Mobility and threshold voltage extraction in transistors with gate-voltage-dependent contact resistance

Abstract The mobility of emerging (e.g., two-dimensional, oxide, organic) semiconductors is commonly estimated from transistor current-voltage measurements. However, such devices often experience contact gating, i.e., electric fields from the gate modulate the contact resistance during measurements,...

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Bibliographic Details
Main Authors: Robert K. A. Bennett, Lauren Hoang, Connor Cremers, Andrew J. Mannix, Eric Pop
Format: Article
Language:English
Published: Nature Portfolio 2025-02-01
Series:npj 2D Materials and Applications
Online Access:https://doi.org/10.1038/s41699-024-00506-4
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Summary:Abstract The mobility of emerging (e.g., two-dimensional, oxide, organic) semiconductors is commonly estimated from transistor current-voltage measurements. However, such devices often experience contact gating, i.e., electric fields from the gate modulate the contact resistance during measurements, which can lead conventional extraction techniques to estimate mobility incorrectly even by a factor >2. Although this error can be minimized by measuring transistors at high gate-source bias |V gs|, this regime is often inaccessible in emerging devices that suffer from high contact resistance or early gate dielectric breakdown. Here, we propose a method of extracting mobility in transistors with gate-dependent contact resistance that does not require operation at high |V gs|, enabling accurate mobility extraction even in emerging transistors with strong contact gating. Our approach relies on updating the transfer length method (TLM) and can achieve <10% error even in regimes where conventional techniques overestimate mobility by >2×.
ISSN:2397-7132