Low resistivity, super-saturation phosphorus-in-silicon monolayer doping

McKibbin, Sarah R.; Polley, Craig; Scappucci, Giordano; Keizer, J. G.; Simmons, M. Y.

doi:10.1063/1.4869111

Cited by 30 publications

(55 citation statements)

References 25 publications

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“…Phosphine (PH 3 ) is a common source of phosphorus in the chemical vapor deposition of n-type silicon for the semiconductor industry [1]. The dissociation chemistry of PH 3 on the silicon (001) surface is therefore of considerable technological relevance and has been the subject of numerous experimental [2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20] and theoretical studies [16][17][18][21][22][23][24][25][26][27][28][29].…”

Section: Introductionmentioning

confidence: 99%

Reaction paths of phosphine dissociation on silicon (001)

Warschkow

Curson

Schofield

et al. 2016

The Journal of Chemical Physics

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Using density functional theory and guided by extensive scanning tunneling microscopy (STM) image data, we formulate a detailed mechanism for the dissociation of phosphine (PH3) molecules on the Si(001) surface at room temperature. We distinguish between a main sequence of dissociation that involves PH2+H, PH+2H, and P+3H as observable intermediates, and a secondary sequence that gives rise to PH+H, P+2H, and isolated phosphorus adatoms. The latter sequence arises because PH2 fragments are surprisingly mobile on Si(001) and can diffuse away from the third hydrogen atom that makes up the PH3 stoichiometry. Our calculated activation energies describe the competition between diffusion and dissociation pathways and hence provide a comprehensive model for the numerous adsorbate species observed in STM experiments.

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Section: Introductionmentioning

confidence: 99%

Reaction paths of phosphine dissociation on silicon (001)

Warschkow

Curson

Schofield

et al. 2016

The Journal of Chemical Physics

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“…correspond to a 'standard' single-dose Si:P δ-layer with <1/4 of a monolayer (ML) of P dopants in an almost atomically sharp plane. Figure 2b corresponds to a similarly sharp 'double dose' with dopant density >1/4 ML and increased disorder 20 . Figure 2c corresponds to a 'thick' (1.5 nm) region with a similar (i.e., ≈25%) doping concentration (see Supplementary Information).…”

Section: Minmentioning

confidence: 89%

The sub-band structure of atomically sharp dopant profiles in silicon

et al. 2020

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The downscaling of silicon-based structures and proto-devices has now reached the single-atom scale, representing an important milestone for the development of a silicon-based quantum computer. One especially notable platform for atomic-scale device fabrication is the so-called Si:P δ-layer, consisting of an ultra-dense and sharp layer of dopants within a semiconductor host. Whilst several alternatives exist, it is on the Si:P platform that many quantum proto-devices have been successfully demonstrated. Motivated by this, both calculations and experiments have been dedicated to understanding the electronic structure of the Si:P δ-layer platform. In this work, we use high-resolution angle-resolved photoemission spectroscopy to reveal the structure of the electronic states which exist because of the high dopant density of the Si:P δ-layer. In contrast to published theoretical work, we resolve three distinct bands, the most occupied of which shows a large anisotropy and significant deviation from simple parabolic behaviour. We investigate the possible origins of this fine structure, and conclude that it is primarily a consequence of the dielectric constant being large (ca. double that of bulk Si). Incorporating this factor into tight-binding calculations leads to a major revision of band structure; specifically, the existence of a third band, the separation of the bands, and the departure from purely parabolic behaviour. This new understanding of the band structure has important implications for quantum proto-devices which are built on the Si:P δ-layer platform.

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“…To date, most reports focus on studying the influence of surface chemistry used, molecular footprint, and details of capping layer used on the resulting doping levels. [ 18,27–32 ] The application of phenylboronic acid (PBA) monolayers in doping was previously studied, in part, for the formation of sharp p–i–n junctions in SiNWs, [ 17 ] for studying dopant diffusion and activation in SiNWs, [ 33 ] and for dopant patterning. [ 34 ] Herein, a systematic study to understand the impact of oxide cap deposition on the B‐doping by PBA monolayer is presented.…”

Section: Introductionmentioning

confidence: 99%

Boron Monolayer Doping: Role of Oxide Capping Layer, Molecular Fragmentation, and Doping Uniformity at the Nanoscale

Tzaguy

Karadan

Killi

et al. 2020

Adv Materials Inter

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Doping methodologies using monolayers offer controlled, ex situ doping of nanowires (NWs), and 3D device architectures using molecular monolayers as dopant sources with uniform, self‐limiting characteristics. Comparing doping levels and uniformity for boron‐containing monolayers using different methodologies demonstrates the effects of oxide capping on doping performances following rapid thermal anneal (RTA). Strikingly, for noncovalent monolayers of phenylboronic acid (PBA), highest doping levels are obtained with minimal thermal budget without applying oxide capping. Monolayer damage and entrapment of molecular fragments in the oxide capping layer account for the lower performance caused by thermal damage to the PBA monolayer, which results in transformation of the monolayer source to a thin solid source layer. The impact of the oxide capping procedure is demonstrated by a series of experiments. Details of monolayer fragmentation processes and its impact on doping uniformity at the nanoscale are addressed for two types of surface chemistries by applying Kelvin probe force microscopy (KPFM). These results point at the importance of molecular decomposition processes for monolayer‐based doping methodologies, both during preanneal capping step and during rapid thermal processing step. These are important guidelines to be considered for future developments of appropriate surface chemistry used in monolayer doping applications.

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Low resistivity, super-saturation phosphorus-in-silicon monolayer doping

Cited by 30 publications

References 25 publications

Reaction paths of phosphine dissociation on silicon (001)

Reaction paths of phosphine dissociation on silicon (001)

The sub-band structure of atomically sharp dopant profiles in silicon

Boron Monolayer Doping: Role of Oxide Capping Layer, Molecular Fragmentation, and Doping Uniformity at the Nanoscale

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