Integrated modeling platform for High-k/alternate channel material heterostructure stacks

Vaidya, Dhirendra; Hegde, Arjun; Lodha, Saurabh; Ganguly, Swaroop; Nainani, Aneesh; Yoshida, N.; Guarini, T.

doi:10.1109/sispad.2015.7292341

Cited by 4 publications

(2 citation statements)

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“…The additional error in the latter bias region is attributed to the fact that the Since the extent of the ionic potential tails beyond the chalcogen lattice sites is comparable to the vdW gap, the electrical thickness of the thin MLs is a few angstroms more than the physical thickness determined by the lattice atom positions. Now it is verified using a finite difference 1D Poisson solver [25] that the thickness of the MLs per se do not impact the electrostatic simulations. However, their increased electrical thickness reduces the effective (electrical) interlayer separation.…”

Section: Resultsmentioning

confidence: 91%

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Electrical-Equivalent van der Waals Gap for Two-Dimensional Bilayers

2018

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Vertical stacks of two-dimensional (2D) materials, separated by the van der Waals gap and held together by the van der Waals forces, are immensely promising for a plethora of nanotechnological applications. Charge control in these stacks may be modeled using either a simple electrostatics approach or a detailed atomistic one. In this paper, we compare these approaches for a gated 2D transition metal dichalcogenide bilayer and show that recently reported electrostatics-based models of this system give large errors in band energy compared to atomistic (Density Functional Theory) simulations. These errors are due to the tails of the ionic potentials that reduce the electricalequivalent van der Waals gap between the 2D layers, and can be corrected by using the reduced gap in the electrostatic model. For a physical van der Waals gap (defined as the chalcogen to chalcogen distance) of 3Å in a 2D bilayer, the electrical-equivalent gap is less than 1Å. For the example of band-to-band tunneling based ultra low-power transistors, this is seen to lead to errors of several hundred millivolts and more in the threshold voltage estimated from electrostatics. arXiv:1803.10009v1 [cond-mat.mes-hall]

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Section: Resultsmentioning

confidence: 91%

“…This would also suggest a finite thickness of the MLs. However, using a 1D finite difference Poisson solver [25] we found that the band alignments in vdW stacks are insensitive to the wave nature of electrons/holes for reasonable values of κ. Therefore we concluded that it is not the spread in the wavefunction that causes the error in the electrostatic model.…”

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confidence: 93%