Thermally stable n+-InGaZnO layer stacked by fluorinated silicon nitride for self-aligned thin-film transistor application

Thermal stability of amorphous InGaZnO (a-IGZO) film stacked by fluorinated silicon nitride (SiN_x:F) was investigated. The electrical properties of stacked a-IGZO, including the resistivity of ~4.0 × 10^-3 Ω-cm, the carrier concentration of ~10²⁰ cm^-3, and Hall mobility of ~19.0 cm²/Vs, showed highly thermally stable irrespective of annealing temperature. On the basis of this phenomenon, a novel bottom-gate and self-aligned IGZO TFT combined the back-side exposure technique with directly stacked IGZO/SiN_x:F layers in the S/D regions was fabricated. The proposed a-IGZO TFT exhibits good electrical characteristics and highly thermal stability even annealing as high as 350 °C.