Homo-Junction Bottom-Gate Amorphous In–Ga–Zn–O TFTs With Metal-Induced Source/Drain Regions

A fabrication process for homo-junction bottom-gate (HJBG) amorphous In–Ga–Zn–O (a-IGZO) thin-film transistors (TFTs) is proposed, in which the a-IGZO section as source/drain (S/D) regions is induced into a low resistance state by coating a thin metal Al film and then performing a thermal annealing in oxygen, with the channel region protected from back etching by depositing and patterning a protective layer. The experimental results show that with a 5 nm Al film and annealing at 200 °C, the sheet resistance of the S/D a-IGZO is reduced to 803 $\Omega $ /□, and keeps stable during a subsequent thermal treatment. In addition, the thin Al ₂ O ₃ film generated by the annealing contributes to an improved thermal stability and ambient atmosphere immunity for the fabricated HJBG TFTs.