title: Atomic Layer Deposition of Wet-Etch Resistant Silicon Nitride Using Di(sec-butylamino)silane and N2Plasma on Planar and 3D Substrate Topographies.
abstract: The advent of three-dimensional (3D) finFET transistors and emergence of novel memory technologies place stringent requirements on the processing of silicon nitride (SiNx) films used for a variety of applications in device manufacturing. In many cases, a low temperature (<400 °C) deposition process is desired that yields high quality SiNxfilms that are etch resistant and also conformal when grown on 3D substrate topographies. In this work, we developed a novel plasma-enhanced atomic layer deposition (PEALD) process for SiNxusing a mono-aminosilane precursor, di(sec-butylamino)silane (DSBAS, SiH3N(sBu)2), and N2plasma. Material properties have been analyzed over a wide stage temperature range (100-500 °C) and compared with those obtained in our previous work for SiNxdeposited using a bis-aminosilane precursor, bis(tert-butylamino)silane (BTBAS, SiH2(NHtBu)2), and N2plasma. Dense films (∼3.1 g/cm3) with low C, O, and H contents at low substrate temperatures (<400 °C) were obtained on planar substrates for this process when compared to other processes reported in the literature. The developed process was also used for depositing SiNxfilms on high aspect ratio (4.5:1) 3D trench nanostructures to investigate film conformality and wet-etch resistance (in dilute hydrofluoric acid, HF/H2O = 1:100) relevant for state-of-the-art device architectures. Film conformality was below the desired levels of >95% and attributed to the combined role played by nitrogen plasma soft saturation, radical species recombination, and ion directionality during SiNxdeposition on 3D substrates. Yet, very low wet-etch rates (WER ≤ 2 nm/min) were observed at the top, sidewall, and bottom trench regions of the most conformal film deposited at low substrate temperature (<400 °C), which confirmed that the process is applicable for depositing high quality SiNxfilms on both planar and 3D substrate topographies.
authors.affiliation: Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands.
authors.forename: Tahsin
authors.identifier: http://orcid.org/0000-0001-8497-861X
authors.initials: T
authors.lastname: Faraz
authors.affiliation: Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands.
authors.forename: Maarten
authors.initials: M
authors.lastname: van Drunen
authors.affiliation: Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands.|Oxford Instruments Plasma Technology, North End, Bristol BS49 4AP, U.K.
authors.forename: Harm C M
authors.identifier: http://orcid.org/0000-0003-2284-4477
authors.initials: HC
authors.lastname: Knoops
authors.affiliation: Air Products and Chemicals Inc., 1969 Palomar Oaks Way, Carlsbad, California 92011, United States.
authors.forename: Anupama
authors.initials: A
authors.lastname: Mallikarjunan
authors.affiliation: Air Products and Chemicals Inc., 1969 Palomar Oaks Way, Carlsbad, California 92011, United States.
authors.forename: Iain
authors.initials: I
authors.lastname: Buchanan
authors.affiliation: Lam Research Corporation, 11155 Southwest Leveton Drive, Tualatin, Oregon 97062, United States.
authors.forename: Dennis M
authors.initials: DM
authors.lastname: Hausmann
authors.affiliation: Lam Research Corporation, 11155 Southwest Leveton Drive, Tualatin, Oregon 97062, United States.
authors.forename: Jon
authors.initials: J
authors.lastname: Henri
authors.affiliation: Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands.
authors.forename: Wilhelmus M M
authors.initials: WM
authors.lastname: Kessels
keywords: ALD; DSBAS; atomic layer deposition; di(sec-butylamino)silane; plasma ALD; silicon nitride; thin film; wet etch