Abstract

We performed constant positive gate bias stress tests on sputter-deposited amorphous In–Ga–Zn–O (a-IGZO) thin-film transistors (TFTs) fabricated with various annealing conditions. We found that the time evolution of threshold voltage shift ( $\Delta V _{\rm th}$ ) during the stress test exhibits two different behaviors; a power function type and a logarithmic function type. Combining with thermal desorption spectroscopy (TDS), we found that the $\Delta V _{\rm th}$ type changes from the log-function type to the power-function type as ${{H}} _{2}$ desorption increases. The power-function type is attributed to a H-diffusion limited process. As for the log-function type, the magnitude of $\Delta V _{\rm th}$ has correlation with the hysteresis width in a first transfer curve and the desorption amount of ${{H}} _{2} {{O}}$ and ${{O}} _{2}$ species between 200 $^{\circ}{{C}}$ –300 $^{\circ}{{C}}$ . Hence, it is considered that the traps causing the log-function type $\Delta {\rm V} _{\rm th}$ are meta-stable states related to O- and/or OH-related weak bonds.

© 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