BEOL-Compatible High-Performance a-IGZO Transistors with Record high I_ds,max = 1207 μA/μm and on-off ratio exceeding 10¹¹ at Vds = 1V

In this work, BEOL-compatible high-performance amorphous IGZO-TFTs have been demonstrated using an optimized ITO interlayer for the source/drain contact. The ITO interlayer successfully reduces the Schottky barrier height from 145 meV for Ni/IGZO to 48 meV. The lowest contact resistance of $278 \Omega \cdot \mu \mathrm{m}$ has been demonstrated among IGZO transistors, much lower than the $1.85 \mathrm{k}\Omega \cdot \mu \mathrm{m}$ of direct Ni contact. The contact resistance remains at a very low level of around $278 \Omega \cdot \mu \mathrm{m}$ at 4.3 K. The 60 nm channel length device exhibits a record-high g m peak of $637 \mu \mathrm{S}/ \mu \mathrm{m}$ at $\mathrm{V}_{ds} \quad =1.2\mathrm{V}$ and record-high on-state current of $1207 \mu \mathrm{A}/ \mu \mathrm{m}$ at $\mathrm{V}_{ds} =1\mathrm{V}$, the highest among all IGZO-based transistors.