Characteristics of Double-Gate Ga–In–Zn–O Thin-Film Transistor

A Ga-In-Zn-O thin-film transistor with double-gate structure is reported. Enhancement-mode operation that is essential to the constitution of a low-power digital circuitry is easily achieved when the upper and lower gate electrodes are tied together. The saturation mobility and the subthreshold swing are improved from 3.65 cm
²
/(V·s) and 0.44 V/dec to 18.9 cm
²
/(V·s) and 0.14 V/dec, respectively, compared with the single-gate structure. We can modulate the threshold voltage of either gate by adjusting the bias on the other gate.