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The effect of oxygen remote plasma treatment on ZnO TFTs fabricated by atomic layer deposition
Author(s) -
Lee Seungjun,
Bang Seokhwan,
Park Joohyun,
Park Soyeon,
Jeong Wooho,
Jeon Hyeongtag
Publication year - 2010
Publication title -
physica status solidi (a)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.532
H-Index - 104
eISSN - 1862-6319
pISSN - 1862-6300
DOI - 10.1002/pssa.200925514
Subject(s) - x ray photoelectron spectroscopy , atomic layer deposition , materials science , analytical chemistry (journal) , thin film transistor , thin film , oxygen , remote plasma , plasma , electrical resistivity and conductivity , threshold voltage , layer (electronics) , chemical vapor deposition , chemistry , nanotechnology , transistor , chemical engineering , electrical engineering , voltage , environmental chemistry , physics , organic chemistry , quantum mechanics , engineering
We deposited ZnO thin films by atomic layer deposition (ALD) and then investigated the chemical and electrical characteristics after plasma treatment. The chemical bonding states were examined by X‐ray photoelectron spectroscopy (XPS). The XPS spectra of O 1s showed that the intensity of oxygen deficient regions of the ZnO film decreased from 27.6 to 19.4%, while the intensity of the oxygen bound on the surface of the ZnO film increased from 15.0 to 21.9% as plasma exposure times increased. The ZnO film exhibited a decrease in carrier concentration from 4.9 × 10 15 to 1.2 × 10 14 cm −3 and an increase in resistivity from 1.2 × 10 2 to 9.8 × 10 3 Ω cm as the plasma exposure times increased. To verify the changes in the chemical and electrical properties of the ZnO films caused by the oxygen remote plasma treatment, ZnO thin film transistors were fabricated and their electrical properties were investigated. We found that the I on/Ioff ratio increased from 7.3 × 10 4 to 8.6 × 10 6 , the subthreshold swings improved from 1.67 to 0.45 V/decade, and the saturation mobility ( µ sat ) decreased from 1.63 to 0.72 cm 2 /V s as plasma exposure times were increased.