Effect of Annealing Temperature on $\hbox{TiO}_{2}$ -Based Thin-Film-Transistor Performance

TiO
_x
thin-film transistors (TFTs) are fabricated using SiO
₂
as gate dielectrics. The enhancement of the electric characteristics is observed after a postannealing processing including the reduction of the threshold voltage
V
_th
, the increase in mobility μ, and the on/off ratio. The effect of the postannealing temperature on both the TiO
_x
/SiO
₂
interfacial bonding structure and the TiO
_x
crystallinity is investigated. We suggest that the interfacial modification at the TiO
_x
/SiO
₂
interface contributes to the significant reduction of
V
_th
due to the breaking of Si-O-Ti bonding. The improvement of the TiO
_x
crystallinity and interfacial structure leads to the increase in μ and in the on/off ratio. The low-temperature annealing treatment at 200
^°
C is very effective to improve the TiO
_x
/SiO
₂
interface structure.