Rapid Improvement in Thin Film Transistors With Atomic-Layer-Deposited InOx Channels via O2 Plasma Treatment

To improve the electrical performance of thin-film transistors with an atomic-layer-deposited Al
₂
O
₃
dielectric/InO
_x
channel, O
₂
plasma surface treatments of the InO
_x
back channel are explored in comparison with thermal annealing. It is demonstrated that the O
₂
plasma treatment can enhance the device performance much more efficiently than thermal annealing, exhibiting an extremely low-thermal budget. Furthermore, it is revealed that the plasma treatment at a higher temperature can improve the device performance much faster than that at a lower temperature. For a 4 min O
₂
plasma treatment at 200 °C, superior electrical characteristics are achieved, such as a field-effect mobility of 11 cm
²
V
^-1
s
^-1
, a threshold voltage of 0.9 V, a subthreshold swing of 0.38 V/dec, and good gate bias stress stabilities. This is ascribed to faster passivation of oxygen vacancies, removal of more C residues, and weaker surface damage and smaller surface roughness of the InO
_x
back channel in comparison with long plasma treatments at lower temperatures.