Shallow Trap States Control Electrical Performance of Amorphous Oxide Semiconductor Thin-Film Transistors

Fuente: arXiv
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Main Authors: Mattsson, Måns J., Lee, Jinhan, Malmberg, Christopher E., Parker, Jared, Vogt, Kyle T., Kim, Hyemi, Hong, Minji, Yun, Pilsang, Ha, Daewon, Lee, Taeyoon, Cheong, Paul H. -Y., Wager, John F., Graham, Matt W.
Format: Preprint
Published: 2026
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author Mattsson, Måns J.
Lee, Jinhan
Malmberg, Christopher E.
Parker, Jared
Vogt, Kyle T.
Kim, Hyemi
Hong, Minji
Yun, Pilsang
Ha, Daewon
Lee, Taeyoon
Cheong, Paul H. -Y.
Wager, John F.
Graham, Matt W.
author_facet Mattsson, Måns J.
Lee, Jinhan
Malmberg, Christopher E.
Parker, Jared
Vogt, Kyle T.
Kim, Hyemi
Hong, Minji
Yun, Pilsang
Ha, Daewon
Lee, Taeyoon
Cheong, Paul H. -Y.
Wager, John F.
Graham, Matt W.
contents The performance of n-type amorphous oxide semiconductor thin-film transistors (TFTs) is largely controlled by the density of states (DoS) near the conduction band mobility edge. Here, the full subgap DoS of amorphous InGaZnO (a-IGZO) TFTs, used in display panels and dynamic random-access memory (DRAM) development, is measured by ultrabroadband photoconduction (UP-DoS) microscopy to within 0.1 eV of the mobility edge. The measured subgap DoS for 25 TFT processing conditions accurately predicts each transfer curve, showing how shallow defect states are electron traps that rigidly tune subthreshold swing, threshold voltage and drift mobility. For a set of TFTs, the subthreshold transfer characteristics can be independently simulated from the experimental shallow defect DoS, with no adjustable parameters. The full transfer curve is simulated by introducing a single parameter: the conduction band tail energy. Additionally, the simulation reveals that the shallow trap density controlling subthreshold behavior can be directly extracted from transfer curves. Finally, a systematic In-enrichment study, combined with DFT+U DoS simulations, enables identification of vacancy cation coordination environments for all experimentally observed subgap peaks. The dominant trap controlling conventional a-IGZO TFT performance is centered at ~0.32 eV below the conduction band mobility edge and is assigned to a Ga-Ga-In oxygen vacancy defect.
format Preprint
id arxiv_https___arxiv_org_abs_2602_06329
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Shallow Trap States Control Electrical Performance of Amorphous Oxide Semiconductor Thin-Film Transistors
Mattsson, Måns J.
Lee, Jinhan
Malmberg, Christopher E.
Parker, Jared
Vogt, Kyle T.
Kim, Hyemi
Hong, Minji
Yun, Pilsang
Ha, Daewon
Lee, Taeyoon
Cheong, Paul H. -Y.
Wager, John F.
Graham, Matt W.
Applied Physics
Materials Science
Instrumentation and Detectors
The performance of n-type amorphous oxide semiconductor thin-film transistors (TFTs) is largely controlled by the density of states (DoS) near the conduction band mobility edge. Here, the full subgap DoS of amorphous InGaZnO (a-IGZO) TFTs, used in display panels and dynamic random-access memory (DRAM) development, is measured by ultrabroadband photoconduction (UP-DoS) microscopy to within 0.1 eV of the mobility edge. The measured subgap DoS for 25 TFT processing conditions accurately predicts each transfer curve, showing how shallow defect states are electron traps that rigidly tune subthreshold swing, threshold voltage and drift mobility. For a set of TFTs, the subthreshold transfer characteristics can be independently simulated from the experimental shallow defect DoS, with no adjustable parameters. The full transfer curve is simulated by introducing a single parameter: the conduction band tail energy. Additionally, the simulation reveals that the shallow trap density controlling subthreshold behavior can be directly extracted from transfer curves. Finally, a systematic In-enrichment study, combined with DFT+U DoS simulations, enables identification of vacancy cation coordination environments for all experimentally observed subgap peaks. The dominant trap controlling conventional a-IGZO TFT performance is centered at ~0.32 eV below the conduction band mobility edge and is assigned to a Ga-Ga-In oxygen vacancy defect.
title Shallow Trap States Control Electrical Performance of Amorphous Oxide Semiconductor Thin-Film Transistors
topic Applied Physics
Materials Science
Instrumentation and Detectors
url https://arxiv.org/abs/2602.06329