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Effect of interface dipole on channel engineering and on direct tunneling current in double gate MOSFET
Author(s) -
Prasad B.,
Vohra Anil
Publication year - 2020
Publication title -
international journal of numerical modelling: electronic networks, devices and fields
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.249
H-Index - 30
eISSN - 1099-1204
pISSN - 0894-3370
DOI - 10.1002/jnm.2754
Subject(s) - quantum tunnelling , work function , metal gate , gate dielectric , time dependent gate oxide breakdown , mosfet , gate oxide , materials science , dipole , high κ dielectric , condensed matter physics , acceptor , optoelectronics , dielectric , transistor , nanotechnology , physics , voltage , quantum mechanics , layer (electronics)
In the present work, the effects of interface dipoles on channel engineering and on direct tunneling current have been studied for a double gate (DG) NMOSFET with Si and In 0.53 Ga 0.47 As as channel materials. The gate tunneling current ( I G ) has been calculated for both type of devices and simulation results are reported using Silvaco ATLAS 3D TCAD. A gate length of 10 nm has been used for the simulations. All simulations have been carried out by considering the Direct Quantum Tunneling current model along with the self‐consistent solution of Schrödinger's equation with Poisson's equation. The wavefunction penetration into SiO 2 has also been considered. Fermi Dirac statistics has been used in case of heavy acceptor doping of channel region in the devices studied. The effects of high‐ k material, metal gate work function, and P + channel doping variation on I G have also been studied. The calculations of I G have been carried out using SiO 2 (0.8 nm thickness), and with its equivalent oxide thickness (EOT) using SiO 2 + HfO 2 (0.7 nm + 0.641 nm ) . In case of SiO 2 + HfO 2 , changes in dipole moment at interface take place and lead to the change in work function of metal gates. This has been considered under interface dipole effects. It has been observed that I G of the NMOSFET decreases when high‐k material is used as gate dielectric. Also, the gate metal with high work function and heavy acceptor type doping of channel results in decrease in I G . There is a further reduction in I G by including the interface dipoles effect.