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Negative threshold voltage shift in an a-IGZO thin film transistor under X-ray irradiation

We investigated the effects of X-ray irradiation on the electrical characteristics of an amorphous In–Ga–Zn–O (a-IGZO) thin film transistor (TFT). The a-IGZO TFT showed a negative threshold voltage (V(TH)) shift of −6.2 V after 100 Gy X-ray irradiation. Based on spectroscopic ellipsometry (SE) and X...

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Autores principales: Kim, Dong-Gyu, Kim, Jong-Un, Lee, Jun-Sun, Park, Kwon-Shik, Chang, Youn-Gyoung, Kim, Myeong-Ho, Choi, Duck-Kyun
Formato: Online Artículo Texto
Lenguaje:English
Publicado: The Royal Society of Chemistry 2019
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9065737/
https://www.ncbi.nlm.nih.gov/pubmed/35515555
http://dx.doi.org/10.1039/c9ra03053k
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author Kim, Dong-Gyu
Kim, Jong-Un
Lee, Jun-Sun
Park, Kwon-Shik
Chang, Youn-Gyoung
Kim, Myeong-Ho
Choi, Duck-Kyun
author_facet Kim, Dong-Gyu
Kim, Jong-Un
Lee, Jun-Sun
Park, Kwon-Shik
Chang, Youn-Gyoung
Kim, Myeong-Ho
Choi, Duck-Kyun
author_sort Kim, Dong-Gyu
collection PubMed
description We investigated the effects of X-ray irradiation on the electrical characteristics of an amorphous In–Ga–Zn–O (a-IGZO) thin film transistor (TFT). The a-IGZO TFT showed a negative threshold voltage (V(TH)) shift of −6.2 V after 100 Gy X-ray irradiation. Based on spectroscopic ellipsometry (SE) and X-ray photoelectron spectroscopy (XPS) analysis, we found that the Fermi energy (E(F)) changes from 2.73 eV to 3.01 eV and that the sub-gap state of D1 and D2 changes near the conduction band minimum (CBM) of the a-IGZO film after X-ray irradiation. These results imply that the negative V(TH) shift after X-ray irradiation is related to the increase in electron concentration of the a-IGZO TFT active layer. We confirmed that the sources for electron generation during X-ray irradiation are hydrogen incorporation from the adjacent layer or from ambient air to the active layer in the TFT, and the oxygen vacancy dependent persistent photocurrent (PPC) effect. Since both causes are reversible processes involving an activation energy, we demonstrate the V(TH) shift recovery by thermal annealing.
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spelling pubmed-90657372022-05-04 Negative threshold voltage shift in an a-IGZO thin film transistor under X-ray irradiation Kim, Dong-Gyu Kim, Jong-Un Lee, Jun-Sun Park, Kwon-Shik Chang, Youn-Gyoung Kim, Myeong-Ho Choi, Duck-Kyun RSC Adv Chemistry We investigated the effects of X-ray irradiation on the electrical characteristics of an amorphous In–Ga–Zn–O (a-IGZO) thin film transistor (TFT). The a-IGZO TFT showed a negative threshold voltage (V(TH)) shift of −6.2 V after 100 Gy X-ray irradiation. Based on spectroscopic ellipsometry (SE) and X-ray photoelectron spectroscopy (XPS) analysis, we found that the Fermi energy (E(F)) changes from 2.73 eV to 3.01 eV and that the sub-gap state of D1 and D2 changes near the conduction band minimum (CBM) of the a-IGZO film after X-ray irradiation. These results imply that the negative V(TH) shift after X-ray irradiation is related to the increase in electron concentration of the a-IGZO TFT active layer. We confirmed that the sources for electron generation during X-ray irradiation are hydrogen incorporation from the adjacent layer or from ambient air to the active layer in the TFT, and the oxygen vacancy dependent persistent photocurrent (PPC) effect. Since both causes are reversible processes involving an activation energy, we demonstrate the V(TH) shift recovery by thermal annealing. The Royal Society of Chemistry 2019-07-03 /pmc/articles/PMC9065737/ /pubmed/35515555 http://dx.doi.org/10.1039/c9ra03053k Text en This journal is © The Royal Society of Chemistry https://creativecommons.org/licenses/by/3.0/
spellingShingle Chemistry
Kim, Dong-Gyu
Kim, Jong-Un
Lee, Jun-Sun
Park, Kwon-Shik
Chang, Youn-Gyoung
Kim, Myeong-Ho
Choi, Duck-Kyun
Negative threshold voltage shift in an a-IGZO thin film transistor under X-ray irradiation
title Negative threshold voltage shift in an a-IGZO thin film transistor under X-ray irradiation
title_full Negative threshold voltage shift in an a-IGZO thin film transistor under X-ray irradiation
title_fullStr Negative threshold voltage shift in an a-IGZO thin film transistor under X-ray irradiation
title_full_unstemmed Negative threshold voltage shift in an a-IGZO thin film transistor under X-ray irradiation
title_short Negative threshold voltage shift in an a-IGZO thin film transistor under X-ray irradiation
title_sort negative threshold voltage shift in an a-igzo thin film transistor under x-ray irradiation
topic Chemistry
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9065737/
https://www.ncbi.nlm.nih.gov/pubmed/35515555
http://dx.doi.org/10.1039/c9ra03053k
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