Sub-Thermionic Switching in a Negative-Capacitance Bandgap-Change Field-Effect Transistor
Abstract
Overcoming the approximately 60~mV/dec Boltzmann limit of the subthreshold swing remains a central challenge for low-power nanoelectronics. Negative-capacitance field-effect transistors address it by amplifying the channel potential, but their effectiveness is constrained by capacitance matching and by the quantum capacitance of conventional channels. Here we model a negative-capacitance bandgap-change field-effect transistor (NC-BCFET), in which the ferroelectric gate stack instead amplifies the electric field that opens the bandgap of the channel, using experimentally proven materials: bilayer graphene as a channel with an electrically tunable bandgap and Al0.55Sc0.45N as the negative-capacitance ferroelectric. Our self-consistent framework couples a four-band tight-binding Hamiltonian with GW-corrected screening, a quasistatic Landau--Devonshire ferroelectric response, and ballistic Landauer--Büttiker transport. Negative capacitance amplifies the interlayer potential difference, compressing the switching window 37-fold relative to a dielectric-gated control. At 300~K, the optimized NC-BCFET achieves a subthreshold swing of 15~mV/dec, four times below the Boltzmann limit, improving to 2.5~mV/dec at 100~K. The room-temperature on/off ratio is limited to ∼ 102 by the bandgap of bilayer graphene. The concept extends directly to materials with larger field-tunable bandgaps, where deep subthermionic switching and high on/off ratios can be achieved together at room temperature.
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BibTeX
@misc{awale2026subthermionic,
title = {{Sub-Thermionic Switching in a Negative-Capacitance Bandgap-Change Field-Effect Transistor}},
author = {Rahul B Awale and Mike Klymenko and Yuefeng Yin and Nikhil V Medhekar and Bhaskaran Muralidharan and Michael S Fuhrer},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.23505},
eprint = {2609.23505},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.23505},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Sub-Thermionic Switching in a Negative-Capacitance Bandgap-Change Field-Effect Transistor
AU - Rahul B Awale
AU - Mike Klymenko
AU - Yuefeng Yin
AU - Nikhil V Medhekar
AU - Bhaskaran Muralidharan
AU - Michael S Fuhrer
PY - 2026
DA - 2026/09/20
PB - arXiv
DO - 10.48550/arxiv.2609.23505
UR - https://arxiv.org/abs/2609.23505
AB - Overcoming the approximately 60~mV/dec Boltzmann limit of the subthreshold swing remains a central challenge for low-power nanoelectronics. Negative-capacitance field-effect transistors address it by amplifying the channel potential, but their effectiveness is constrained by capacitance matching and by the quantum capacitance of conventional channels. Here we model a negative-capacitance bandgap-change field-effect transistor (NC-BCFET), in which the ferroelectric gate stack instead amplifies the electric field that opens the bandgap of the channel, using experimentally proven materials: bilayer graphene as a channel with an electrically tunable bandgap and Al_0.55Sc_0.45N as the negative-capacitance ferroelectric. Our self-consistent framework couples a four-band tight-binding Hamiltonian with GW-corrected screening, a quasistatic Landau--Devonshire ferroelectric response, and ballistic Landauer--Büttiker transport. Negative capacitance amplifies the interlayer potential difference, compressing the switching window 37-fold relative to a dielectric-gated control. At 300~K, the optimized NC-BCFET achieves a subthreshold swing of 15~mV/dec, four times below the Boltzmann limit, improving to 2.5~mV/dec at 100~K. The room-temperature on/off ratio is limited to ∼ 10^2 by the bandgap of bilayer graphene. The concept extends directly to materials with larger field-tunable bandgaps, where deep subthermionic switching and high on/off ratios can be achieved together at room temperature.
ER -