Abstract

We investigated effects of base pressure $(P_{\rm base})$ of the deposition chamber on electrical properties and defect states of amorphous In-Ga-Zn-O (a-IGZO) thin films deposited by pulsed laser deposition. The impurity hydrogen concentration was increased by an order of magnitude when $P_{\rm base}$ was deteriorated from $<{{10}}^{-5}$ to ${{10}}^{-3}\ {{Pa}}$ . The optimum oxygen partial pressures $(P_{\rm O2})$ were 2–4 Pa for an optimized deposition condition with the good $P_{\rm base}$ ; on the other hand, off-optimized and/or poor $P_{\rm base}$ require much higher $P_{\rm O2}$ . This result provides an experimental evidence for a charge compensation model by excess oxygen for H-containing a-IGZO. Thermal desorption spectra indicated that the impurity hydrogens originate mainly from water molecules in the residual gas and exist as -OH chemical bonding states in the a-IGZO films. Hard X-ray photoemission spectroscopy revealed that these -OH states form deep defects above the valence band maximum.

© 2014 IEEE

PDF Article

References

You do not have subscription access to this journal. Citation lists with outbound citation links are available to subscribers only. You may subscribe either as an OSA member, or as an authorized user of your institution.

Contact your librarian or system administrator
or
Login to access OSA Member Subscription

Cited By

You do not have subscription access to this journal. Cited by links are available to subscribers only. You may subscribe either as an OSA member, or as an authorized user of your institution.

Contact your librarian or system administrator
or
Login to access OSA Member Subscription