This paper reports an experimental investigation of Cl2 versus HBr for plasma atomic layer etching of silicon. An inductively coupled plasma (ICP) source with a constant flow of Ar carrier gases and HBr or Cl2 as a dosing gas was used for etching Si (100). Two modes of dosing were investigated: plasma gas dosing, in which pulsed flows of Cl2 or HBr are partially dissociated with the ICP with no substrate bias, and gas dosing, where the ICP is off during the dosing step. Following either dosing mode, a purge step of up to 5 s is followed by a 1 s period of ICP and substrate bias power, leading to etching of the halogenated surface layer. Optical emission spectroscopy was used to follow relative yields of SiCl, SiCl2, and SiBr, and scanning electron microscopy and profilometry were used to measure etching rates. Plasma gas dosing resulted in etching rates three to four times higher than gas dosing. Small differences were found between the two etchant feed gases, with Cl2 exhibiting about 3%–15% higher etching rate. Etched profiles for HBr plasma gas dosing produced little or no microtrench adjacent to the SiO2-masked line, while HBr gas dosing or Cl2 with either mode of dosing produced microtrenches at the bottom of the Si sidewall.
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January 2025
Research Article|
December 06 2024
Comparisons of atomic layer etching of silicon in Cl2 and HBr-containing plasmas
Special Collection:
Atomic Layer Etching (ALE)
Mahmoud A. I. Elgarhy
;
Mahmoud A. I. Elgarhy
(Data curation, Formal analysis, Writing – original draft, Writing – review & editing)
1
William A. Brookshire Department of Chemical and Biomolecular Engineering, University of Houston
, Houston, Texas 772042
Physics Department, Faculty of Science, Al-Azhar University
, Cairo 11651, Egypt
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Qinzhen Hao
;
Qinzhen Hao
(Data curation, Formal analysis, Writing – original draft, Writing – review & editing)
1
William A. Brookshire Department of Chemical and Biomolecular Engineering, University of Houston
, Houston, Texas 77204
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Heejung Kim;
Heejung Kim
(Conceptualization, Funding acquisition)
3
Semiconductor R&D Center, Samsung Electronics Co., Ltd.
, Hwaseong-si, Gyeonggi-do 18448, South Korea
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Sang Ki Nam
;
Sang Ki Nam
(Conceptualization, Funding acquisition, Resources)
4
Mechatronics Research, Samsung Electronics Co., Ltd.
, Hwaseong-si, Gyeonggi-do 18448, South Korea
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Song-Yun Kang
;
Song-Yun Kang
(Conceptualization, Funding acquisition, Resources)
3
Semiconductor R&D Center, Samsung Electronics Co., Ltd.
, Hwaseong-si, Gyeonggi-do 18448, South Korea
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Vincent M. Donnelly
Vincent M. Donnelly
a)
(Conceptualization, Formal analysis, Funding acquisition, Project administration, Writing – original draft, Writing – review & editing)
1
William A. Brookshire Department of Chemical and Biomolecular Engineering, University of Houston
, Houston, Texas 77204
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a)
Electronic mail: [email protected]
J. Vac. Sci. Technol. A 43, 012601 (2025)
Article history
Received:
September 19 2024
Accepted:
November 08 2024
Citation
Mahmoud A. I. Elgarhy, Qinzhen Hao, Heejung Kim, Sang Ki Nam, Song-Yun Kang, Vincent M. Donnelly; Comparisons of atomic layer etching of silicon in Cl2 and HBr-containing plasmas. J. Vac. Sci. Technol. A 1 January 2025; 43 (1): 012601. https://doi.org/10.1116/6.0004092
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