Fully Self-Aligned Homojunction Bottom-Gate Amorphous InGaZnO TFTs with Al Reacted Source/Drain Regions

Fully self-aligned homojunction bottom-gate (HJBG) amorphous InGaZnO (a-IGZO) thin-film transistors (TFTs) are realized in this work. A backside-exposure process is employed to fulfill the self-alignment of the gate and SiO2 channel protection layer (PL) using the metal gate as a mask, and the conductive source/drain regions self-aligned with the PL are formed by metal Al reaction treatment. The fabricated TFTs exhibit good device performance. The influence of backside exposure time is studied, and an increase in parasitic resistance is observed when the exposure time is shorter than 16 s which is inferred to be caused by the increased spreading resistance at the edge of the source/drain regions.