Plasma Enhanced Atomic Layer Deposition of Silicon Nitride for Two Different Aminosilane Precursors Using Very High Frequency (162 MHz) Plasma Source

You Jin Ji; Hae In Kim; Seung Yup Choi; Ji Eun Kang; Albert Rogers Ellingboe; Haripin Chandra; Chang-Won Lee; Geun Young Yeom

doi:10.1021/acsami.3c02950

Plasma Enhanced Atomic Layer Deposition of Silicon Nitride for Two Different Aminosilane Precursors Using Very High Frequency (162 MHz) Plasma Source

ACS Appl Mater Interfaces. 2023 Jun 14;15(23):28763-28771. doi: 10.1021/acsami.3c02950. Epub 2023 Jun 3.

Authors

You Jin Ji¹, Hae In Kim¹, Seung Yup Choi¹, Ji Eun Kang¹, Albert Rogers Ellingboe^{1

2}, Haripin Chandra³, Chang-Won Lee⁴, Geun Young Yeom^{1

5}

Affiliations

¹ School of Advanced Materials Science and Engineering, Sungkyunkwan University, 2066 Seobu-ro, Jangan-gu, Suwon-si, Gyeonggi-do 16419, Republic of Korea.
² Plasma Research Laboratory, School of Physical Sciences and NCPST, Dublin City University, Dublin D9, Ireland.
³ EMD Electronics, 1969 Palomar Oaks Way, Carlsbad, California 92011, United States.
⁴ Merck Korea, Jangjagol-ro 82, Danwon-gu, Ansan-si, Gyeonggi-do 15601, Republic of Korea.
⁵ SKKU Advanced Institute of Nano Technology (SAINT), Sungkyunkwan University, 2066 Seobu-ro, Jangan-gu, Suwon-si, Gyeonggi-do 16419, Republic of Korea.

PMID: 37269552
DOI: 10.1021/acsami.3c02950

Abstract

Plasma enhanced atomic layer deposition (PEALD) of silicon nitride (SiN_x) using very high frequency (VHF, 162 MHz) plasma source was investigated at the process temperatures of 100, 200, and 300 °C. Two aminosilane precursors having different numbers of amino ligands, bis(tert-butylamino)silane (BTBAS) and di(sec-butylamino)silane (DSBAS), were used as Si precursors. A comparative study was also conducted to verify the effect of the number of amino ligands on the properties of SiN_x film. At all process temperatures, DSBAS, having one amino ligand, performed better than BTBAS in various aspects. SiN_x films deposited using DSBAS had lower surface roughness, higher film density, lower wet etch rate, improved electrical characteristics, and higher growth rate than those deposited using BTBAS. With the combination of a VHF plasma source and DSBAS with one amino ligand, the SiN_x films grown at 300 °C exhibited low wet etch rates (≤2 nm/min) in a dilute HF solution (100:1 of deionized water:HF) as well as low C content below the XPS detection limit. Also, excellent step coverage close to 100% on high aspect ratio (30:1) trench structures was obtained by using VHF plasma, which could provide sufficient flux of plasma species inside the trenches in conjunction with DSBAS having fewer amino ligands than BTBAS.

Keywords: BTBAS; DSBAS; N2 plasma; bis(tert-butylamino)silane; conformality; di(sec-butylamino)silane; plasma enhanced atomic layer deposition; silicon nitride.