Scaling of Coplanar Homojunction Amorphous In–Ga–Zn–O Thin-Film Transistors

Channel length ( L ) and width ( W ) scaling of amorphous In–Ga–Zn–O (a-IGZO) thin-film transistors (TFTs) have been investigated by coplanar homojunction a-IGZO TFTs. The fabricated TFTs have a mobility around 12 cm 2 V -1 s -1 , sub-threshold slope ( S ) of ∼110 mV/decade, threshold voltage around 0.3 V and off-current below 10 -13 A. The TFTs with L > 5 µm have the reduced transconducance ( g m ) at lower V GS , however, the short L < 5 µm TFTs have the g m reduction at higher V GS . Even though the TFTs with smaller channel length ( L ≤5 µm) show proper switching characteristics, threshold voltage lowering and sub-threshold slope degradation are clearly observed.