Generation of InGaZnO Nanoparticle by Ar/O₂ Plasma Exposure for Performance Improvement of Oxide TFTs

We studied the improvement in the performance of back-channel-etched oxide TFT with a top gate (TG) by Ar/O <tex-math notation="LaTeX">₂</tex-math> plasma treatment. The generation of oxide nanoparticles in the offset region of amorphous InGaZnO was observed from TEM image upon Ar/O <tex-math notation="LaTeX">₂</tex-math> plasma treatment. This results in the reduction of resistivity in the offset region and performance improvement of dual-gate oxide TFTs. The field-effect mobility increases from 7.7 to 22.5 cm <tex-math notation="LaTeX">²</tex-math> /V <tex-math notation="LaTeX">·</tex-math> s, and the <tex-math notation="LaTeX">VTH</tex-math> shift by positive bias temperature stress (PBTS) decreases from 0.7 to 0.3 V. Performance improvement was observed only in structure, where the TG is exposed in air. The performance improvement of the TFTs results in the operation frequency of the ring oscillator (RO) made of the dual-gate TFTs increasing from 17.75 to 113.4 kHz.