Modeling boron dose loss in sidewall spacer stacks of complementary metal oxide semiconductor transistors

Essa, Z.; Pelletier, B.; Morin, P.; Boulenc, P.; Pakfar, A.; Tavernier, C.; Wacquant, F.; Zechner, Christoph; Juhel, M.; Autran, Jean‐Luc; Cristiano, Fuccio

doi:10.1016/j.sse.2016.08.002

Cited by 7 publications

(2 citation statements)

References 26 publications

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“…B dopants are also known to diffuse into the SiO 2 sidewall spacers at RTA temperatures, resulting in a loss of B dosage. 7 The data presented here demonstrate the feasibility of BN film deposition on either B 2 O 3 or B-Si-oxide substrates and also indicate the potential suitability of even very thin (∼13 ± 0.2 Å thick) BN films as passivation barriers against brief exposures to ambient at room temperature. BN as a capping barrier may prevent upward boron diffusion into the cap at elevated temperatures, thus preventing the loss of dopant concentration.…”

Section: Discussionsupporting

confidence: 52%

“…2 Alumina has been reported to crack when used as a capping barrier at temperatures >673 K, allowing the B 2 O 3 under-layer to oxidize to boric acid. 6 Boron was reported to selectively diffuse into the silicon dioxide sidewall spacer instead of Si during rapid thermal anneal (RTA) treatment at 1273 K. 7 RTA is generally used for activating existing dopants or doping substrates. Silicon dioxide as a capping barrier may result in a significant loss of B dose from Si.…”

Section: Introductionmentioning

confidence: 99%

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Atomic layer deposition of BN as a novel capping barrier for B2O3

Pilli

Jones

Chugh

et al. 2019

Journal of Vacuum Science &Amp; Technology A: Vacuum, Surfaces, and Films

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The deposition of boron oxide (B 2 O 3 ) films on Si and SiO 2 substrates by atomic layer deposition (ALD) is of growing interest in microelectronics for shallow doping of high aspect ratio transistor structures. B 2 O 3 , however, forms volatile boric acid (H 3 BO 3 ) upon ambient exposure, requiring a passivation barrier, for which BN was investigated as a possible candidate. Here, the authors demonstrate in situ deposition of BN by sequential BCl 3 /NH 3 reactions at 600 K on two different oxidized boron substrates: (a) B 2 O 3 deposited using BCl 3 /H 2 O ALD on Si at 300 K ("B 2 O 3 /Si") and (b) a boron-silicon oxide formed by sequential BCl 3 /O 2 reactions at 650 K on SiO 2 followed by annealing to 1000 K ("B-Si-oxide"). X-ray photoelectron spectroscopy (XPS) data demonstrate layer-by-layer growth of BN on B 2 O 3 /Si with an average growth rate of ∼1.4 Å/cycle, accompanied by some B 2 O 3 removal during the first BN cycle. In contrast, continuous BN growth was observed on B-Si-oxide without any reaction with the substrate. XPS data also indicate that the oxide/nitride heterostructures are stable upon annealing in ultrahigh vacuum to >1000 K. XPS data, after the exposure of these heterostructures to ambient, indicate a small amount of BN oxidation at the surface NH x species, with no observable hydroxylation of the underlying oxide films. These results demonstrate that BN films, as thin as 13 Å, are potential candidates for passivating boron oxide films prepared for shallow doping applications.

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Section: Discussionsupporting

confidence: 52%