Surface reactions of aminosilane precursors during N2 plasma‐assisted atomic layer deposition of SiNx

Leick, Noémi; Huijs, Jochem M.M.; Ovanesyan, Rafaiel A.; Hausmann, Dennis M.; Agarwal, Sumit

doi:10.1002/ppap.201900032

Cited by 12 publications

(8 citation statements)

References 55 publications

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“…This could be due to the anisotropic nature of N 2 + ion bombardment, which preferentially improves film properties at horizontal surfaces more than those at vertical ones. The trade-off between high conformality and high quality (i.e., low WERs, high density) observed for SiN x films deposited on 3D substrate topography in this work seems to be a generally observed phenomenon for ALD processes of SiN x . , Processes employing chlorosilane precursors and NH 3 gas or NH 3 plasma report films having high conformality but low film quality (i.e., high WERs, low density), ,, whereas those using an organosilane precursor and N 2 plasma report films with the properties reversed. , The latter is consistent with the results obtained in this work.…”

Section: Discussionmentioning

confidence: 54%

Atomic Layer Deposition of Wet-Etch Resistant Silicon Nitride Using Di(sec-butylamino)silane and N₂Plasma on Planar and 3D Substrate Topographies

Faraz

Drunen

Knoops

et al. 2017

ACS Appl. Mater. Interfaces

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The advent of three-dimensional (3D) finFET transistors and emergence of novel memory technologies place stringent requirements on the processing of silicon nitride (SiN) 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 SiN films 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 SiN using a mono-aminosilane precursor, di(sec-butylamino)silane (DSBAS, SiHN(Bu)), and N plasma. Material properties have been analyzed over a wide stage temperature range (100-500 °C) and compared with those obtained in our previous work for SiN deposited using a bis-aminosilane precursor, bis(tert-butylamino)silane (BTBAS, SiH(NHBu)), and N plasma. Dense films (∼3.1 g/cm) 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 SiN films on high aspect ratio (4.5:1) 3D trench nanostructures to investigate film conformality and wet-etch resistance (in dilute hydrofluoric acid, HF/HO = 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 SiN deposition 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 SiN films on both planar and 3D substrate topographies.

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Section: Discussionmentioning

confidence: 54%

Atomic Layer Deposition of Wet-Etch Resistant Silicon Nitride Using Di(sec-butylamino)silane and N₂Plasma on Planar and 3D Substrate Topographies

Faraz

Drunen

Knoops

et al. 2017

ACS Appl. Mater. Interfaces

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“…Furthermore, as one of the first aminosilanes that had been explored, 45 BDEAS has been employed in several ALD processes: for SiO 2 using both O 3 and O 2 plasma, for Si 3 N 4 using N 2 plasma, and also for ternary materials such as HfSiO x . 10 , 11 , 46 − 48 Moreover, from a mechanistic point of view, the low-pressure PEALD process of SiO 2 from BDEAS and O 2 plasma is one of the most thoroughly studied, theoretically as well as experimentally. 10 , 11 , 41 For this particular precursor, Baek et al calculated that adsorption on −OH surface groups indeed takes place through Si–N bond breaking followed by the protonation of amine ligands −N(C 2 H 5 ) 2 to volatile diethylamine molecules (NH(C 2 H 5 ) 2 , DEA).…”

Section: Concise Overview On the Ald Reaction Mechanism Of Sio 2 Using Aminosilane Precursorsmentioning

confidence: 99%

Atmospheric-Pressure Plasma-Enhanced Spatial ALD of SiO₂ Studied by Gas-Phase Infrared and Optical Emission Spectroscopy

et al. 2021

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An atmospheric-pressure plasma-enhanced spatial atomic layer deposition (PE-s-ALD) process for SiO2 using bisdiethylaminosilane (BDEAS, SiH2[NEt2]2) and O2 plasma is reported along with an investigation of its underlying growth mechanism. Within the temperature range of 100–250 °C, the process demonstrates self-limiting growth with a growth per cycle (GPC) between 0.12 and 0.14 nm and SiO2 films exhibiting material properties on par with those reported for low-pressure PEALD. Gas-phase infrared spectroscopy on the reactant exhaust gases and optical emission spectroscopy (OES) on the plasma region are used to identify the species that are involved in the ALD process. Based on the identified species, we propose a reaction mechanism where BDEAS molecules adsorb on −OH surface sites through the exchange of one of the amine ligands upon desorption of diethylamine (DEA). The remaining amine ligand is removed through combustion reactions activated by the O2 plasma species leading to the release of H2O, CO2, and CO in addition to products such as N2O, NO2, and CH-containing species. These volatile species can undergo further gas-phase reactions in the plasma as indicated by the observation of OH*, CN*, and NH* excited fragments in OES. Furthermore, the infrared analysis of the precursor exhaust gas indicated the release of CO2 during precursor adsorption. Moreover, this analysis has allowed the quantification of the precursor depletion yielding values between 10 and 50% depending on the processing parameters. Besides providing insights into the chemistry of atmospheric-pressure PE-s-ALD of SiO2, our results demonstrate that infrared spectroscopy performed on exhaust gases is a valuable approach to quantify relevant process parameters, which can ultimately help evaluate and improve process performance.

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“…N 2 and H 2 can indeed lead to nitrides when they are injected separately or as a mixture in a plasma-assisted process. This deposition mode has resulted in various nitride thin films such as InN 25 , AlN 26 , TaN x 27,28 , SiN x 29 , HfN x 30 , ZrN x 30 and TiN [31][32][33][34][35][36][37][38][39] . Although NH 3 molecule exhibits high reactivity, several studies also report plasma-enhanced processes using this chemical because it may lead to reduced resistivity and contamination [40][41][42] .…”

Section: Introductionmentioning

confidence: 99%

Conductive TiN thin films grown by plasma-enhanced atomic layer deposition: Effects of N-sources and thermal treatments

Badie

Tissot

Sciacca

et al. 2023

Journal of Vacuum Science &Amp; Technology A

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This work consists of optimizing TiN plasma-enhanced atomic layer deposition using two different N-sources: NH[Formula: see text] and N[Formula: see text]. In addition to maximizing the growth per cycle (GPC) and to shorten the deposition duration, comprehensive in situ and ex situ physicochemical characterizations give valuable information about the influence of the N-source nature, their dilution in Ar, and the plasma power on layer’s final properties. N[Formula: see text] and NH[Formula: see text] dilutions within Ar are extensively investigated since they are critical to decreasing the mean free path ([Formula: see text]) of plasma-activated species. A 1:1 gas ratio for the N-sources:Ar mixture associated with low flows (20 sccm) is optimal values for achieving highest GPCs (0.8 Å/cycle). Due to lower reactivity and shorter [Formula: see text] of the excited species, N[Formula: see text] plasma is more sensitive to power and generator-to-sample distance, and this contributes to lower conformality than with NH[Formula: see text] plasma. The resistivity of the initial amorphous films was high ([Formula: see text] cm) and was significantly reduced after thermal treatment ([Formula: see text] cm). This demonstrates clearly the beneficial effect of the crystallinity of the film conductivity. Though N[Formula: see text] process appears slightly slower than the NH[Formula: see text] one, it leads to an acceptable film quality. It should be considered since it is nonharmful, and the process could be further improved by using a reactor exhibiting optimized geometry.

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Surface reactions of aminosilane precursors during N₂ plasma‐assisted atomic layer deposition of SiN_x

Cited by 12 publications

References 55 publications

Atomic Layer Deposition of Wet-Etch Resistant Silicon Nitride Using Di(sec-butylamino)silane and N₂Plasma on Planar and 3D Substrate Topographies

Atomic Layer Deposition of Wet-Etch Resistant Silicon Nitride Using Di(sec-butylamino)silane and N₂Plasma on Planar and 3D Substrate Topographies

Atmospheric-Pressure Plasma-Enhanced Spatial ALD of SiO₂ Studied by Gas-Phase Infrared and Optical Emission Spectroscopy

Conductive TiN thin films grown by plasma-enhanced atomic layer deposition: Effects of N-sources and thermal treatments

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Surface reactions of aminosilane precursors during N2 plasma‐assisted atomic layer deposition of SiNx

Cited by 12 publications

References 55 publications

Atomic Layer Deposition of Wet-Etch Resistant Silicon Nitride Using Di(sec-butylamino)silane and N2Plasma on Planar and 3D Substrate Topographies

Atomic Layer Deposition of Wet-Etch Resistant Silicon Nitride Using Di(sec-butylamino)silane and N2Plasma on Planar and 3D Substrate Topographies

Atmospheric-Pressure Plasma-Enhanced Spatial ALD of SiO2 Studied by Gas-Phase Infrared and Optical Emission Spectroscopy

Conductive TiN thin films grown by plasma-enhanced atomic layer deposition: Effects of N-sources and thermal treatments

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Surface reactions of aminosilane precursors during N₂ plasma‐assisted atomic layer deposition of SiN_x

Atomic Layer Deposition of Wet-Etch Resistant Silicon Nitride Using Di(sec-butylamino)silane and N₂Plasma on Planar and 3D Substrate Topographies

Atomic Layer Deposition of Wet-Etch Resistant Silicon Nitride Using Di(sec-butylamino)silane and N₂Plasma on Planar and 3D Substrate Topographies

Atmospheric-Pressure Plasma-Enhanced Spatial ALD of SiO₂ Studied by Gas-Phase Infrared and Optical Emission Spectroscopy