ratio α / β approaches 1, the sheath thickness s m and the sheath dc voltage V dc obtained with the Boyle et al model are significantly underestimated.