Diagnosis of phosphorus monolayer doping in silicon based on nanowire electrical characterisation

Duffy, Ray; Ricchio, Alessio; Murphy, R.A.; Maxwell, Graeme; Murphy, Richard J.; Piaszenski, Guido; Petkov, Nikolay; Hydes, A.J.; O’Connell, Dan; Lyons, Colin; Kennedy, Noel; Sheehan, Brendan; Schmidt, Michael; Crupi, Felice; Holmes, Justin D.; Hurley, Paul K.; Connolly, J.P.; Hatem, C.; Long, Brenda

doi:10.1063/1.5019470

Cited by 20 publications

(17 citation statements)

References 65 publications

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“…Considerable broadening of dopant profiles from drain/source regions into gate areas persists even when using self-regulatory plasma doping combined with rapid spike annealing [3]. To add, required ULSI transistor functionality [4] and emerging applications of Sinanocrystals (NCs) [5] unveiled additional doping issues such as self-purification [6,7], dopant ionization failing at room temperature [8,9] and dopant-associated defect states [9][10][11][12].…”

Section: Introductionmentioning

confidence: 99%

Electronic Structure Shift of Deeply Nanoscale Silicon by SiO2 versus Si3N4
König
¹
,
Wilck
²
,
Hiller
³

et al. 2019
Phys. Rev. Applied
10
2
43
0
1
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Conventional impurity doping of deep nanoscale silicon (dns-Si) used in ultra large scale integration (ULSI) faces serious challenges below the 14 nm technology node. We report on a new fundamental effect in theory and experiment, namely the electronic structure of dns-Si experiencing energy offsets of ca. 1 eV as a function of SiO2-vs. Si3N4-embedding with a few monolayers (MLs). An interface charge transfer (ICT) from dns-Si specific to the anion type of the dielectric is at the core of this effect and arguably nested in quantum-chemical properties of oxygen (O) and nitrogen (N) vs. Si. We investigate the size up to which this energy offset defines the electronic structure of dns-Si by density functional theory (DFT), considering interface orientation, embedding layer thickness, and approximants featuring two Si nanocrystals (NCs); one embedded in SiO2 and the other in Si3N4. Working with synchrotron ultraviolet photoelectron spectroscopy (UPS), we use SiO2-vs. Si3N4-embedded Si nanowells (NWells) to obtain their energy of the top valence band states. These results confirm our theoretical findings and gauge an analytic model for projecting maximum dns-Si sizes for NCs, nanowires (NWires) and NWells where the energy offset reaches full scale, yielding to a clear preference for electrons or holes as majority carriers in dns-Si. Our findings can replace impurity doping for n/p-type dns-Si as used in ultra-low power electronics and ULSI, eliminating dopant-related issues such as inelastic carrier scattering, thermal ionization, clustering, out-diffusion and defect generation. As far as majority carrier preference is concerned, the elimination of those issues effectively shifts the lower size limit of Si-based ULSI devices to the crystalization limit of Si of ca. 1.5 nm and enables them to work also under cryogenic conditions. *

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Section: Introductionmentioning

confidence: 99%

Electronic Structure Shift of Deeply Nanoscale Silicon by SiO2 versus Si3N4
König
¹
,
Wilck
²
,
Hiller
³

et al. 2019
Phys. Rev. Applied
10
2
43
0
1
View full text Add to dashboard Cite

show abstract

“…Figure 3 a shows the SRP results obtained on four different samples doped with PA and processed at the annealing temperature of 1050 °C for 20 s, after the MD deposition. The dose of carriers obtained by integrating the reported profiles is as high as 3 × 10 15 #/cm 2 , indicating an outstanding yield compared to both traditional and MD methods [ 1 , 2 , 3 , 4 , 5 , 6 , 7 ]. The peak of the charge carriers is 1 × 10 20 #/cm 3 .…”

Section: Resultsmentioning

confidence: 99%

“…Recently, an alternative method of doping has been proposed based on the use of liquid solutions, the Molecular Doping (MD) [ 1 , 2 , 3 , 4 , 5 , 6 , 7 ]. The dopant precursor is in liquid form, and the semiconductor (e.g., silicon, germanium, or gallium arsenide) is immersed in the solution.…”

Section: Introductionmentioning

confidence: 99%

Carbon-Free Solution-Based Doping for Silicon

Caccamo

Puglisi

2021

Nanomaterials

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Molecular doping is a method to dope semiconductors based on the use of liquid solutions as precursors of the dopant. The molecules are deposited on the material, forming a self-ordered monolayer that conforms to the surfaces, whether they are planar or structured. So far, molecular doping has been used with precursors of organic molecules, which also release the carbon in the semiconductor. The carbon atoms, acting as traps for charge carriers, deteriorate the doping efficiency. For rapid and extensive industrial exploitation, the need for a method that removes carbon has therefore been raised. In this paper, we use phosphoric acid as a precursor of the dopant. It does not contain carbon and has a smaller steric footprint than the molecules used in the literature, thus allowing a much higher predetermined surface density. We demonstrate doses of electrical carriers as high as 3 × 1015 #/cm2, with peaks of 1 × 1020 #/cm3, and high repeatability of the process, indicating an outstanding yield compared to traditional MD methods.

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“…For example, in our recent report, at least 20% of phosphorus atoms were deactivated by forming interstitial carbon–substitutional phosphorus (C i –P s ) defects. 7 Duffy et al also reported 8 that Si nanowires doped by the SAMM process have a lower dopant activation rate when compared to the devices doped with the standard ion implantation, likely because of the carbon-related defects introduced by the dopant carrier molecules. Hence, it is extremely important to develop a defect-free SAMM-doping technique, in particular for commercial applications in the state-of-the-art fin field-effect transistors.…”

Section: Introductionmentioning

confidence: 99%

Toward Defect-Free Doping by Self-Assembled Molecular Monolayers: The Evolution of Interstitial Carbon-Related Defects in Phosphorus-Doped Silicon

et al. 2019

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Self-assembled molecular monolayer (SAMM) doping on semiconductors has been widely appraised for its advantages of doping nanoelectronic devices for applications in the complementary metal-oxide-semiconductor transistor (CMOS) industry. However, defects introduced by SAMM-doping will limit the performance of the devices. Previously, we have found that SAMM-doping can bring carbon impurities into the silicon substrate and these unwanted carbon impurities can deactivate phosphorus dopants by forming an interstitial carbon (C i )–substitutional phosphorus (C i –P s ) complex. Herein, to develop a defect-free SAMM-doping process, the generation and annihilation of C i -related defects are investigated by extending the thermal annealing time from 2 to 10 min using secondary ion mass spectrometry and deep-level transient spectroscopy. The results show that the concentration of C i -related carbon defects is lower after a longer time of thermal annealing, although a longer annealing time actually introduces a higher concentration of carbon impurities into Si. This observation indicates that interstitial carbon evolves into substitutional carbon (C s ) that is electrically inactive during the thermal annealing process. A defect-free SAMM-doping process may be developed by an appropriate post-annealing process.

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Diagnosis of phosphorus monolayer doping in silicon based on nanowire electrical characterisation

Cited by 20 publications

References 65 publications

Electronic Structure Shift of Deeply Nanoscale Silicon by SiO2 versus Si3N4
König
¹
,
Wilck
²
,
Hiller
³

et al. 2019
Phys. Rev. Applied
10
2
43
0
1
View full text Add to dashboard Cite

Electronic Structure Shift of Deeply Nanoscale Silicon by SiO2 versus Si3N4
König
¹
,
Wilck
²
,
Hiller
³

et al. 2019
Phys. Rev. Applied
10
2
43
0
1
View full text Add to dashboard Cite

Carbon-Free Solution-Based Doping for Silicon

Toward Defect-Free Doping by Self-Assembled Molecular Monolayers: The Evolution of Interstitial Carbon-Related Defects in Phosphorus-Doped Silicon

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Diagnosis of phosphorus monolayer doping in silicon based on nanowire electrical characterisation

Cited by 20 publications

References 65 publications

Electronic Structure Shift of Deeply Nanoscale Silicon by SiO2 versus Si3N4König1, Wilck2, Hiller3 et al. 2019Phys. Rev. Applied1024301View full textAdd to dashboardCite

Electronic Structure Shift of Deeply Nanoscale Silicon by SiO2 versus Si3N4König1, Wilck2, Hiller3 et al. 2019Phys. Rev. Applied1024301View full textAdd to dashboardCite

Carbon-Free Solution-Based Doping for Silicon

Toward Defect-Free Doping by Self-Assembled Molecular Monolayers: The Evolution of Interstitial Carbon-Related Defects in Phosphorus-Doped Silicon

Contact Info

Product

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About

Electronic Structure Shift of Deeply Nanoscale Silicon by SiO2 versus Si3N4
König
¹
,
Wilck
²
,
Hiller
³

et al. 2019
Phys. Rev. Applied
10
2
43
0
1
View full text Add to dashboard Cite

Electronic Structure Shift of Deeply Nanoscale Silicon by SiO2 versus Si3N4
König
¹
,
Wilck
²
,
Hiller
³

et al. 2019
Phys. Rev. Applied
10
2
43
0
1
View full text Add to dashboard Cite