Experimental and theoretical investigation of the effect of SiO2 content in gate dielectrics on work function shift induced by nanoscale capping layers

Caraveo-Frescas, J. A.; Wang, H.; Schwingenschlögl, Udo; Alshareef, Husam N.

doi:10.1063/1.4747805

Cited by 4 publications

(1 citation statement)

References 18 publications

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“…If this V FB shift indeed depends on the EOT of the Al 2 O 3 layer, it could imply that charges at the Al 2 O 3 -SiO 2 interface may play a role in the shift, as argued before. 45 These results may seem to contradict those obtained with Ta(TaO x )-Al 2 O 3 interfaces, where a TaO x layer was formed and shown to cause a surface dipole attributed to Ta-O bonds. 22 However, the previous case is different from the Ta 2 O 5 -Al 2 O 3 system in several aspects.…”

Section: B Ta 2 O 5 In Al 2 O 3 -Mos Devicescontrasting

confidence: 45%

The electrostatics of Ta2O5 in Si-based metal oxide semiconductor devices

Kornblum

Meyler

Salzman

et al. 2013

Journal of Applied Physics

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Thin dielectric layers are a prominent route to control the band alignments and effective work function of metal oxide semiconductor (MOS) devices. In this work, the electrostatic effects of thin Ta2O5 layers on the band alignments of MOS devices are examined. A detailed analysis of the physical properties of a thick (∼6 nm) Ta2O5 layer is reported. No significant dipoles at Ta2O5-Al2O3 and Ta2O5-SiO2 interfaces are found, as well as any significant charges inside Ta2O5 layers. When positioned at the interface, Ta2O5 is shown to prevent the formation of band offsets between Al2O3-SiO2, resulting in a shift of 1 ± 0.2 eV versus samples without interfacial Ta2O5. The relatively large magnitude of this shift in the current experimental configuration compared to previous works may indicate the participation of interface charges in the band offset. The possible use for these effects in devices is discussed.

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Section: B Ta 2 O 5 In Al 2 O 3 -Mos Devicescontrasting

confidence: 45%

The electrostatics of Ta2O5 in Si-based metal oxide semiconductor devices

Kornblum

Meyler

Salzman

et al. 2013

Journal of Applied Physics

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Energy Offset Between Silicon Quantum Structures: Interface Impact of Embedding Dielectrics as Doping Alternative

König

Hiller

Gutsch

et al. 2014

Adv Materials Inter

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Ultrasmall silicon (Si) nanoelectronic devices require an energy shift of electronic states for n‐ and p‐conductivity. Nanocrystal self‐purification and out‐diffusion in field effect transistors cause doping to fail. Here, it is shown that silicon dioxide (SiO2) and silicon nitride (Si3N4) create energy offsets of electronic states in embedded Si quantum dots (QDs) in analogy to doping. Density functional theory (DFT), interface charge transfer (ICT), and experimental verifications arrive at the same size of QDs below which the dielectric dominates their electronic properties. Large positive energy offsets of electronic states and an energy gap increase exist for Si QDs in Si3N4 versus SiO2. Using DFT results, the SiO2/QD interface coverage is estimated with nitrogen (N) to be 0.1 to 0.5 monolayers (ML) for samples annealed in N2 versus argon (Ar). The interface impact is described as nanoscopic field effect and propose the energy offset as robust and controllable alternative to impurity doping of Si nanostructures.

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