Title

Degradation of Sub-Threshold Slope in Ultra-Scaled MOSFETs due to Energy Filtering at Source Contact

Publication Date

10-14-2019

Document Type

Conference Proceeding

Department

Electrical Engineering

Publication Title

2019 IEEE SOI-3D-Subthreshold Microelectronics Technology Unified Conference (S3S)

DOI

10.1109/S3S46989.2019.9320746

Abstract

We postulate that in ultra-scaled Field Effect Transistors (FET), such as nanowires in sub-7nm technology, the source contact will act as an energy filter and increase the effective temperature of carriers arriving at the channel barrier. This is due to the absence of inelastic scattering in the short source-contact-to-channel region. As a result, the Sub-threshold Slope (SS) will increase substantially. In this paper, we verify this theory through numerical calculations and Technology Computer-Aided-Design (TCAD) simulations calibrated to quantum solvers for electrostatics. It is found that SS degradation increases as the source metal workfunction increases. In the nanowire simulated, SS increases from 94mV/dec to 109mV/dec for gate length, LG, = 10nm and from 72mV/dec to 88mV/dec for LG = 15nm, representing an increase of effective carrier temperature from 300K to more than 340K.

Funding Sponsor

San José State University

Keywords

Ballistic Transport, Energy Filter, Nanowire, Schottky Contact, Sub-threshold Slope

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