Growth and electrical properties of silicon oxide grown by atomic layer deposition using Bis(ethyl-methyl-amino)silane and ozone

Abstract

Silicon oxide thin film grown at low temperatures (<300–500 °C) is essential for a range of applications in semiconductor devices. In this study, silicon oxide films were deposited at a substrate temperature of ∼300 °C by an atomic layer deposition (ALD) process using Bis(ethyl-methyl-amino)silane (BEMAS). BEMAS precursors adsorbed on the growing surface reacted with ozone but not with H2O. This suggests that the Si–H bonds in the BEMAS precursors adsorbed on the surface are robust and could be cleaved only by ozone. The reaction using BEMAS and ozone exhibited ALD saturation behavior. The dielectric constant of the ALD-SiO2 was measured to be ∼9, which is 2.3 times higher than that (∼3.9) of normal amorphous SiO2. This was attributed to the existence of the ∼10% OH species in the film.

Modeling Mechanism and Growth Reactions for New Nanofabrication Processes by Atomic Layer Deposition

“…[ 65 ] Although chlorosilanes (e.g., SiCl 4 , SiH 2 Cl 2 and Si 2 Cl 6 ) are currently used for ALD of silicon nitride with NH 3 or N 2 as nitrogen source, [57][58][59]66,67 ] a chlorine-free low-temperature CVD or, ideally, ALD process would be preferred for many applications. Finding alternative Si precursors, and optimizing existing families such as aminosilanes, is therefore the motivation for some of the theoretical work presented here and for ongoing research.…”

Design of efficient mono-aminosilane precursors for atomic layer deposition of SiO2 thin films

“…Similarly, through the introduction of an amino group, aminosilane precursors play an important role of self-catalysing in Si-O formation of SiO 2 ALD. 12,25 Recently, various alkylaminosilane-based molecules with appropriately reactive functional ligands have been evaluated and tested with the aim to identify most suitable precursors for SiO 2 thin lm growth both experimentally [26][27][28][29][30][31][32] and theoretically. [15][16][17][33][34][35] It was found that an increase in the degree of alkylamino substitution on Si atom would result in a reduced deposition rate and a use of tris(alkylamino)silane-based precursors may lead to a higher degree of impurity in the lms, especially in a low temperature range of the ALD window.…”

Selective Growth and Contact Gap-Fill of Low Resistivity Si via Microwave Plasma-Enhanced CVD

“…Figure 5a shows a conventional X-TEM image of a 20 nm pitch DRAM gBC pattern after Si gap-filling and etching back (including additional thermal nitride deposition and etching-back). Though the amino-silane was used for uniform nucleation before thermal CVD growth [1], there were large voids near the interface between the active Si and the thermal grown Si, because Si was simultaneously grown from the bottom active Si and the side wall dielectric. The TEM image also shows that the thermal grown amorphous Si at the contact area was crystallized, thus forming the CEG due to the thermal process (~800 °C) of the following nitride deposition.…”

“…The main reasons for this limitation are seam and void formation near the middle of the contact area, which results from higher doping concentrations. Numerous alternative solutions for these difficulties have been proposed, such as thermal CVD with an amino-silane seed layer [1], Si implantation after Si etch-back, flowable CVD and laser-induced epitaxial growth [2]. However, all of these methods cannot meet simultaneously requirements.…”