Source/Drain Formation of Self-Aligned Top-Gate Amorphous GaInZnO Thin-Film Transistors by $\hbox{NH}_{3}$ Plasma Treatment

The source/drain region of amorphous GaInZnO thin-film transistor with self-aligned top-gate structure was defined by simple $\hbox{NH}_{3}$ plasma treatment instead of complicated processes, such as ion implantation and activation. When the source/drain region of active layer was exposed to $\hbox{NH}_{3}$ gas plasma, the series resistance of the transistor decreased considerably. It exhibited electrical properties, such as a field-effect mobility of 6 $\hbox{cm}^{2}/\hbox{V} \cdot \hbox{s}$, a threshold voltage of 0.21 V, and a subthreshold swing of 0.23 V/dec.