title: Oxygen Defect-Induced Metastability in Oxide Semiconductors Probed by Gate Pulse Spectroscopy.
abstract: We investigate instability mechanisms in amorphous In-Ga-Zn-O transistors based on bias and illumination stress-recovery experiments coupled with analysis using stretched exponentials and inverse Laplace transform to retrieve the distribution of activation energies associated with metastable oxygen defects. Results show that the recovery process after illumination stress is persistently slow by virtue of defect states with a broad range, 0.85 eV to 1.38 eV, suggesting the presence of ionized oxygen vacancies and interstitials. We also rule out charge trapping/detrapping events since this requires a much smaller activation energy ~0.53 eV, and which tends to be much quicker. These arguments are supported by measurements using a novel gate-pulse spectroscopy probing technique that reveals the post-stress ionized oxygen defect profile, including anti-bonding states within the conduction band.
authors.affiliation: Electrical Engineering Division, Department of Engineering, University of Cambridge, Cambridge CB2 1PZ, United Kingdom.
authors.forename: Sungsik
authors.initials: S
authors.lastname: Lee
authors.affiliation: Electrical Engineering Division, Department of Engineering, University of Cambridge, Cambridge CB2 1PZ, United Kingdom.
authors.forename: Arokia
authors.initials: A
authors.lastname: Nathan
authors.affiliation: Department of Applied Physics, Korea University, 2511 Sejong-ro, Sejong-si, 339-700, Republic of Korea.
authors.forename: Sanghun
authors.initials: S
authors.lastname: Jeon
authors.affiliation: Electrical Engineering Division, Department of Engineering, University of Cambridge, Cambridge CB2 1PZ, United Kingdom.
authors.forename: John
authors.initials: J
authors.lastname: Robertson