1. Nitride Dielectric Environments to Suppress Surface Optical Phonon Dominated Scattering in High-Performance Multilayer MoS2 FETs
- Author
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Tathagata Paul, Arindam Ghosh, Shubhadeep Bhattacharjee, Navakanta Bhat, Hareesh Chandrasekar, Srinivasan Raghavan, Sangeneni Mohan, and Kolla Lakshmi Ganapathi
- Subjects
010302 applied physics ,Materials science ,Phonon scattering ,Scattering ,business.industry ,Phonon ,Materials Research Centre ,Physics ,Field effect ,02 engineering and technology ,Dielectric ,Nitride ,021001 nanoscience & nanotechnology ,01 natural sciences ,Electronic, Optical and Magnetic Materials ,Electrical Communication Engineering ,0103 physical sciences ,Electronic engineering ,Centre for Nano Science and Engineering ,Optoelectronics ,Field-effect transistor ,Charge carrier ,0210 nano-technology ,business - Abstract
The ultrathin channel in 2D semiconductors, although playing host to several interesting properties, also renders strong interactions (scattering) of charge carriers with the surrounding medium. The over-arching dominance of surface (interfacial) optical phonons in 2D charge transport and engineering ideal nitride-based dielectric environments for large performance gains is reported. Charge transport in MoS2 field effect transistors (FETs) fabricated on three conventional substrates, SiO2, Al2O3, and HfO2, is contrasted with a newly introduced, CMOS-compatible nitride-based dielectric: aluminum nitride (AlN) by employing semi-classical models which account for charged impurity, surface optical phonon, and intrinsic phonon scattering. Unlike previous reports focused on charge impurity scattering, this work presents a new paradigm of utilizing high optical phonon energies intrinsic to ``stiff `` nitride bonds. This results in substantially lower surface optical phonon scattering in 2D FETs which directly influences peak field effect (FE) mobility, high field mobility degradation, and temperature-dependent mobility. Leveraging on these insights, high-performance sulfur-passivated MoS2 FETs with an optimum all-nitride environment (hexagonal boron nitride/MoS2/AlN) are demonstrated with FE mobility up to 72.8 cm(2) V-1 s(-1). This work is envisioned to address important issues in design of dielectric environments for a host of applications based on 2D materials.
- Published
- 2017