skip to main content

Title: Tensile strained Ge tunnel field-effect transistors: k · p material modeling and numerical device simulation

Group IV based tunnel field-effect transistors generally show lower on-current than III-V based devices because of the weaker phonon-assisted tunneling transitions in the group IV indirect bandgap materials. Direct tunneling in Ge, however, can be enhanced by strain engineering. In this work, we use a 30-band k · p method to calculate the band structure of biaxial tensile strained Ge and then extract the bandgaps and effective masses at Γ and L symmetry points in k-space, from which the parameters for the direct and indirect band-to-band tunneling (BTBT) models are determined. While transitions from the heavy and light hole valence bands to the conduction band edge at the L point are always bridged by phonon scattering, we highlight a new finding that only the light-hole-like valence band is strongly coupling to the conduction band at the Γ point even in the presence of strain based on the 30-band k · p analysis. By utilizing a Technology Computer Aided Design simulator equipped with the calculated band-to-band tunneling BTBT models, the electrical characteristics of tensile strained Ge point and line tunneling devices are self-consistently computed considering multiple dynamic nonlocal tunnel paths. The influence of field-induced quantum confinement on the tunneling onset is included. Our simulation predictsmore » that an on-current up to 160 (260) μA/μm can be achieved along with on/off ratio > 10{sup 6} for V{sub DD} = 0.5 V by the n-type (p-type) line tunneling device made of 2.5% biaxial tensile strained Ge.« less
Authors:
;  [1] ;  [2] ;  [1] ; ; ;  [1] ;  [2] ;  [3]
  1. IMEC, Kapeldreef 75, 3001 Leuven (Belgium)
  2. (Belgium)
  3. Department of Materials Science and Engineering, University of Texas at Dallas, Richardson, Texas 75080 (United States)
Publication Date:
OSTI Identifier:
22275656
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 115; Journal Issue: 4; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; COMPUTER-AIDED DESIGN; COMPUTERIZED SIMULATION; COUPLING; ELECTRONIC STRUCTURE; ENERGY GAP; FIELD EFFECT TRANSISTORS; GERMANIUM COMPOUNDS; HOLES; N-TYPE CONDUCTORS; PHONONS; SIMULATORS; STRAINS; TUNNEL EFFECT; VALENCE