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Effect of High Oxygen Partial Pressure on Carrier Transport Mechanism in a-InGaZnO TFTs

Tijdschriftbijdrage - Tijdschriftartikel

© 1963-2012 IEEE. In this paper, the influence of oxygen partial pressure (PO2) during physical vapor deposition on the field-effect mobility of amorphous InGaZnO (IGZO) thin-film transistor (TFT) is investigated in a wide range of PO2. The field-effect mobility reduced from 12 to 0.1 cm2V s when the PO2 is increased from 0.3 to 1.5 mTorr. Temperature-dependent TFT measurements suggest that carrier transport in the TFTs deposited at the PO2 of 0.3 mTorr can be described according to the multiple trap and release/percolation model. However, the carrier transport in the TFTs deposited at the PO2 of 1.5 mTorr conforms to Mott's variable-range hopping model. The elastic recoil detection analysis indicates that hydrogen concentration in the IGZO film increased with PO2. The X-ray photoelectron spectroscopy results indicate that In vacancy (VIn) defects formed in the IGZO film deposited at high PO2. Scattering induced by hydrogen and pinning of Fermi level below the conduction band edge by VIn are plausible reasons for the low field-effect mobility in TFTs deposited at high PO2.
Tijdschrift: IEEE Transactions on Electron Devices
ISSN: 0018-9383
Issue: 7
Volume: 65
Pagina's: 2833 - 2837
Aantal pagina's: 5
Jaar van publicatie:2018
Trefwoorden:Elektronica en elektrotechniek, Toegepaste natuurkunde