The performance improvement of N₂ plasma treatment on ZrO₂ gate dielectric thin-film transistors with atmospheric pressure plasma-enhanced chemical vapor deposition IGZO channel

The aim of this paper is to illustrate the N₂ plasma treatment for high-κ ZrO₂ gate dielectric stack (30 nm) with indium-gallium-zinc-oxide (IGZO) thin-film transistors (TFTs). Experimental results reveal that a suitable incorporation of nitrogen atoms could enhance the device performance by eliminating the oxygen vacancies and provide an amorphous surface with better surface roughness. With N₂ plasma treated ZrO₂ gate, IGZO channel is fabricated by atmospheric pressure plasma-enhanced chemical vapor deposition (AP-PECVD) technique. The best performance of the AP-PECVD IGZO TFTs are obtained with 20 W-90 sec N₂ plasma treatment with field-effect mobility (μ_FET) of 22.5 cm²/V-s, subthreshold swing (SS) of 155 mV/dec, and on/off current ratio (I_on/I_off) of 1.49 × 10⁷.